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Hindawi Publishing CorporationInternational Journal of BiodiversityVolume 2013 Article ID 642579 13 pageshttpdxdoiorg1011552013642579
Research ArticleDiversity Distribution and Abundance ofPlants in Lewoh-Lebang in the Lebialem Highlands ofSouthwestern Cameroon
B A Fonge1 D J Tchetcha1 and L Nkembi2
1 Department of Botany and Plant Physiology University of Buea PO Box 63 Buea Cameroon2 Environment and Rural Development Foundation (ERuDeF) PO Box 189 Buea Cameroon
Correspondence should be addressed to B A Fonge ambofongeyahoocom
Received 24 April 2013 Accepted 26 June 2013
Academic Editor Rafael Riosmena-Rodrıguez
Copyright copy 2013 B A Fonge et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
A survey was conducted between October 2010 and June 2011 to determine the diversity distribution and abundance of plants in4 sites of the Lebialem highlands and to relate species diversity and abundance to altitude and soil types Twelve (12) plots eachof 1 ha (250times 40m) were surveyed at the submontane and montane altitudes of the sites One hundred (100) species belongingto 82 genera were identified with the genera Cola and Psychotria being the most represented Vulnerable species included Guareathompsonii Schefflera hierniana Allanblackia gabonensis Cyclomorpha solmsii Vepris trifoliolata and Xylopia africana Speciessuch as Xymalos monospora Tricalysia atherura and Piptostigma oyemense present in the study area were endemic to CameroonDiversity and distribution of plants were affected by parameters such as the altitude and the soil type Soil analysis revealed thatdiversity in the study area was affected by the organic carbon nitrogen calcium and the cation exchange capacity of the soil
1 Introduction
Biodiversity is the degree of variation of life forms within agiven ecosystem biome or entire planet [1] It encompassesall species of plants animals andmicroorganisms the ecosys-tem and ecological processes of which they are parts It isan umbrella term for the degree of naturersquos variety includingboth number and frequency of ecosystems species or genesin a given assemblage Wilson [2] defines biodiversity as thevariety of organisms considered at all levels from genetic vari-ants belonging to the same species through arrays of speciesto arrays of genera families and still higher taxonomic levels
Besides South Africa Cameroon is the most biologicallyrich country known to date on the African continent [3]It encompasses an intricate mosaic of diverse habitats withmoist tropical forest dominating the south and south-east andcovering 54 of the country mountain forest and savannahin the highlands and sub-Sahelian savannah and near desertin the far north [3]These diverse habitats harbourmore than9000 species of plants 160 species of which are endemicThe majority of the endemic taxa are concentrated around
Mount Cameroon and other highland areas During thelast few decades deforestation of tropical forests areas hasaccelerated at an alarming rate as extensive areas of forest arebeing cleared every year [4] Man affects the forest ecosystemwith activities such as agroindustries shifting cultivationand hunting There has been an overwhelming concernabout the loss of tropical diversity and an emphasis onthe identification of biodiversity hot spots in an attempt tooptimize conservation strategies [5]
Diversity studies carried out in Cameroon have coveredmany parts of the country but left out certain regions despitetheir richness in plant diversity [6 7] An example of sucha region is the Lewoh-Lebang area in the Lebialem DivisionLebialem is located in the southwest region of Cameroon andit is characterized by a hilly topography with a rich diversityof flora and fauna This mountain ecosystem has been underserious pressure from the local people The ecosystem is acentre of high endemism for many taxa (plants amphibiansmammals and birds) and its destruction could lead to thelocal extinction of globally threatened biodiversity (plantsmammals etc) watershed destruction and degradation of
2 International Journal of Biodiversity
livelihood systems property and lives The region also holdssome of the globally threatened and endemic species suchas the critically endangered cross river gorilla chimpanzeeflying squirrel endangered Bannermanrsquos Turaco and BandedWattle-eye vulnerable Red-headed Picathartes [8]The studyarea is part of the Bamboutos Mountain Range which isa stronghold of montane biodiversity These ecosystemsaround the Bamboutos Mountain continue to provide valu-able goods and services to local people in the region andare an important watershed lodging the tributaries of ManyuRiver that drain into the cross river Due to precedentgeological and geographical history of these mountain areasand coupled with the high annual rainfall (2000 to 3000mm)and humidity these areas are perpetually having landslides[9 10] Most of the landslides are as a result of anthropogenicactivities of the communities around the mountain [10] TheNweh people (tribe in the study site) practice slash and burnagriculture with a bimodal annual farming cycle which isentirely dependent on the rain fall patterns that results infrequent landslides [9] Information on the type and thedistributional patterns of plants may help to put in placeproper management schemes on biodiversity conservationThis work therefore assesses the diversity distribution andabundance of plants found in Lewoh-Lebang landscape inCameroon so as to propose management schemes for biodi-versity conservation
2 Materials and Methods
21 Study Area Lebialem is located in the northeastern partof the southwest region of Cameroon (latitudes 5∘381015840N and5∘431015840N and between longitudes 9∘581015840E and 10∘271015840E) [11 12]Lewoh-Lebang is located between latitudes 5∘451015840 and 5∘471015840Nand longitudes 9∘911015840E and 9∘941015840E and at altitudes rangingfrom 1456 to 1835m (Figure 1) The climate of this regionis similar to that of the Cameroon mountain range whichis characterized by high winds and low sunshine [8] Theaverage daily temperature varies very much with seasons buthas ranges of 17 to 32∘C and the mean annual rainfall rangefrom 2000 was 3000mm [8] The main vegetation type isgrassland with patches of montane and submontane forestsmainly as a result of human activities particularly cocoyamfarming in the lowland forest [13]
22 Sampling Sampling was carried out in four differentsites Atullah (5∘461015840N and 9∘931015840E) Leleng (5∘471015840N and9∘941015840E) Mbindia (5∘451015840N and 9∘911015840E) and Nyitebong(5∘461015840N and 9∘911015840E) Each site was divided into submontane(800ndash1600m altitude) andmontane levels (ge1600m altitude)The study sites and the altitudes used were subdividedfollowing the classification done by Harvey et al [14] Withineach of the stratum a plot of 1 ha (40m times 250m) was laidand was subdivided into 10 subplots of 10 times 10m placed atregular intervals of 50m from each other Within each plotall individual trees were identified measured and recordedTaxa were identified in situ by a taxonomist from the LimbeBotanic GardenThe diameters at breast height of the specieswere measured using a diameter tape Trees were grouped
into the following diameter classes small trees (1ndash99 cm)medium-sized trees (10ndash299 cm) and large trees (gt299 cm)following a grouping done by Kenfack et al [15] Thesespecies were further grouped into four life forms defined bytheir maximum attainable heights as follows treelets (smalltrees) (lt10m) understorey (10ndash20m) canopy (20ndash30m)and emergent (gt30m) [16]
Voucher specimens were prepared and compared withthose at the Limbe Botanic Garden Herbarium (SCA) andthe Cameroon National Herbarium (YA) Rare species wereidentified in situ to prevent forward destruction At each alti-tude level soil samples were collected air dried and standardprocedures [17ndash20] were used to analyse the samples Thefollowing soil parameters were analysed soil pH determinedin the ration of 2 5 (wv) soil water suspension organiccarbon by chromic acid digestion and spectrophotometricanalysis [18] Total nitrogen was determined by wet aciddigestion [17] and exchangeable cations (calcium magne-sium and potassium) were extracted using the Mehlich-3procedure [19] and atomic absorption spectrophotometryAvailable phosphorus was extracted by the Bray-1 procedureand analysed using the molybdate blue procedure describedby Murphy and Riley [20]
23 Data Processing and Analysis Species diversities weredetermined using the Shannon-Weaver Diversity Index (119867) 119867 = (119875119894) (logn 119875119894) where 119875119894 = 119899119894119873 119899119894 = number ofindividuals of species 119894 and119873 = total number of individuals[21] Pearson correlation was conducted to determine therelationship between the soil physicochemical factors andspecies richness and diversity
3 Results
Table 1 shows the different plant species their code authorsand life forms found in the study sites (Atullah LelengMbindia and Nyitebong) A total of 100 species were record-ed in all the four sites belonging to 39 families and 82genera in which 94 were identified to species level and 6identified to genus level Out of the 100 species identified inthe study sites 39 species were treelets mostly lt10m talland 24 species were understory trees lt20m tall and seldomreaching the canopy Twenty-five (25) species were maincanopy species and 11 species were emergent trees species
From the 39 families recorded in the study sites theRubiaceae had the highest number of genera (12) and species(17) followed by the Sterculiaceae with 6 species and 3 generaA total of 82 genera were recorded in the study sites Cola(Rubiaceae) were the most abundant genera with the highestnumber of species (4) This was followed by the generaStrombosia (Olacaceae) and Vernonia (Asteraceae) having 3species each (Table 1)
Table 2 shows the different trees species found in thedifferent study sites and their relative abundance In the foursites 2113 individuals were sampled The species with thehighest number of individual wasMacarangamonandra (179)with a relative abundance of 847 It was followed by Pen-tadesma butyracea (131 individuals and relative abundance
International Journal of Biodiversity 3
0 100(km)
N
N
National boundariesRegional boundariesSouthwest region
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
livelihood systems property and lives The region also holdssome of the globally threatened and endemic species suchas the critically endangered cross river gorilla chimpanzeeflying squirrel endangered Bannermanrsquos Turaco and BandedWattle-eye vulnerable Red-headed Picathartes [8]The studyarea is part of the Bamboutos Mountain Range which isa stronghold of montane biodiversity These ecosystemsaround the Bamboutos Mountain continue to provide valu-able goods and services to local people in the region andare an important watershed lodging the tributaries of ManyuRiver that drain into the cross river Due to precedentgeological and geographical history of these mountain areasand coupled with the high annual rainfall (2000 to 3000mm)and humidity these areas are perpetually having landslides[9 10] Most of the landslides are as a result of anthropogenicactivities of the communities around the mountain [10] TheNweh people (tribe in the study site) practice slash and burnagriculture with a bimodal annual farming cycle which isentirely dependent on the rain fall patterns that results infrequent landslides [9] Information on the type and thedistributional patterns of plants may help to put in placeproper management schemes on biodiversity conservationThis work therefore assesses the diversity distribution andabundance of plants found in Lewoh-Lebang landscape inCameroon so as to propose management schemes for biodi-versity conservation
2 Materials and Methods
21 Study Area Lebialem is located in the northeastern partof the southwest region of Cameroon (latitudes 5∘381015840N and5∘431015840N and between longitudes 9∘581015840E and 10∘271015840E) [11 12]Lewoh-Lebang is located between latitudes 5∘451015840 and 5∘471015840Nand longitudes 9∘911015840E and 9∘941015840E and at altitudes rangingfrom 1456 to 1835m (Figure 1) The climate of this regionis similar to that of the Cameroon mountain range whichis characterized by high winds and low sunshine [8] Theaverage daily temperature varies very much with seasons buthas ranges of 17 to 32∘C and the mean annual rainfall rangefrom 2000 was 3000mm [8] The main vegetation type isgrassland with patches of montane and submontane forestsmainly as a result of human activities particularly cocoyamfarming in the lowland forest [13]
22 Sampling Sampling was carried out in four differentsites Atullah (5∘461015840N and 9∘931015840E) Leleng (5∘471015840N and9∘941015840E) Mbindia (5∘451015840N and 9∘911015840E) and Nyitebong(5∘461015840N and 9∘911015840E) Each site was divided into submontane(800ndash1600m altitude) andmontane levels (ge1600m altitude)The study sites and the altitudes used were subdividedfollowing the classification done by Harvey et al [14] Withineach of the stratum a plot of 1 ha (40m times 250m) was laidand was subdivided into 10 subplots of 10 times 10m placed atregular intervals of 50m from each other Within each plotall individual trees were identified measured and recordedTaxa were identified in situ by a taxonomist from the LimbeBotanic GardenThe diameters at breast height of the specieswere measured using a diameter tape Trees were grouped
into the following diameter classes small trees (1ndash99 cm)medium-sized trees (10ndash299 cm) and large trees (gt299 cm)following a grouping done by Kenfack et al [15] Thesespecies were further grouped into four life forms defined bytheir maximum attainable heights as follows treelets (smalltrees) (lt10m) understorey (10ndash20m) canopy (20ndash30m)and emergent (gt30m) [16]
Voucher specimens were prepared and compared withthose at the Limbe Botanic Garden Herbarium (SCA) andthe Cameroon National Herbarium (YA) Rare species wereidentified in situ to prevent forward destruction At each alti-tude level soil samples were collected air dried and standardprocedures [17ndash20] were used to analyse the samples Thefollowing soil parameters were analysed soil pH determinedin the ration of 2 5 (wv) soil water suspension organiccarbon by chromic acid digestion and spectrophotometricanalysis [18] Total nitrogen was determined by wet aciddigestion [17] and exchangeable cations (calcium magne-sium and potassium) were extracted using the Mehlich-3procedure [19] and atomic absorption spectrophotometryAvailable phosphorus was extracted by the Bray-1 procedureand analysed using the molybdate blue procedure describedby Murphy and Riley [20]
23 Data Processing and Analysis Species diversities weredetermined using the Shannon-Weaver Diversity Index (119867) 119867 = (119875119894) (logn 119875119894) where 119875119894 = 119899119894119873 119899119894 = number ofindividuals of species 119894 and119873 = total number of individuals[21] Pearson correlation was conducted to determine therelationship between the soil physicochemical factors andspecies richness and diversity
3 Results
Table 1 shows the different plant species their code authorsand life forms found in the study sites (Atullah LelengMbindia and Nyitebong) A total of 100 species were record-ed in all the four sites belonging to 39 families and 82genera in which 94 were identified to species level and 6identified to genus level Out of the 100 species identified inthe study sites 39 species were treelets mostly lt10m talland 24 species were understory trees lt20m tall and seldomreaching the canopy Twenty-five (25) species were maincanopy species and 11 species were emergent trees species
From the 39 families recorded in the study sites theRubiaceae had the highest number of genera (12) and species(17) followed by the Sterculiaceae with 6 species and 3 generaA total of 82 genera were recorded in the study sites Cola(Rubiaceae) were the most abundant genera with the highestnumber of species (4) This was followed by the generaStrombosia (Olacaceae) and Vernonia (Asteraceae) having 3species each (Table 1)
Table 2 shows the different trees species found in thedifferent study sites and their relative abundance In the foursites 2113 individuals were sampled The species with thehighest number of individual wasMacarangamonandra (179)with a relative abundance of 847 It was followed by Pen-tadesma butyracea (131 individuals and relative abundance
International Journal of Biodiversity 3
0 100(km)
N
N
National boundariesRegional boundariesSouthwest region
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
of 620) Gaertnera paniculata and Maesa lanceolata (109individuals and relative abundance of 516 each)
Thirteen (13) species were common in all the foursites Trilepisium madagascariense (Moraceae) Ficus mucuso(Moraceae) Gaertnera paniculata (Rubiaceae) Macarangamonandra (Euphorbiaceae) Psychotria strictistipula (Rubi-aceae) Maesa lanceolata (Myrsinaceae) Tabernaemontanacrassa (Apocynaceae) Manilkara sp (Sapotaceae) Vernoniaconferta (Asteraceae) Warneckea jasminoides (Melastomat-aceae) Carapa grandiflora (Meliaceae) Hannoa klaineana(Simaroubaceae) and Zanthoxylum gilletii (Rutaceae)
In Nyitebong 60 species were recorded from 26 familiesand 51 genera The most abundant species were Pentadesmabutyracea (123 individuals) and Gaertnera paniculata (103)with several families having only one species represen-tative Allanblackia gabonensis (Clusiaceae) Beilschmiediasp1 (Lauraceae) Cola megalophylla (Sterculiaceae) Diogoazenkeri (Olacaceae) Piptostigma oyemense (Annonaceae)Pycnanthus angolensis (Myristicaceae) Spathodea campanu-lata (Bignoniaceae) andKigelia africana (Bignoniaceae) wererare species having only one individual recorded in the area
In Mbindia 59 species were recorded from 28 fami-lies and 51 genera The most abundant species were Colaheterophylla (46 individuals) and Dracaena arborea (32individuals) The rare species having only one individ-ual included Craterispermum aristatum (Rubiaceae) andMicrodesmis puberula (Pandaceae) which was found only inMbindia
In Atullah 46 species were recorded from 24 families and51 genera The most abundant species wereMaesa lanceolata(58 individuals) and Xymalos monospora (54 individuals)while Balanophora coriacea (Rubiaceae) was the only rarespecies
In Leleng 49 species were recorded from 28 familiesand 42 genera The most abundant species were Macarangamonandra (106 individuals) and Vernonia conferta (31 indi-viduals) The rare species having only one individual andoccurring only at Leleng included Euphorbia desmindi(Euphorbiaceae) and Piper capense (Piperaceae)
31 Diversity The Shannon-Weaver Diversity Index (1198671015840)Pieloursquos Evenness and the species richness (119889) of the differentstudy sites are shown in Table 3 Nyitebong and Mbindiasubmontane forests were the most diverse communities with
Figure 2 Similarities between the different study sites
the highest indices of 318 and 310 respectively The leastdiverse sites was Leleng submontane with 1198671015840 = 25261 Interms of evenness the submontane forest at Mbindia had themost evenly distributed species with Pieloursquos Evenness valueof 089 The richest forest in terms of number of species wasthe submontane forest at Nyitebong with Margalef richnessvalue of 712
32 Species Similarity Figure 2 represents a dendrogramshowing similarities between the four different study sitesThe distance correlation (ward linkage) between Attuleh andLeleng is minimal (044) and this shows that Attuleh andLeleng have many plants species that are similar and theirsimilarity index was 778 Nyitebong was less similar to allthe other sites
Figure 3 shows the different diameter classes found inthe different study sites The diameter range was grouped assmall trees (1ndash99 cm)medium-sized trees (99ndash299 cm) andlarge trees (gt299 cm)The four sites were dominated by treesspecies having diameters ranging from 10 to 99mm (smalltrees) Medium-sized trees were also present in all the sitesThere were very few trees with large diameters (gt299 cm)occurring at Nyitebong (07) Mbindia (41) and Leleng(30) and no large tree was found in Attuleh forest
In Nyitebong 464 trees (821) with DBH range of 10ndash99mm and 101 trees (179) with DBH range of 100ndash299mmwere recorded In Leleng 263 trees (727) with DBH rangeof 1ndash99 cm 88 trees (243) with DBH range of 10ndash299 cmand 11 trees (30) with DBH ge 30 cm were recorded InNyitebong 596 trees (821) with DBH range of 1ndash99 cm125 trees (172) with DBH range of 10ndash299 cm and 5 trees(07) with DBH ge 30 cm were recorded In Mbindia 379trees (817) with DBH range 1ndash99 cm 66 trees (142) withDBH range of 10ndash299 cm and 19 trees (41) with DBH ge30 cm were recorded
Figure 4 shows the similarities in diameter at breastheight between different study sites It shows that the DBHof plants in Attuleh and Nyitebong is very similar and thatMbindia has plants with DBH different from that of plantsfound in all other sites Trees and shrubs had very similar
International Journal of Biodiversity 9
Table 4 Physicochemical properties of soils at the different sites
Locationparameter Org C pH Total N Bray P cmol(+)kg CN Sand Clay Silt Water ugg or ppm K Ca Mg Na ECEC CEC
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
Attuleh S lowastDBH class Leleng S lowastDBH class
Nyitebong S lowastDBH classMbindia S lowastDBH class
gt299 mm
10ndash99 mm100ndash299 mm
DBH class
gt299 mm
Figure 3 Diameter class distribution of the different study sites
5092
6728
8364
10000
Dendrogram for DBHSingle linkage correlation coefficient distance
LelengAttuleh MbindiaNyitebong
Variables
Sim
ilarit
y
Figure 4 Similarities in diameter at breast height between thedifferent study sites
diameters at Attuleh and Nyitebong (5366) The diameter ofplants atMbindia was different from the diameter of plants inall other areas (5091)
33 Substrate Parameters Table 4 shows the physico-chemi-cal properties of soils at the different forest levels The pHof the study sites was acidic at all the forest levels rangingfrom 492 to 522 with Nyitebong submontane being themost acidic site The calcium (4864 cmolkg) magnesium(2043 cmolkg) and ECEC (7444 cmolkg) content of thesoil was higher in Attuleh than in all other sites The CEC(25540 cmolkg) and Bray P (6750 ppm) of the soil werehigher inNyitebong submontane than in all other sitesNyite-bong montane site had the lowest calcium (014 cmolkg)magnesium (018 cmolkg) and potassium (028 cmolkg)content compared with the other sites The organic carbon(4145) total nitrogen (0601) and CN ratios (9310)of the soil were higher in Nyitebong montane than in allother sites The soils of Nyitebong montane and submontanesites were sandy having the sand content of 5740 and5106 respectively Soils at Attuleh had almost the same soiltexture percentages while in Leleng the montane had highclay content (4040) compared with the submontane with2404 clay and 2674 of silt
Table 5 shows the correlation between soil parametersdiversity indices index of evenness and species richnessThe diversity and evenness of plants in study sites werenegatively correlated with pH while there was no correlationwith species richness (119875 gt 001 and119875 gt 005 resp) Evennesswas positively correlated with calcium and ECEC (119875 gt 005)The diversity of plants was positively correlated with Brayphosphorus content of the soil (119875 gt 005)
4 Discussions
41 Species Diversity in the Study Sites The forests of south-western Cameroon are generally known to be rich in speciesdiversity because they are located within the high rainfallzone of the Guinean equatorial tropical forest Tropical forestcontains more than half of the global species diversity and itis often subjected to increasing anthropogenic pressurewhichleads to loss of biodiversity [22] It is also believed that thisarea formed a Pleistocene refugium during the last glacial
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
period becoming isolated and allowing the development ofregional endemic species [3]
In the study area the most dominant family was theRubiaceae and this implies that the Rubiaceae could be themost dominant tree family in the Guinean equatorial forestThis result was in line with the findings of Ndam et al[23] and Fonge et al [24] who reported that the Rubiaceaewas the most dominant tree family in the Mount Cameroonregion Kenfack et al [15] also report Rubiaceae to be themost dominant tree family in the Korup National Park andKouame et al [25] reported that the Rubiaceae was the mostdominant tree family in the Azagny National Park of CoteDrsquoIvoire The submontane forest had more species than themontane forest and this could be due to the fact that speciesrichness decreaseswith altitude [3] Twenty-eight (28) speciesof plants were found only in the submontane forest while 15plant species were found only in themontane forestThis highnumber of species found in the submontane area could bedue to the disturbance (agriculture) which brings about theestablishment of secondary species [11] Thirteen (13) speciesof plants cut across all the 4 study sites and the ecology ofthese species show that they thrive across a wide range ofhabitats including both montane and submontane habitats
Allanblackia gabonensis is a rare species occurring only atNyitebongThe absence of this species in the other sitesmightbe due to deforestation At these sites (Mbindia Atullah andLeleng) human activities particularly agriculture (slash andburn farming system) were higher than those in NyitebongAllanblackia gabonensis is of particular interest because itis vulnerable and of great economic value This result is inline with the findings of Ndam et al [26] who also reportedAllanblackia gabonensis to be a rare species in the MountCameroon montane forest
42 Species Richness and Diversity According to Kent andCoker [27] a forest community is said to be rich if it hasa Shannon Diversity value ge35 All our sites had Shannon-Weaver Diversity indices values below 35 making the forestrelatively poor in diversity The submontane forest at Nyite-bong was the most diverse and also the most even forest ofall the four study sites followed by the submontane forestat Mbindia This could be due to the fact that forests atNyitebong and Mbindia were relatively undisturbed throughanthropogenic factors such as agriculture and hunting Sec-ondly it might also be due to the abandonment of farmingactivities by the peasants and the successional changes in thevegetation as lands had been left to fallow for a very longtime in both areas [24]This had resulted in the reappearanceof many plant species in this area The submontane forest atLeleng was the least diverse of all the sites This might bedue to anthropogenic effects In the Leleng area cultivationhunting and collection of forest products were the mainactivities of the local population Also we observed largeplantations of cocoyams cultivated around the forest edgesand this crop is the main staples of the local communityaround the forest and is also their source of incoming henceincreasing the pressure on the surrounding forest [12 24]Theaction of the local people has led to untold suffering includinghomelessness loss of human lives properties and forest land
substantial loss of biodiversity habitats and loss of incomesources leading to extreme levels of poverty [9 28] There isalso loss of cultural values and serious degradation of habitats
43 Threatened Species in the Study Sites Themajority of thetaxa found in the studied area are of conservation value andimportanceThey occurmostly in the intricatemosaic of low-land and ridge forest formations and the ecological fragilityand anthropogenic pressure on the montane forest andsubmontane forest suggest that these ecotypes are of consid-erable conservation value Out of the 100 species recorded 6species were threatened These species included Allanblackiagabonensis Vepris trifoliolata Schefflera hierniana Xylopiaafricana Guarea thompsonii and Cyclomorpha solmsii andthese were all vulnerable species according to IUCN [29]The presence of these species in the study sites could bebecause this area is within the Mount Cameroon regionwhich is reported to be a centre of biodiversity and endemismin Cameroon [30] Scholes and Biggs [30] also found thatmontane forest contains several centre of endemism for birdsmammals and plants The floristic composition and thethreatenedendangered species found in the IUCN categoriesshow that this area is qualitatively diverse The occurrenceof threatened species in the area might also be due to theaccidental nature of the terrain which restricted humanactivities especially agriculture to areas that were relativelyaccessible thus allowing the inaccessible areas to be relativelyundisturbed Some of the threatened species such as Guareathompsonii Cyclomorpha solmsii and Schefflera hiernianawere used in the area as timber medicine and fencingrespectively and this could be the reason why these speciesdid not appear in all the study sites The following speciesXymalosmonospora Tricalysia atherura and Piptostigma oye-mensewhich are endemic to Cameroon were also recorded inour study area
44 Substrate Parameters Based on studies of soil propertiesphosphorus present inmost tropical soils is lacking due to soilacidity and fixation therefore becomes unavailable to plantsfor proper growth and development [31]
Forest ecosystems are highly diversified in plant speciesand this great floristic diversity is supported by relativelypoor and acidic soils [1] Nyitebong was the most diverseof all sites having very acidic soils that have low calciummagnesium potassium and sodium concentrations Thisresult corroborates the findings of Fonge et al [24] whoreported similar results in soils of the Mount Cameroonregion Nyitebong submontane forest also had the highestvalues in terms of carbon nitrogen ratio organic carbon totalnitrogen Bray phosphorus and CEC and this explains itshigh floristic diversity The high content of these elementscould be because of the continuous accumulation of organicmaterial on the top soil over the years from pioneer species(bryophytes ferns orchids etc) litter from trees shrubs anddeadmacro- andmicroorganismswhich could be responsiblefor the regeneration of the vegetation cover [24 32] Nyite-bong submontane had the highest percentages of organiccarbon and this might be the reason why they had a greaterdiversity compared with the other sites
12 International Journal of Biodiversity
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
Pearson correlation shows that organic carbon was pos-itively correlated with the total nitrogen and the carbon-nitrogen ratio These two nutrients are essential macronu-trients for plant growth and vegetation establishment Thehumid substances from the decay of organic materials aidin weathering of the parent rock and thereby increasing theamount of silt and clay in the soil Nevertheless this wasnot the case in Nyitebong where the sand content was highand this high content of sand could be attributed to thecomposition of the parent rock material and the weatheringprocesses involved during soil formation and high rainfallwhich causes the leaching of nutrients from the soil Lelengmontane forest unlike most montane ecosystems had soilswith high clay content This might be due to the fact that theslope at Leleng was not steep and thus reducing the rate oferosion Diversity was positively correlated with phosphorusconcentration in the soil while it was negatively correlatedwith the pH Evenness was negatively correlated with pHand positively correlated with ECEC and the calcium contentof the soil Potassium did not correlate with any of theparameters meaning that potassium did not influence thediversity and distribution of species in the study area Phos-phorus concentration of the soils (675 ppm) was the highestin Nyitebong submontane but this value was relatively lowcompared with the findings of Mvondo Ze [33] who reportedthe phosphorus content of Mount Cameroon soils to bebetween 12 and 16 ppmThe low phosphorus concentration ofsoils in the study sitesmight be the reason for the lowdiversityin the area Phosphorus was negatively correlated with pHin our study sites and this was in line with the findings ofWada and Gunjigake [34] who reported that the amount ofphosphorus in soils is correlated with the pH of the soil
5 Conclusion
Biodiversity is in need of wisemanagement not only to satisfyinternational pressures and obligations but also becausebiodiversity could be the basis of most rural sustainablelivelihoods in new economic sectors The montane andsubmontane vegetation was subjected to human disturbanceIn the Lebialem region most of the tree species are treeletswith a height range of about lt10m signifying anthropogenicdisturbance Rubiaceae was the most common family withCola being the most abundant genera followed by Strombosia(Olacaceae) andVernonia (Asteraceae)The tree species weregreatly affected by the soil physicochemical properties andwere positively correlated with Bray phosphorus
6 Recommendations
The population needs to be educated on sustainable farmingtechniques (eg agroforestry that maximizes production inreduced surface area) and sustainable forest managementThis will help reduce the pressure on the forest and thusconserving the natural environment
More research should be geared towards effects of climateand landuse changes factors on vegetation establishment inthis area as this will help in the management of landslideactivities in these ecosystems
Reforestation programmes should be carried out by thegovernment and councils to improve the water catchment
Acknowledgments
Special thanks go to the University of Buea that gave theinitial grant used to carry out this research The authorsgratefully acknowledge the collaboration of the villagers inthe Lewoh and Lebang villages in this study as well as theLimbe Botanic Garden and the botanists of the CameroonNational Herbarium for their help in validating the identitiesof specimens Also the financial support of the NGO ldquoEnvi-ronment and Rural Development Foundationrdquo (ERUDEF) isgratefully acknowledged
References
[1] G Uno R Storey and R Moore Principles of Botany McGraw-Hill 2001
[2] E O WilsonThe Diversity of Life Penguin Books 1992[3] T C H Sunderland J A Comiskey S Besong H Mboh J
Fonwebon and M A Dione ldquoVegetation Assessment of Taka-manda Forest Reserve Cameroonrdquo Smithsonian Institution2003
[4] M G P Tchouto Plant diversity in a central African rainfor-estImplications for biodiversity conservation inCameroon [PhDthesis] University of EdinburghRoyal Botanic Garden of Edin-burgh 2004
[5] H J Beentje Centres of Plant Diversities in Africa the Biodiver-sity of African Plants Kluwer Academic PublishersTheNether-lands 1996
[6] J E AdjanohounNAboubakar KDramane et al ldquoTraditionalMedicine and Pharmacopoeia Contribution to Ethnobotanicaland Floristic studies in Cameroonrdquo OAUSTRC pp 224ndash3151996
[7] MMbolo ldquoLa collecte et lrsquoanalyse des donnees statistique sur lesproduits forestiers non ligneux une etude pilote au CamerounrdquoDepartement des forets In Programme produit forestiers nonligneux FAO Rome Italie 2002
[8] L Nkembi ldquoComparative study of community and governmentpatrols in enhancing sustainable wildlife conservation in theBanyang-Mbo sanctuary Cameroonrdquo Tech Rep Ministry ofEnvironment and Forestry MINEF 2004
[9] S N Ayonghe and E B Ntasin ldquoThe geological control andtriggering mechanism of landslides of the 20th July 2003with the Bamboutos Caldera Cameroonrdquo Journal of CameroonAcademic Science vol 7 no 3 pp 191ndash203 2008
[10] A Zogning C Ngouanet and O Tiafack ldquoThe catastrophicgeomorphological processes in humid tropical Africa a casestudy of the recent landslide disasters in Cameroonrdquo Sedimen-tary Geology vol 199 no 1-2 pp 13ndash27 2007
[11] D A Focho E A P Nkeng B A Fonge et al ldquoDiversity ofplants used to treat respiratory diseases in Tubah northwestregion Cameroonrdquo African Journal of Pharmacy and Pharma-cology vol 3 no 11 pp 573ndash580 2009
[12] D A Focho W T Ndam and B A Fonge ldquoMedicinal plantsof AguambumdashBamumbu in the Lebialem highlands southwestprovince of Cameroonrdquo African Journal of Pharmacy andPharmacology vol 3 no 1 pp 1ndash13 2009
International Journal of Biodiversity 13
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981
[13] B A Fonge E A Egbe A G N Fongod et al ldquoEthnobotanysurvey and uses of plants in the Lewoh-Lebang communitiesin the Lebialem highlands South West Region CameroonrdquoJournal of Medicinal Plants Research vol 6 no 5 pp 855ndash8652012
[14] Y Harvey B Tchieuque andM Cheek ldquoThe plants of Lebialemhighland Cameroonrdquo A conservation checklist Royal botanicGarden Kew UK pp 7ndash31 2010
[15] D Kenfack D WThomas G Chuyong and R Condit ldquoRarityand abundance in a diverse African forestrdquo Biodiversity andConservation vol 16 no 7 pp 2045ndash2074 2007
[16] G B Chuyong D Kenfack K E Harms D W Thomas RCondit and L S Comita ldquoHabitat specificity and diversity oftree species in an African wet tropical forestrdquo Plant Ecology vol212 no 8 pp 1363ndash1374 2011
[17] A Buondonno A A Rashad and E Coppola ldquoComparingtests for soil fertility II The hydrogen peroxidesulfuric acidtreatment as an alternative to the copperselenium catalyzeddigestion process for routine determination of soil nitrogen-Kjeldahlrdquo Communications in Soil Science amp Plant Analysis vol26 no 9-10 pp 1607ndash1619 1995
[18] D L Heanes ldquoDetermination of total organic-C in soils byan improved chromic acid digestion and spectrophotometricprocedurerdquo Communications in Soil Science amp Plant Analysisvol 15 no 10 pp 1191ndash1213 1984
[19] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984
[20] J Murphy and J P Riley ldquoA modified single solution methodfor the determination of phosphate in natural watersrdquoAnalyticaChimica Acta vol 27 pp 31ndash36 1962
[21] A E Magaurran Ecological Diversity and Its MeasurementPrinceton University Press Princeton NJ USA 1988
[22] M Tchatat O Ndoye and R NASI ldquoProduits Forestiers autresque le bois drsquooeuvre (PFAB) place dans lrsquoamenagement durabledes forets denses humides drsquoAfrique Centralerdquo Projet FORA-FRI 88 pages 1999
[23] N Ndam J-P Nkefor and P Blackmore ldquoDomestication ofGnetum africanum and G buchholzianum (Gnetaceae) over-exploited wild forest vegetables of the Central African RegionrdquoSystematics and Geography of Plants vol 71 no 2 pp 739ndash7452001
[24] B A Fonge D A Focho E A Egbe et al ldquoThe effects ofclimate and edaphic factors on plant colonisation of lava flowson Mount Cameroonrdquo Journal of Ecology and the Natural Envi-ronment vol 3 no 6 pp 255ndash267 2011
[25] D Kouame Y C Y Abdou K E Kouassi K E NrsquoGuessanand K Akoi ldquoPreliminary floristic inventory and diversity inAzagny National Park (Cote drsquoIvoire)rdquo European Journal ofScientific Research vol 23 no 4 pp 537ndash547 2008
[26] N Ndam J Healey M Cheek and P Fraser ldquoPlant recovery onthe 1922 and 1959 lava flows on Mount Cameroon CameroonrdquoSystematics andGeography of Plants vol 71 no 2 pp 1023ndash10322001
[27] M Kent and P Coker Vegetation Description and AnalysisBelhaven Press London UK 1992
[28] V B CheM Kervyn G G J Ernst et al ldquoSystematic documen-tation of landslide events in Limbe area (MtCameroonVolcanoSW Cameroon) geometry controlling and triggering factorsrdquoNatural Hazards vol 59 no 1 pp 47ndash74 2011
[29] IUCN Guidelines for Application of IUCN Red List Criteria atRegional Levels Version 30 IUCN Species Survival Commis-sion IUCN Gland Switzerland 2003
[30] R J Scholes and R Biggs Eds Ecosystem Services in SouthernAfrica A Regional Assessment Council for Scientific and Indus-trial Research Pretoria South Africa 2004
[31] P VitousekNutrient Cycling and Limitation Hawirsquoii as a ModelSystem Princeton University Press Princeton NJ USA 2004
[32] K Wada ldquoAllophane and imogoliterdquo in Minerals in Soil Envi-ronment J B Dixon and S B Weed Eds pp 1051ndash1087 SoilScience Society of America Madison Wis USA 2nd edition1989
[33] AMvondo ZeChemical behaviour of IronManganese Zinc andPhosphorus in selected soils of the Bambouto sequence [PhDthesis] University of Ghent Gent Belgium 1991
[34] K Wada and N Gunjigake ldquoActive aluminium iron andphosphate adsorption in andosolsrdquo Soil Science vol 128 pp331ndash336 1981