Research Article Ecological Features of Cultivated …downloads.hindawi.com/journals/ijfr/2014/140926.pdfResearch Article Ecological Features of Cultivated Stands of Aquilaria malaccensis
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Research ArticleEcological Features of Cultivated Stands of Aquilariamalaccensis Lam (Thymelaeaceae) a Vulnerable Tropical TreeSpecies in Assamese Homegardens
P Saikia1 and M L Khan2
1 Centre for Environmental Sciences Central University of Jharkhand Brambe Ranchi Jharkhand 835205 India2Department of Botany Dr Hari Singh Gour Central University Sagar Madhya Pradesh 470003 India
Correspondence should be addressed to P Saikia purabisaikiacujacin
Received 10 February 2014 Accepted 22 June 2014 Published 8 July 2014
Academic Editor Sunil Nautiyal
Copyright copy 2014 P Saikia and M L Khan This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited
Research was conducted in twenty-seven selected villages located in Jorhat and Golaghat districts of upper Assam northeast Indiafor population estimation quantitative ecological analysis and evaluation of Aquilaria malaccensis (Thymelaeaceae) Vegetationsampling was done by quadrat method and A malaccensis is the most dominant tree species in all twenty-seven different studysites of upper Assam contributing 10ndash54 of the total tree density with a mean of 34plusmn2 Density of the species varied from 6236individuals haminus1 to 429 individuals haminus1 with a mean of 1609 individuals haminus1 plusmn 217 whereas frequency of occurrence is very highranging from 93 to 100 with a mean of 98 plusmn 053 in different study sites Distribution of A malaccensis is found contagious inall twenty-six study sites on the basis of abundance to frequency ratio except in KBG Golaghat where its distribution is randomwith 004 abundance to frequency ratio The widespread cultivation of A malaccensis in upper Assam northeast India offers apotential ex situ reservoir for the future conservation and management of this threatened tree
1 Introduction
Aquilaria malaccensis (Thymelaeaceae) locally known asldquoSanchirdquo or ldquoAgarurdquo in Assamese is an evergreen tropicalforest tree highly priced for its resin or agarwoodThe speciesis valued in many cultures for centuries because of its dis-tinctive fragrance and used extensively in incense perfumeand traditional medicine Natural populations of Agaru aredistributed in south and southeast Asia and in India it occursmostly in foothills of northeastern region (Assam ArunachalPradesh Nagaland Meghalaya Mizoram Manipur andTripura) as well as West Bengal [1] However large scaleharvesting of the species from natural population causedrapid depletion in the wild and is listed in Appendix II of theConvention on International Trade in Endangered Speciesof Wild Fauna and Flora (CITES) in 1994 [2] The speciesis ldquovulnerablerdquo globally according to the current IUCN redlist [3] On the other hand Agaru is extensively cultivated inhomegardens of upper Assam and contributes significantly
up to 20 of the total annual income of the family witha mean of 4 plusmn 046 to the economy of the local people[4] A good population stock of Agaru with highest densityand frequency in homegardens of upper Assam was alsoreported by Saikia et al [5] Two distinct morphs of Agaru(Bhola Sanchi and Jati Sanchi) are cultivated in homegardensof upper Assam with different life form characteristics [6]Bhola Sanchi is fast growing and less agarwood yieldingthan the other variant Jati Sanchi which is slow growing buthigh agarwood yielding and preferred for commercial culti-vation Nath and Saikia [7] also reported similar variationsamong the population of Agaru growing in homegarden andthey identified three ldquoracesrdquo from different areas of AssamAccording to them ldquovariant I (RRLJ 2729)rdquo is amedium sizedtree with slender trunk oblong-lanceolate leaves known asBhola Sanchi ldquovariant II (RRLJ 2726)rdquo is a large sized treewithobovate lanceolate leaves known as Sanchi ldquovariant III (RRLJ2730)rdquo is a much branched small to medium sized tree withlanceolate leaves known as Jati Sanchi
Hindawi Publishing CorporationInternational Journal of Forestry ResearchVolume 2014 Article ID 140926 16 pageshttpdxdoiorg1011552014140926
2 International Journal of Forestry Research
Quantitative inventories help in identifying species thatare in different stages of vulnerability as well as various factorsthat influence the existing vegetation in any region [8 9]Considering the scarcity of information on Agaru cultivationin homegardens of upper Assam we attempted to study theecological features mainly the quantitative characteristicsof A malaccensis Lam in homegardens of upper Assamnortheast India
2 Materials and Methods
21 Study Sites The study was conducted in twenty-sevenselected villages located in Jorhat and Golaghat districts ofupper Assam northeast India (25∘481015840 to 27∘101015840N and 93∘171015840to 94∘361015840 E) (Figure 1)The site is surrounded by Sibsagar andDibrugarh districts on the east Nagaon and Karbi Anglongdistricts on the west Lakhimpur and Sonitpur districts onthe north and the bordering state of Nagaland on thesouth The total numbers of villages of Jorhat and Golaghatdistricts are 855 and 1089 with population density of 354and 236 individuals per square kilometer respectively [10]The climate of the study area is classified as tropical typehaving distinct hot and humid summer (340∘C during June-July) and cool winter (100∘C during December-January)The mean annual rainfall of Golaghat and Jorhat districtsranges between 1200mmand 1900mmThe relative humidityremains very high throughout the year [11]
22 Vegetation Analysis A total of twenty-seven differentsites (16 from Golaghat and 11 from Jorhat district) of Jorhatand Golaghat districts of upper Assam northeast India wereselected randomly from the pool of Agaru cultivating areasbased on informal knowledge which roughly representedabout 30 of all Agaru growing areas in the site A totalof 135 homegardens (with a mean of 5 homegardens persite) were selected randomly and studied during 2007ndash2010(Table 1) Vegetation was studied using quadrat methodcovering a minimum of 30 of the area in each homegardenRandom quadrats of 10m times 10m size were used for trees andwithin the same 10m times 10m quadrat one 5m times 5m quadratfor shrubs and two 1m times 1m quadrats for herbs were used inthe studied homegardens Diameter at breast height (DBH)of all the individual trees was recorded during the study at137m above ground Plant species were identified on thebasis of vernacular names published field inventories florasand consulting available herbaria of the region Herbariumspecimens were collected and deposited in the Departmentof Forestry North Eastern Regional Institute of Science andTechnology (Deemed University) Arunachal Pradesh
23 Data Analysis Quantitative analysis of vegetation wasdone following Misra [12] Importance value index (IVI) wascomputed by summing up relative density relative frequencyand relative dominance The species richness was calculatedby using the method ldquoMargalef rsquos index of richnessrdquo (Dmg)[13]
Dmg = (119878 minus 1)ln 119899 (1)
Bhutan Arunachal Pradesh
Assam Nagaland
Meghalaya
Tripura Mizoram
Manipur
Sonitpur and Lakhimpur
Jorhat
Golaghat
Nagaon and Karbi Anglong
Nagaland
Sibsagar
Study areaDistrict boundary
25 125 0
++++ +
++
+
+++++++
++
+++
+
+
+
+
+
+++
N
25km
Figure 1 Map of Golaghat and Jorhat districts of upper Assam NEIndia showing the locations of the study sites
where 119878 = total number of species and 119899 = total number ofindividuals
The Shannon-Wiener Diversity Index [14] was calculatedfrom the IVI values using the formula given byMagurran [13]
119867 = minus
119904
sum
119894=1
119901119894
ln119901119894
(2)
where 119901119894
is the proportion of the IVI of 119894th species and theIVI of all the species (119899
119894
119873)
International Journal of Forestry Research 3
Table 1 Number of studied homegardens and their mean size and number of associated species and dominant tree associate of differentstudied villages
Study sites (villages) HG studied(number) Mean HG area in ha (plusmnSE) Associated species
Concentration of dominance was assessed by SimpsonrsquosIndex [15]
CD =119904
sum
119894=1
(119901119894
)2
(3)
where 119901119894
is the same as for the Shannon-Wiener informationfunction
Evenness index was calculated from Shannon-WienerDiversity Index using the formula
119864 =1198671015840
1198671015840max (4)
where1198671015840 is Shannon-Wiener Diversity Index and1198671015840max =ln 119878 (where 119878 = total number of species)
Soslashrensenrsquos similarity index was calculated using the for-mula given by Sorenson [16]
Soslashrensenrsquos similarity index = 2119862119860 + 119861times 100 (5)
where 119862 is the number of species common to two sites 119860 isthe total number of species in site119860 and119861 is the total numberof species in site 119861
The ratio of abundance to frequency was used to interpretthe distribution pattern of the species [17] The ratio of abun-dance to frequency indicates regular distribution if below0025 random distribution if between 0025 and 005 andcontagious distribution if gt005 [18]
Statistical analysis (Standard error and 119905-test) has beendone using statistical software like MS-Excel and ORIGIN
3 Results
31 Ecological Features of Amalaccensis Amalaccensis is themost dominant tree species in twenty-seven different studysites of upper Assam contributing 10ndash54of total tree densitywith a mean of 34 plusmn 2 Density of the species varied from429 individuals haminus1 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217 Areca catechu L is the mostdominant tree associate in twenty-six different study sites
4 International Journal of Forestry Research
Table 2 Community characteristics of different study sites of upper Assam northeast India
whereasMesua ferrea L was themost dominant tree associatein BMG Jorhat (Table 1) SimilarlyA malaccensis is themostfrequent species followed by A catechu and Bambusa pallidaL and frequency of occurrence ofAmalaccensis ranged from93 to 100 with a mean of 98 plusmn 053 in different studysites 100 frequency was recorded at most of the study sitesincluding BS BMG DG DK ETG HK HCG JTG KWGKNG KG KBG NG NMG PS PFG SMG and SNG Totalbasal cover was the highest (125 cm2 haminus1) in NG Jorhat andthe lowest (034 cm2 haminus1) in JN Golaghat Among differentsites IVI of A malaccensis ranged between 1794 and 7263with a mean of 4936plusmn264 On the other hand abundance ofthe species in different study sites ranged from 4 to 62 with amean of 16plusmn 2 and it was the highest in NMG Golaghat andthe lowest in KBG Golaghat Distribution of A malaccensisis found contagious in all twenty-six study sites on the basisof abundance to frequency ratio except in KBG Golaghatwhere its distribution is random with 004 abundance tofrequency ratio (Table 2)
32 Floristic Composition of Study Sites A total of 323 plantspecies belonging to 241 genera under 95 families consistingof 106 (33) herbs 61 (19) shrubs and 156 (48) trees
were recorded from twenty-seven study sites of upper Assam(Table 5) Although the number of documented trees washigher than that of herbs and shrubs differences were notstatistically significant Overall data showed that familyEuphorbiaceae had the highest number of species (15)followed by Moraceae (13) and Poaceae (12) Species richnesswas very high at all study sites ranging from 63 to 188species with a mean of 113 plusmn 7 but the highest richness wasrecorded from GG Jorhat and the lowest from BMG Jorhat(Table 3) A high variability in density of plant species wasalso noticed in different study sites Tree density was thehighest in NMG Golaghat (13418 individuals haminus1) andthe lowest in BMG Jorhat (1400 individuals haminus1) On theother hand basal area of tree species was the highest inSMG Golaghat (440m2 haminus1) and the lowest in NG Jorhat(054m2 haminus1)
Peak richness index of tree species of 1054 was recordedin KWG Golaghat whereas it was the lowest in DG Jorhat(353) Concentration of dominance (Simpsonrsquos Index) anddiversity (Shannon-Wiener Diversity Index) of tree specieswere showing reverse trend in study sites Concentrationof dominance (Simpsonrsquos Index) of tree species was thehighest in DG Jorhat (012) and the lowest in KBG Golaghat
International Journal of Forestry Research 5
Table 3 Ecological parameters of different populations of A malaccensis (gt318 cm DBH)
(003) on the other hand the highest diversity of treespecies (Shannon-Wiener Diversity Index) was found inKBG Golaghat (378) and it was the lowest in DG Jorhat(252) However species evenness index of tree species rangedfrom 077 to 093 with amean of 086plusmn001 and it was peak inKBG Golaghat and the lowest in KNG Golaghat Soslashrensenrsquossimilarity indices showed a high degree of similarity witha range from 3425 to 7538 among different study sites(Table 4)
4 Discussion
Floristic inventory survey and diversity studies help us tounderstand the species composition and diversity status ofany community [19] A malaccensis is one of the mostdominant tree species in study sites of upper Assam rep-resenting 10ndash54 of the total tree density (with a meanof 34 plusmn 2) showing a trend towards monoculture Ingeneral monoculture has a great impact on species diversityIntroduction of rubber (Hevea brasiliensis) into homegardensresulted in a reduction of species diversity in homegardensof Kerela [20] But this is not evident in the present studyand may be due to the fact that owners tried to produce all
the possible species of common household utilities in theirhomegarden itself
Density of a species provides an index to competitionbetween individuals of the species Higher densities can causegreater competitive stresses leading to poor growth andlower reproductive capacityWe recordedAmalaccensiswithhigh density (429 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217) frequency (93 to 100with a mean of 98 plusmn 053) and abundance (4 to 62 with amean of 16 plusmn 2) One potential explanation of higher densityfrequency and abundance could be extensive cultivation ofthe species in study sites because of its high commercialvalue Total basal cover of trees (gt318 cm DBH) is verylow and ranged from 034 cm2 haminus1 to 125 cm2 haminus1 with amean of 067 cm2 haminus1 plusmn 004 may be because of the highestdensity of lower diameter class individuals of A malaccensisImportance value index (IVI) of the species represents theecological success of any species in a community and it givesan excellent idea about varying environmental factors [21]It provides a complete picture of sociological structure of aspecies because the frequency provides information aboutthe dispersal of a species in an area density gives numericalstrength of the species and dominance represents the basalarea In almost all study sites the highest IVI is contributed
6 International Journal of Forestry Research
Table4Soslashrensenrsquossim
ilarityindex(
)for
different
study
sites
ofup
perA
ssam
northeastIndia
BSBM
GDG
DK
ETG
GP
GG
HBG
HK
HCG
JTG
JNKW
GKN
GKG
KBG
KHG
KHNG
NMG
PSPB
PFG
SPSK
SMG
BS000
BMG
4724
000
DG
563
4925
000
DK
4173
3478
4932
000
ETG
4780
4608
5377
4815
000
GP
4878
4908
5263
4686
5726
000
GG
4365
4940
4942
4563
6079
7506
000
HBG
4505
3425
4868
5181
6178
8387
5490
000
HK
5263
4545
5429
4583
5143
8912
4436
4813
000
HCG
4474
3877
4340
4603
6295
7311
6080
6525
4635
000
JTG
5123
4455
5143
4393
6357
6910
6728
5603
5385
6601
000
JN5029
4828
5385
4731
6032
7844
5552
4978
5333
5455
6480
000
KWG46
35
4483
5000
4180
6968
6000
6667
5714
4790
6246
6623
7000
000
KNG
5100
4422
5217
5024
6498
7731
6049
6614
5171
6267
6545
6397
7148
000
KG4750
5535
5749
4678
5907
7920
6197
5234
5091
5308
5532
6280
6264
6034
000
KBG
5179
4126
4935
4340
6711
6468
6379
5755
5415
6790
7157
6125
6809
6959
5703
000
KHG
5152
3664
7482
4615
4689
9843
4609
4624
4526
3793
4638
4581
4726
4804
5122
4035
000
KH46
49
43478
5625
5102
6412
7957
5825
6109
6105
6175
5769
6034
6138
6226
5622
6192
4974
000
NG
5513
5419
6135
4790
5751
8330
5429
5429
5466
5234
5801
5911
5747
5877
5957
5397
5125
5540
000
NMG5200
4161
4841
4596
4758
9661
4745
5196
5677
5040
5156
5685
5569
5045
5495
5366
4416
5604
5169
000
PS5222
3911
5241
4817
6070
7935
5658
5812
5189
5857
6196
5727
5895
5873
5660
6159
4891
5823
5192
4752
000
PB4926
4356
5143
4486
6286
7137
6177
6381
5192
6601
6978
6880
7013
6836
6298
6689
4541
6154
5541
5689
6118
000
PFG
5419
4545
5185
4819
5862
8221
5448
4976
5375
4706
6087
5347
5846
5639
5882
5578
5786
5377
5792
5311
5797
5565
000
SP4971
5233
5778
4457
6160
7235
6263
5286
5506
5641
6129
5818
6115
5959
6732
6245
4972
5652
6169
5538
5511
6129
5500
000
SK5067
4698
4841
4720
5022
9400
4891
4706
5548
5360
5156
6599
5569
5315
5824
5528
4026
5024
5393
5233
4950
5956
4972
5846
000
SMG
4737
4670
5021
5021
6754
7434
6591
62415064
4024
6667
6109
6547
6667
5385
6852
4483
6737
5781
5440
6143
6469
5412
5861
5040
000
SNG
5380
5059
5955
4176
6210
6725
5627
5689
5909
5756
6179
6239
6377
6173
6404
6442
4914
5702
7538
5389
5561
6179
5960
6667
5389
6125
International Journal of Forestry Research 7
Table 5 Density (individuals haminus1) frequency () abundance and IVI of tree (gt318 cm DBH) shrub and herb species in studiedhomegardens of upper Assam northeast India
Species Family Density (individuals haminus1) Frequency () Abundance IVITrees
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Quantitative inventories help in identifying species thatare in different stages of vulnerability as well as various factorsthat influence the existing vegetation in any region [8 9]Considering the scarcity of information on Agaru cultivationin homegardens of upper Assam we attempted to study theecological features mainly the quantitative characteristicsof A malaccensis Lam in homegardens of upper Assamnortheast India
2 Materials and Methods
21 Study Sites The study was conducted in twenty-sevenselected villages located in Jorhat and Golaghat districts ofupper Assam northeast India (25∘481015840 to 27∘101015840N and 93∘171015840to 94∘361015840 E) (Figure 1)The site is surrounded by Sibsagar andDibrugarh districts on the east Nagaon and Karbi Anglongdistricts on the west Lakhimpur and Sonitpur districts onthe north and the bordering state of Nagaland on thesouth The total numbers of villages of Jorhat and Golaghatdistricts are 855 and 1089 with population density of 354and 236 individuals per square kilometer respectively [10]The climate of the study area is classified as tropical typehaving distinct hot and humid summer (340∘C during June-July) and cool winter (100∘C during December-January)The mean annual rainfall of Golaghat and Jorhat districtsranges between 1200mmand 1900mmThe relative humidityremains very high throughout the year [11]
22 Vegetation Analysis A total of twenty-seven differentsites (16 from Golaghat and 11 from Jorhat district) of Jorhatand Golaghat districts of upper Assam northeast India wereselected randomly from the pool of Agaru cultivating areasbased on informal knowledge which roughly representedabout 30 of all Agaru growing areas in the site A totalof 135 homegardens (with a mean of 5 homegardens persite) were selected randomly and studied during 2007ndash2010(Table 1) Vegetation was studied using quadrat methodcovering a minimum of 30 of the area in each homegardenRandom quadrats of 10m times 10m size were used for trees andwithin the same 10m times 10m quadrat one 5m times 5m quadratfor shrubs and two 1m times 1m quadrats for herbs were used inthe studied homegardens Diameter at breast height (DBH)of all the individual trees was recorded during the study at137m above ground Plant species were identified on thebasis of vernacular names published field inventories florasand consulting available herbaria of the region Herbariumspecimens were collected and deposited in the Departmentof Forestry North Eastern Regional Institute of Science andTechnology (Deemed University) Arunachal Pradesh
23 Data Analysis Quantitative analysis of vegetation wasdone following Misra [12] Importance value index (IVI) wascomputed by summing up relative density relative frequencyand relative dominance The species richness was calculatedby using the method ldquoMargalef rsquos index of richnessrdquo (Dmg)[13]
Dmg = (119878 minus 1)ln 119899 (1)
Bhutan Arunachal Pradesh
Assam Nagaland
Meghalaya
Tripura Mizoram
Manipur
Sonitpur and Lakhimpur
Jorhat
Golaghat
Nagaon and Karbi Anglong
Nagaland
Sibsagar
Study areaDistrict boundary
25 125 0
++++ +
++
+
+++++++
++
+++
+
+
+
+
+
+++
N
25km
Figure 1 Map of Golaghat and Jorhat districts of upper Assam NEIndia showing the locations of the study sites
where 119878 = total number of species and 119899 = total number ofindividuals
The Shannon-Wiener Diversity Index [14] was calculatedfrom the IVI values using the formula given byMagurran [13]
119867 = minus
119904
sum
119894=1
119901119894
ln119901119894
(2)
where 119901119894
is the proportion of the IVI of 119894th species and theIVI of all the species (119899
119894
119873)
International Journal of Forestry Research 3
Table 1 Number of studied homegardens and their mean size and number of associated species and dominant tree associate of differentstudied villages
Study sites (villages) HG studied(number) Mean HG area in ha (plusmnSE) Associated species
Concentration of dominance was assessed by SimpsonrsquosIndex [15]
CD =119904
sum
119894=1
(119901119894
)2
(3)
where 119901119894
is the same as for the Shannon-Wiener informationfunction
Evenness index was calculated from Shannon-WienerDiversity Index using the formula
119864 =1198671015840
1198671015840max (4)
where1198671015840 is Shannon-Wiener Diversity Index and1198671015840max =ln 119878 (where 119878 = total number of species)
Soslashrensenrsquos similarity index was calculated using the for-mula given by Sorenson [16]
Soslashrensenrsquos similarity index = 2119862119860 + 119861times 100 (5)
where 119862 is the number of species common to two sites 119860 isthe total number of species in site119860 and119861 is the total numberof species in site 119861
The ratio of abundance to frequency was used to interpretthe distribution pattern of the species [17] The ratio of abun-dance to frequency indicates regular distribution if below0025 random distribution if between 0025 and 005 andcontagious distribution if gt005 [18]
Statistical analysis (Standard error and 119905-test) has beendone using statistical software like MS-Excel and ORIGIN
3 Results
31 Ecological Features of Amalaccensis Amalaccensis is themost dominant tree species in twenty-seven different studysites of upper Assam contributing 10ndash54of total tree densitywith a mean of 34 plusmn 2 Density of the species varied from429 individuals haminus1 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217 Areca catechu L is the mostdominant tree associate in twenty-six different study sites
4 International Journal of Forestry Research
Table 2 Community characteristics of different study sites of upper Assam northeast India
whereasMesua ferrea L was themost dominant tree associatein BMG Jorhat (Table 1) SimilarlyA malaccensis is themostfrequent species followed by A catechu and Bambusa pallidaL and frequency of occurrence ofAmalaccensis ranged from93 to 100 with a mean of 98 plusmn 053 in different studysites 100 frequency was recorded at most of the study sitesincluding BS BMG DG DK ETG HK HCG JTG KWGKNG KG KBG NG NMG PS PFG SMG and SNG Totalbasal cover was the highest (125 cm2 haminus1) in NG Jorhat andthe lowest (034 cm2 haminus1) in JN Golaghat Among differentsites IVI of A malaccensis ranged between 1794 and 7263with a mean of 4936plusmn264 On the other hand abundance ofthe species in different study sites ranged from 4 to 62 with amean of 16plusmn 2 and it was the highest in NMG Golaghat andthe lowest in KBG Golaghat Distribution of A malaccensisis found contagious in all twenty-six study sites on the basisof abundance to frequency ratio except in KBG Golaghatwhere its distribution is random with 004 abundance tofrequency ratio (Table 2)
32 Floristic Composition of Study Sites A total of 323 plantspecies belonging to 241 genera under 95 families consistingof 106 (33) herbs 61 (19) shrubs and 156 (48) trees
were recorded from twenty-seven study sites of upper Assam(Table 5) Although the number of documented trees washigher than that of herbs and shrubs differences were notstatistically significant Overall data showed that familyEuphorbiaceae had the highest number of species (15)followed by Moraceae (13) and Poaceae (12) Species richnesswas very high at all study sites ranging from 63 to 188species with a mean of 113 plusmn 7 but the highest richness wasrecorded from GG Jorhat and the lowest from BMG Jorhat(Table 3) A high variability in density of plant species wasalso noticed in different study sites Tree density was thehighest in NMG Golaghat (13418 individuals haminus1) andthe lowest in BMG Jorhat (1400 individuals haminus1) On theother hand basal area of tree species was the highest inSMG Golaghat (440m2 haminus1) and the lowest in NG Jorhat(054m2 haminus1)
Peak richness index of tree species of 1054 was recordedin KWG Golaghat whereas it was the lowest in DG Jorhat(353) Concentration of dominance (Simpsonrsquos Index) anddiversity (Shannon-Wiener Diversity Index) of tree specieswere showing reverse trend in study sites Concentrationof dominance (Simpsonrsquos Index) of tree species was thehighest in DG Jorhat (012) and the lowest in KBG Golaghat
International Journal of Forestry Research 5
Table 3 Ecological parameters of different populations of A malaccensis (gt318 cm DBH)
(003) on the other hand the highest diversity of treespecies (Shannon-Wiener Diversity Index) was found inKBG Golaghat (378) and it was the lowest in DG Jorhat(252) However species evenness index of tree species rangedfrom 077 to 093 with amean of 086plusmn001 and it was peak inKBG Golaghat and the lowest in KNG Golaghat Soslashrensenrsquossimilarity indices showed a high degree of similarity witha range from 3425 to 7538 among different study sites(Table 4)
4 Discussion
Floristic inventory survey and diversity studies help us tounderstand the species composition and diversity status ofany community [19] A malaccensis is one of the mostdominant tree species in study sites of upper Assam rep-resenting 10ndash54 of the total tree density (with a meanof 34 plusmn 2) showing a trend towards monoculture Ingeneral monoculture has a great impact on species diversityIntroduction of rubber (Hevea brasiliensis) into homegardensresulted in a reduction of species diversity in homegardensof Kerela [20] But this is not evident in the present studyand may be due to the fact that owners tried to produce all
the possible species of common household utilities in theirhomegarden itself
Density of a species provides an index to competitionbetween individuals of the species Higher densities can causegreater competitive stresses leading to poor growth andlower reproductive capacityWe recordedAmalaccensiswithhigh density (429 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217) frequency (93 to 100with a mean of 98 plusmn 053) and abundance (4 to 62 with amean of 16 plusmn 2) One potential explanation of higher densityfrequency and abundance could be extensive cultivation ofthe species in study sites because of its high commercialvalue Total basal cover of trees (gt318 cm DBH) is verylow and ranged from 034 cm2 haminus1 to 125 cm2 haminus1 with amean of 067 cm2 haminus1 plusmn 004 may be because of the highestdensity of lower diameter class individuals of A malaccensisImportance value index (IVI) of the species represents theecological success of any species in a community and it givesan excellent idea about varying environmental factors [21]It provides a complete picture of sociological structure of aspecies because the frequency provides information aboutthe dispersal of a species in an area density gives numericalstrength of the species and dominance represents the basalarea In almost all study sites the highest IVI is contributed
6 International Journal of Forestry Research
Table4Soslashrensenrsquossim
ilarityindex(
)for
different
study
sites
ofup
perA
ssam
northeastIndia
BSBM
GDG
DK
ETG
GP
GG
HBG
HK
HCG
JTG
JNKW
GKN
GKG
KBG
KHG
KHNG
NMG
PSPB
PFG
SPSK
SMG
BS000
BMG
4724
000
DG
563
4925
000
DK
4173
3478
4932
000
ETG
4780
4608
5377
4815
000
GP
4878
4908
5263
4686
5726
000
GG
4365
4940
4942
4563
6079
7506
000
HBG
4505
3425
4868
5181
6178
8387
5490
000
HK
5263
4545
5429
4583
5143
8912
4436
4813
000
HCG
4474
3877
4340
4603
6295
7311
6080
6525
4635
000
JTG
5123
4455
5143
4393
6357
6910
6728
5603
5385
6601
000
JN5029
4828
5385
4731
6032
7844
5552
4978
5333
5455
6480
000
KWG46
35
4483
5000
4180
6968
6000
6667
5714
4790
6246
6623
7000
000
KNG
5100
4422
5217
5024
6498
7731
6049
6614
5171
6267
6545
6397
7148
000
KG4750
5535
5749
4678
5907
7920
6197
5234
5091
5308
5532
6280
6264
6034
000
KBG
5179
4126
4935
4340
6711
6468
6379
5755
5415
6790
7157
6125
6809
6959
5703
000
KHG
5152
3664
7482
4615
4689
9843
4609
4624
4526
3793
4638
4581
4726
4804
5122
4035
000
KH46
49
43478
5625
5102
6412
7957
5825
6109
6105
6175
5769
6034
6138
6226
5622
6192
4974
000
NG
5513
5419
6135
4790
5751
8330
5429
5429
5466
5234
5801
5911
5747
5877
5957
5397
5125
5540
000
NMG5200
4161
4841
4596
4758
9661
4745
5196
5677
5040
5156
5685
5569
5045
5495
5366
4416
5604
5169
000
PS5222
3911
5241
4817
6070
7935
5658
5812
5189
5857
6196
5727
5895
5873
5660
6159
4891
5823
5192
4752
000
PB4926
4356
5143
4486
6286
7137
6177
6381
5192
6601
6978
6880
7013
6836
6298
6689
4541
6154
5541
5689
6118
000
PFG
5419
4545
5185
4819
5862
8221
5448
4976
5375
4706
6087
5347
5846
5639
5882
5578
5786
5377
5792
5311
5797
5565
000
SP4971
5233
5778
4457
6160
7235
6263
5286
5506
5641
6129
5818
6115
5959
6732
6245
4972
5652
6169
5538
5511
6129
5500
000
SK5067
4698
4841
4720
5022
9400
4891
4706
5548
5360
5156
6599
5569
5315
5824
5528
4026
5024
5393
5233
4950
5956
4972
5846
000
SMG
4737
4670
5021
5021
6754
7434
6591
62415064
4024
6667
6109
6547
6667
5385
6852
4483
6737
5781
5440
6143
6469
5412
5861
5040
000
SNG
5380
5059
5955
4176
6210
6725
5627
5689
5909
5756
6179
6239
6377
6173
6404
6442
4914
5702
7538
5389
5561
6179
5960
6667
5389
6125
International Journal of Forestry Research 7
Table 5 Density (individuals haminus1) frequency () abundance and IVI of tree (gt318 cm DBH) shrub and herb species in studiedhomegardens of upper Assam northeast India
Species Family Density (individuals haminus1) Frequency () Abundance IVITrees
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Concentration of dominance was assessed by SimpsonrsquosIndex [15]
CD =119904
sum
119894=1
(119901119894
)2
(3)
where 119901119894
is the same as for the Shannon-Wiener informationfunction
Evenness index was calculated from Shannon-WienerDiversity Index using the formula
119864 =1198671015840
1198671015840max (4)
where1198671015840 is Shannon-Wiener Diversity Index and1198671015840max =ln 119878 (where 119878 = total number of species)
Soslashrensenrsquos similarity index was calculated using the for-mula given by Sorenson [16]
Soslashrensenrsquos similarity index = 2119862119860 + 119861times 100 (5)
where 119862 is the number of species common to two sites 119860 isthe total number of species in site119860 and119861 is the total numberof species in site 119861
The ratio of abundance to frequency was used to interpretthe distribution pattern of the species [17] The ratio of abun-dance to frequency indicates regular distribution if below0025 random distribution if between 0025 and 005 andcontagious distribution if gt005 [18]
Statistical analysis (Standard error and 119905-test) has beendone using statistical software like MS-Excel and ORIGIN
3 Results
31 Ecological Features of Amalaccensis Amalaccensis is themost dominant tree species in twenty-seven different studysites of upper Assam contributing 10ndash54of total tree densitywith a mean of 34 plusmn 2 Density of the species varied from429 individuals haminus1 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217 Areca catechu L is the mostdominant tree associate in twenty-six different study sites
4 International Journal of Forestry Research
Table 2 Community characteristics of different study sites of upper Assam northeast India
whereasMesua ferrea L was themost dominant tree associatein BMG Jorhat (Table 1) SimilarlyA malaccensis is themostfrequent species followed by A catechu and Bambusa pallidaL and frequency of occurrence ofAmalaccensis ranged from93 to 100 with a mean of 98 plusmn 053 in different studysites 100 frequency was recorded at most of the study sitesincluding BS BMG DG DK ETG HK HCG JTG KWGKNG KG KBG NG NMG PS PFG SMG and SNG Totalbasal cover was the highest (125 cm2 haminus1) in NG Jorhat andthe lowest (034 cm2 haminus1) in JN Golaghat Among differentsites IVI of A malaccensis ranged between 1794 and 7263with a mean of 4936plusmn264 On the other hand abundance ofthe species in different study sites ranged from 4 to 62 with amean of 16plusmn 2 and it was the highest in NMG Golaghat andthe lowest in KBG Golaghat Distribution of A malaccensisis found contagious in all twenty-six study sites on the basisof abundance to frequency ratio except in KBG Golaghatwhere its distribution is random with 004 abundance tofrequency ratio (Table 2)
32 Floristic Composition of Study Sites A total of 323 plantspecies belonging to 241 genera under 95 families consistingof 106 (33) herbs 61 (19) shrubs and 156 (48) trees
were recorded from twenty-seven study sites of upper Assam(Table 5) Although the number of documented trees washigher than that of herbs and shrubs differences were notstatistically significant Overall data showed that familyEuphorbiaceae had the highest number of species (15)followed by Moraceae (13) and Poaceae (12) Species richnesswas very high at all study sites ranging from 63 to 188species with a mean of 113 plusmn 7 but the highest richness wasrecorded from GG Jorhat and the lowest from BMG Jorhat(Table 3) A high variability in density of plant species wasalso noticed in different study sites Tree density was thehighest in NMG Golaghat (13418 individuals haminus1) andthe lowest in BMG Jorhat (1400 individuals haminus1) On theother hand basal area of tree species was the highest inSMG Golaghat (440m2 haminus1) and the lowest in NG Jorhat(054m2 haminus1)
Peak richness index of tree species of 1054 was recordedin KWG Golaghat whereas it was the lowest in DG Jorhat(353) Concentration of dominance (Simpsonrsquos Index) anddiversity (Shannon-Wiener Diversity Index) of tree specieswere showing reverse trend in study sites Concentrationof dominance (Simpsonrsquos Index) of tree species was thehighest in DG Jorhat (012) and the lowest in KBG Golaghat
International Journal of Forestry Research 5
Table 3 Ecological parameters of different populations of A malaccensis (gt318 cm DBH)
(003) on the other hand the highest diversity of treespecies (Shannon-Wiener Diversity Index) was found inKBG Golaghat (378) and it was the lowest in DG Jorhat(252) However species evenness index of tree species rangedfrom 077 to 093 with amean of 086plusmn001 and it was peak inKBG Golaghat and the lowest in KNG Golaghat Soslashrensenrsquossimilarity indices showed a high degree of similarity witha range from 3425 to 7538 among different study sites(Table 4)
4 Discussion
Floristic inventory survey and diversity studies help us tounderstand the species composition and diversity status ofany community [19] A malaccensis is one of the mostdominant tree species in study sites of upper Assam rep-resenting 10ndash54 of the total tree density (with a meanof 34 plusmn 2) showing a trend towards monoculture Ingeneral monoculture has a great impact on species diversityIntroduction of rubber (Hevea brasiliensis) into homegardensresulted in a reduction of species diversity in homegardensof Kerela [20] But this is not evident in the present studyand may be due to the fact that owners tried to produce all
the possible species of common household utilities in theirhomegarden itself
Density of a species provides an index to competitionbetween individuals of the species Higher densities can causegreater competitive stresses leading to poor growth andlower reproductive capacityWe recordedAmalaccensiswithhigh density (429 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217) frequency (93 to 100with a mean of 98 plusmn 053) and abundance (4 to 62 with amean of 16 plusmn 2) One potential explanation of higher densityfrequency and abundance could be extensive cultivation ofthe species in study sites because of its high commercialvalue Total basal cover of trees (gt318 cm DBH) is verylow and ranged from 034 cm2 haminus1 to 125 cm2 haminus1 with amean of 067 cm2 haminus1 plusmn 004 may be because of the highestdensity of lower diameter class individuals of A malaccensisImportance value index (IVI) of the species represents theecological success of any species in a community and it givesan excellent idea about varying environmental factors [21]It provides a complete picture of sociological structure of aspecies because the frequency provides information aboutthe dispersal of a species in an area density gives numericalstrength of the species and dominance represents the basalarea In almost all study sites the highest IVI is contributed
6 International Journal of Forestry Research
Table4Soslashrensenrsquossim
ilarityindex(
)for
different
study
sites
ofup
perA
ssam
northeastIndia
BSBM
GDG
DK
ETG
GP
GG
HBG
HK
HCG
JTG
JNKW
GKN
GKG
KBG
KHG
KHNG
NMG
PSPB
PFG
SPSK
SMG
BS000
BMG
4724
000
DG
563
4925
000
DK
4173
3478
4932
000
ETG
4780
4608
5377
4815
000
GP
4878
4908
5263
4686
5726
000
GG
4365
4940
4942
4563
6079
7506
000
HBG
4505
3425
4868
5181
6178
8387
5490
000
HK
5263
4545
5429
4583
5143
8912
4436
4813
000
HCG
4474
3877
4340
4603
6295
7311
6080
6525
4635
000
JTG
5123
4455
5143
4393
6357
6910
6728
5603
5385
6601
000
JN5029
4828
5385
4731
6032
7844
5552
4978
5333
5455
6480
000
KWG46
35
4483
5000
4180
6968
6000
6667
5714
4790
6246
6623
7000
000
KNG
5100
4422
5217
5024
6498
7731
6049
6614
5171
6267
6545
6397
7148
000
KG4750
5535
5749
4678
5907
7920
6197
5234
5091
5308
5532
6280
6264
6034
000
KBG
5179
4126
4935
4340
6711
6468
6379
5755
5415
6790
7157
6125
6809
6959
5703
000
KHG
5152
3664
7482
4615
4689
9843
4609
4624
4526
3793
4638
4581
4726
4804
5122
4035
000
KH46
49
43478
5625
5102
6412
7957
5825
6109
6105
6175
5769
6034
6138
6226
5622
6192
4974
000
NG
5513
5419
6135
4790
5751
8330
5429
5429
5466
5234
5801
5911
5747
5877
5957
5397
5125
5540
000
NMG5200
4161
4841
4596
4758
9661
4745
5196
5677
5040
5156
5685
5569
5045
5495
5366
4416
5604
5169
000
PS5222
3911
5241
4817
6070
7935
5658
5812
5189
5857
6196
5727
5895
5873
5660
6159
4891
5823
5192
4752
000
PB4926
4356
5143
4486
6286
7137
6177
6381
5192
6601
6978
6880
7013
6836
6298
6689
4541
6154
5541
5689
6118
000
PFG
5419
4545
5185
4819
5862
8221
5448
4976
5375
4706
6087
5347
5846
5639
5882
5578
5786
5377
5792
5311
5797
5565
000
SP4971
5233
5778
4457
6160
7235
6263
5286
5506
5641
6129
5818
6115
5959
6732
6245
4972
5652
6169
5538
5511
6129
5500
000
SK5067
4698
4841
4720
5022
9400
4891
4706
5548
5360
5156
6599
5569
5315
5824
5528
4026
5024
5393
5233
4950
5956
4972
5846
000
SMG
4737
4670
5021
5021
6754
7434
6591
62415064
4024
6667
6109
6547
6667
5385
6852
4483
6737
5781
5440
6143
6469
5412
5861
5040
000
SNG
5380
5059
5955
4176
6210
6725
5627
5689
5909
5756
6179
6239
6377
6173
6404
6442
4914
5702
7538
5389
5561
6179
5960
6667
5389
6125
International Journal of Forestry Research 7
Table 5 Density (individuals haminus1) frequency () abundance and IVI of tree (gt318 cm DBH) shrub and herb species in studiedhomegardens of upper Assam northeast India
Species Family Density (individuals haminus1) Frequency () Abundance IVITrees
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
whereasMesua ferrea L was themost dominant tree associatein BMG Jorhat (Table 1) SimilarlyA malaccensis is themostfrequent species followed by A catechu and Bambusa pallidaL and frequency of occurrence ofAmalaccensis ranged from93 to 100 with a mean of 98 plusmn 053 in different studysites 100 frequency was recorded at most of the study sitesincluding BS BMG DG DK ETG HK HCG JTG KWGKNG KG KBG NG NMG PS PFG SMG and SNG Totalbasal cover was the highest (125 cm2 haminus1) in NG Jorhat andthe lowest (034 cm2 haminus1) in JN Golaghat Among differentsites IVI of A malaccensis ranged between 1794 and 7263with a mean of 4936plusmn264 On the other hand abundance ofthe species in different study sites ranged from 4 to 62 with amean of 16plusmn 2 and it was the highest in NMG Golaghat andthe lowest in KBG Golaghat Distribution of A malaccensisis found contagious in all twenty-six study sites on the basisof abundance to frequency ratio except in KBG Golaghatwhere its distribution is random with 004 abundance tofrequency ratio (Table 2)
32 Floristic Composition of Study Sites A total of 323 plantspecies belonging to 241 genera under 95 families consistingof 106 (33) herbs 61 (19) shrubs and 156 (48) trees
were recorded from twenty-seven study sites of upper Assam(Table 5) Although the number of documented trees washigher than that of herbs and shrubs differences were notstatistically significant Overall data showed that familyEuphorbiaceae had the highest number of species (15)followed by Moraceae (13) and Poaceae (12) Species richnesswas very high at all study sites ranging from 63 to 188species with a mean of 113 plusmn 7 but the highest richness wasrecorded from GG Jorhat and the lowest from BMG Jorhat(Table 3) A high variability in density of plant species wasalso noticed in different study sites Tree density was thehighest in NMG Golaghat (13418 individuals haminus1) andthe lowest in BMG Jorhat (1400 individuals haminus1) On theother hand basal area of tree species was the highest inSMG Golaghat (440m2 haminus1) and the lowest in NG Jorhat(054m2 haminus1)
Peak richness index of tree species of 1054 was recordedin KWG Golaghat whereas it was the lowest in DG Jorhat(353) Concentration of dominance (Simpsonrsquos Index) anddiversity (Shannon-Wiener Diversity Index) of tree specieswere showing reverse trend in study sites Concentrationof dominance (Simpsonrsquos Index) of tree species was thehighest in DG Jorhat (012) and the lowest in KBG Golaghat
International Journal of Forestry Research 5
Table 3 Ecological parameters of different populations of A malaccensis (gt318 cm DBH)
(003) on the other hand the highest diversity of treespecies (Shannon-Wiener Diversity Index) was found inKBG Golaghat (378) and it was the lowest in DG Jorhat(252) However species evenness index of tree species rangedfrom 077 to 093 with amean of 086plusmn001 and it was peak inKBG Golaghat and the lowest in KNG Golaghat Soslashrensenrsquossimilarity indices showed a high degree of similarity witha range from 3425 to 7538 among different study sites(Table 4)
4 Discussion
Floristic inventory survey and diversity studies help us tounderstand the species composition and diversity status ofany community [19] A malaccensis is one of the mostdominant tree species in study sites of upper Assam rep-resenting 10ndash54 of the total tree density (with a meanof 34 plusmn 2) showing a trend towards monoculture Ingeneral monoculture has a great impact on species diversityIntroduction of rubber (Hevea brasiliensis) into homegardensresulted in a reduction of species diversity in homegardensof Kerela [20] But this is not evident in the present studyand may be due to the fact that owners tried to produce all
the possible species of common household utilities in theirhomegarden itself
Density of a species provides an index to competitionbetween individuals of the species Higher densities can causegreater competitive stresses leading to poor growth andlower reproductive capacityWe recordedAmalaccensiswithhigh density (429 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217) frequency (93 to 100with a mean of 98 plusmn 053) and abundance (4 to 62 with amean of 16 plusmn 2) One potential explanation of higher densityfrequency and abundance could be extensive cultivation ofthe species in study sites because of its high commercialvalue Total basal cover of trees (gt318 cm DBH) is verylow and ranged from 034 cm2 haminus1 to 125 cm2 haminus1 with amean of 067 cm2 haminus1 plusmn 004 may be because of the highestdensity of lower diameter class individuals of A malaccensisImportance value index (IVI) of the species represents theecological success of any species in a community and it givesan excellent idea about varying environmental factors [21]It provides a complete picture of sociological structure of aspecies because the frequency provides information aboutthe dispersal of a species in an area density gives numericalstrength of the species and dominance represents the basalarea In almost all study sites the highest IVI is contributed
6 International Journal of Forestry Research
Table4Soslashrensenrsquossim
ilarityindex(
)for
different
study
sites
ofup
perA
ssam
northeastIndia
BSBM
GDG
DK
ETG
GP
GG
HBG
HK
HCG
JTG
JNKW
GKN
GKG
KBG
KHG
KHNG
NMG
PSPB
PFG
SPSK
SMG
BS000
BMG
4724
000
DG
563
4925
000
DK
4173
3478
4932
000
ETG
4780
4608
5377
4815
000
GP
4878
4908
5263
4686
5726
000
GG
4365
4940
4942
4563
6079
7506
000
HBG
4505
3425
4868
5181
6178
8387
5490
000
HK
5263
4545
5429
4583
5143
8912
4436
4813
000
HCG
4474
3877
4340
4603
6295
7311
6080
6525
4635
000
JTG
5123
4455
5143
4393
6357
6910
6728
5603
5385
6601
000
JN5029
4828
5385
4731
6032
7844
5552
4978
5333
5455
6480
000
KWG46
35
4483
5000
4180
6968
6000
6667
5714
4790
6246
6623
7000
000
KNG
5100
4422
5217
5024
6498
7731
6049
6614
5171
6267
6545
6397
7148
000
KG4750
5535
5749
4678
5907
7920
6197
5234
5091
5308
5532
6280
6264
6034
000
KBG
5179
4126
4935
4340
6711
6468
6379
5755
5415
6790
7157
6125
6809
6959
5703
000
KHG
5152
3664
7482
4615
4689
9843
4609
4624
4526
3793
4638
4581
4726
4804
5122
4035
000
KH46
49
43478
5625
5102
6412
7957
5825
6109
6105
6175
5769
6034
6138
6226
5622
6192
4974
000
NG
5513
5419
6135
4790
5751
8330
5429
5429
5466
5234
5801
5911
5747
5877
5957
5397
5125
5540
000
NMG5200
4161
4841
4596
4758
9661
4745
5196
5677
5040
5156
5685
5569
5045
5495
5366
4416
5604
5169
000
PS5222
3911
5241
4817
6070
7935
5658
5812
5189
5857
6196
5727
5895
5873
5660
6159
4891
5823
5192
4752
000
PB4926
4356
5143
4486
6286
7137
6177
6381
5192
6601
6978
6880
7013
6836
6298
6689
4541
6154
5541
5689
6118
000
PFG
5419
4545
5185
4819
5862
8221
5448
4976
5375
4706
6087
5347
5846
5639
5882
5578
5786
5377
5792
5311
5797
5565
000
SP4971
5233
5778
4457
6160
7235
6263
5286
5506
5641
6129
5818
6115
5959
6732
6245
4972
5652
6169
5538
5511
6129
5500
000
SK5067
4698
4841
4720
5022
9400
4891
4706
5548
5360
5156
6599
5569
5315
5824
5528
4026
5024
5393
5233
4950
5956
4972
5846
000
SMG
4737
4670
5021
5021
6754
7434
6591
62415064
4024
6667
6109
6547
6667
5385
6852
4483
6737
5781
5440
6143
6469
5412
5861
5040
000
SNG
5380
5059
5955
4176
6210
6725
5627
5689
5909
5756
6179
6239
6377
6173
6404
6442
4914
5702
7538
5389
5561
6179
5960
6667
5389
6125
International Journal of Forestry Research 7
Table 5 Density (individuals haminus1) frequency () abundance and IVI of tree (gt318 cm DBH) shrub and herb species in studiedhomegardens of upper Assam northeast India
Species Family Density (individuals haminus1) Frequency () Abundance IVITrees
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
(003) on the other hand the highest diversity of treespecies (Shannon-Wiener Diversity Index) was found inKBG Golaghat (378) and it was the lowest in DG Jorhat(252) However species evenness index of tree species rangedfrom 077 to 093 with amean of 086plusmn001 and it was peak inKBG Golaghat and the lowest in KNG Golaghat Soslashrensenrsquossimilarity indices showed a high degree of similarity witha range from 3425 to 7538 among different study sites(Table 4)
4 Discussion
Floristic inventory survey and diversity studies help us tounderstand the species composition and diversity status ofany community [19] A malaccensis is one of the mostdominant tree species in study sites of upper Assam rep-resenting 10ndash54 of the total tree density (with a meanof 34 plusmn 2) showing a trend towards monoculture Ingeneral monoculture has a great impact on species diversityIntroduction of rubber (Hevea brasiliensis) into homegardensresulted in a reduction of species diversity in homegardensof Kerela [20] But this is not evident in the present studyand may be due to the fact that owners tried to produce all
the possible species of common household utilities in theirhomegarden itself
Density of a species provides an index to competitionbetween individuals of the species Higher densities can causegreater competitive stresses leading to poor growth andlower reproductive capacityWe recordedAmalaccensiswithhigh density (429 to 6236 individuals haminus1 with a meanof 1609 individuals haminus1 plusmn 217) frequency (93 to 100with a mean of 98 plusmn 053) and abundance (4 to 62 with amean of 16 plusmn 2) One potential explanation of higher densityfrequency and abundance could be extensive cultivation ofthe species in study sites because of its high commercialvalue Total basal cover of trees (gt318 cm DBH) is verylow and ranged from 034 cm2 haminus1 to 125 cm2 haminus1 with amean of 067 cm2 haminus1 plusmn 004 may be because of the highestdensity of lower diameter class individuals of A malaccensisImportance value index (IVI) of the species represents theecological success of any species in a community and it givesan excellent idea about varying environmental factors [21]It provides a complete picture of sociological structure of aspecies because the frequency provides information aboutthe dispersal of a species in an area density gives numericalstrength of the species and dominance represents the basalarea In almost all study sites the highest IVI is contributed
6 International Journal of Forestry Research
Table4Soslashrensenrsquossim
ilarityindex(
)for
different
study
sites
ofup
perA
ssam
northeastIndia
BSBM
GDG
DK
ETG
GP
GG
HBG
HK
HCG
JTG
JNKW
GKN
GKG
KBG
KHG
KHNG
NMG
PSPB
PFG
SPSK
SMG
BS000
BMG
4724
000
DG
563
4925
000
DK
4173
3478
4932
000
ETG
4780
4608
5377
4815
000
GP
4878
4908
5263
4686
5726
000
GG
4365
4940
4942
4563
6079
7506
000
HBG
4505
3425
4868
5181
6178
8387
5490
000
HK
5263
4545
5429
4583
5143
8912
4436
4813
000
HCG
4474
3877
4340
4603
6295
7311
6080
6525
4635
000
JTG
5123
4455
5143
4393
6357
6910
6728
5603
5385
6601
000
JN5029
4828
5385
4731
6032
7844
5552
4978
5333
5455
6480
000
KWG46
35
4483
5000
4180
6968
6000
6667
5714
4790
6246
6623
7000
000
KNG
5100
4422
5217
5024
6498
7731
6049
6614
5171
6267
6545
6397
7148
000
KG4750
5535
5749
4678
5907
7920
6197
5234
5091
5308
5532
6280
6264
6034
000
KBG
5179
4126
4935
4340
6711
6468
6379
5755
5415
6790
7157
6125
6809
6959
5703
000
KHG
5152
3664
7482
4615
4689
9843
4609
4624
4526
3793
4638
4581
4726
4804
5122
4035
000
KH46
49
43478
5625
5102
6412
7957
5825
6109
6105
6175
5769
6034
6138
6226
5622
6192
4974
000
NG
5513
5419
6135
4790
5751
8330
5429
5429
5466
5234
5801
5911
5747
5877
5957
5397
5125
5540
000
NMG5200
4161
4841
4596
4758
9661
4745
5196
5677
5040
5156
5685
5569
5045
5495
5366
4416
5604
5169
000
PS5222
3911
5241
4817
6070
7935
5658
5812
5189
5857
6196
5727
5895
5873
5660
6159
4891
5823
5192
4752
000
PB4926
4356
5143
4486
6286
7137
6177
6381
5192
6601
6978
6880
7013
6836
6298
6689
4541
6154
5541
5689
6118
000
PFG
5419
4545
5185
4819
5862
8221
5448
4976
5375
4706
6087
5347
5846
5639
5882
5578
5786
5377
5792
5311
5797
5565
000
SP4971
5233
5778
4457
6160
7235
6263
5286
5506
5641
6129
5818
6115
5959
6732
6245
4972
5652
6169
5538
5511
6129
5500
000
SK5067
4698
4841
4720
5022
9400
4891
4706
5548
5360
5156
6599
5569
5315
5824
5528
4026
5024
5393
5233
4950
5956
4972
5846
000
SMG
4737
4670
5021
5021
6754
7434
6591
62415064
4024
6667
6109
6547
6667
5385
6852
4483
6737
5781
5440
6143
6469
5412
5861
5040
000
SNG
5380
5059
5955
4176
6210
6725
5627
5689
5909
5756
6179
6239
6377
6173
6404
6442
4914
5702
7538
5389
5561
6179
5960
6667
5389
6125
International Journal of Forestry Research 7
Table 5 Density (individuals haminus1) frequency () abundance and IVI of tree (gt318 cm DBH) shrub and herb species in studiedhomegardens of upper Assam northeast India
Species Family Density (individuals haminus1) Frequency () Abundance IVITrees
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Table 5 Density (individuals haminus1) frequency () abundance and IVI of tree (gt318 cm DBH) shrub and herb species in studiedhomegardens of upper Assam northeast India
Species Family Density (individuals haminus1) Frequency () Abundance IVITrees
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Table 5 Density (individuals haminus1) frequency () abundance and IVI of tree (gt318 cm DBH) shrub and herb species in studiedhomegardens of upper Assam northeast India
Species Family Density (individuals haminus1) Frequency () Abundance IVITrees
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Brassica oleracea L var botrytis L Brassicaceae 515 059 867 020Brassica oleracea L var capitata L Brassicaceae 608 073 836 024Brassica oleracea L var gongylodes L Brassicaceae 872 112 776 036Bryophyllum pinnatum Lam Crassulaceae 1849 443 418 108Cannabis sativa L Cannabaceae 661 152 435 038Carex sp Cyperaceae 211 046 457 012Catharanthus roseus L Apocynaceae 211 079 267 017Celosia sp Amaranthaceae 159 053 300 012Centella asiatica (L) Urban Apiaceae 7325 1380 531 369Chenopodium album L Chenopodiaceae 251 086 292 019Chrysopogon aciculatus (Retz) Trin Poaceae 6532 376 1735 195Cleome viscosa L Capparaceae 192 079 242 016Clitoria ternatea L Papilionaceae 46 040 117 007Coccinia cordifolia (L) Cogn Cucurbitaceae 185 092 200 018Coleus sp Lamiaceae 159 033 480 008Colocasia esculenta (L) Schott Araceae 13349 2094 638 606Commelina benghalensis L Commelinaceae 4505 872 517 230Coriandrum sativum L Apiaceae 1572 059 2644 042Costus speciosus (Koen ex Retz) Smith Costaceae 159 066 240 014Crassocephalum crepidioides (Benth) Moore Asteraceae 462 125 368 029Cucumis sativus L Cucurbitaceae 159 046 343 011Cucurbita pepo L Cucurbitaceae 297 132 225 027Cuphea carthagenensis (Jacq) JF Macbr Lythraceae 1955 383 510 101Curcuma longa L Zingiberaceae 4914 343 1431 156Cynodon dactylon (L) Pers Poaceae 20086 1929 1041 721Cyperus brevifolius (Rottb) Endl ex Hassk Cyperaceae 3554 608 585 169Cyperus rotundus L Cyperaceae 14650 2034 720 624Cyperus sp Cyperaceae 6968 1341 520 355Daucus carota L var sativa DC Apiaceae 1770 099 1787 052Desmodium elegans DC Papilionaceae 26 013 200 003Dioscorea alata L Dioscoreaceae 476 211 225 043Dioscorea deltoideaWall Dioscoreaceae 40 026 150 005Diplazium esculentum (Retz) Sw Athyriaceae 1830 476 385 113Dolichos lablab L Papilionaceae 132 079 167 015
International Journal of Forestry Research 13
Table 5 Continued
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Species Family Density (individuals haminus1) Frequency () Abundance IVIDrymaria cordata (L) Wild ex Roemer andSchultes Caryophyllaceae 7919 951 833 314
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
Species Family Density (individuals haminus1) Frequency () Abundance IVISolanum tuberosum L Solanaceae 1202 046 2600 032Spilanthes paniculataWall ex DC Asteraceae 10416 1664 626 478Spinacia oleracea L Chenopodiaceae 852 125 679 037Tagetes patula L Asteraceae 1466 376 389 089Vigna sinensis (L) Savi ex Hassk Papilionaceae 218 086 254 018Zingiber officinale Roscoe Zingiberaceae 1731 112 1541 054lowastLocale name
by A malaccensis which is ranged from 1794 to 7263 witha mean of 4936 plusmn 264 Dispersal limitation is an importantecological factor for controlling species distribution pattern[22] Contagious distribution has been accepted as a char-acteristic pattern of plant occurrence in nature [23] and itis an indication of clusteredness Contagious distribution ofA malaccensis is found in all study sites except in KBGGolaghat where its distribution is random with abundanceto frequency ratio of 004 Contagious distribution of allthe species irrespective of their habit in homegardens ofnortheast India is also reported by Sahoo et al [24]
Ecological and socioeconomic factors including geo-graphic location climate water availability garden sizeand history agricultural policy market needs food cultureand household preferences influence the species diversityof traditional homegardens [25ndash27] Needs and interest ofhomegarden owners may also play a vital role in regulatingfloristic compositions of homegardens apart from edaphiccultural and socioeconomic factors [5] Species richnessprovides an easily comprehensible expression of diversitywhich is affected by long term factors like community stabilityand evolutionary time as the heterogeneity of micro- andmacroenvironments impact on the diversification of differentcommunities [28] Our investigation recorded 323 plantspecies (156 trees 61 shrubs and 106 herbs) indicating ahigh species richness of the study site It is much higherthan the earlier reports from Assam [29] as well as otherparts of the world [30 31] This may be due to the diversecultural practices of the region and prevailing microclimaticconditions which provide suitable growing conditions fordifferent plant species Constituent of high floristic diversity isperhaps the potential of homegardens to serve as repositoriesof genetic diversity [5] Very high species richness at allstudy sites is recorded in the present study ranging from63 to 188 species with a mean of 113 plusmn 7 which is muchhigher than the earlier report from other parts of the world[25 32] Although tree density (1400 to 13418 individualshaminus1) in different study sites was much higher than therecorded tree density in homegardens of other parts of India[29 31] the basal cover of tree species (054 to 440m2 haminus1)was much lesser than earlier report from Assam [29] Thismay be due to the dominance of narrow range diameterclass species in the study sites of upper Assam northeastIndia
Higher species richness indices (353 to 1054) and speciesevenness indices (077 to 093) represent the floristic richness
of all the study sites of upper Assam northeast IndiaShannon-Wiener diversity index is generally high for tropicalforests of Indian subcontinent and ranged from 081 to 41[33ndash36] Shannon-Wiener diversity indices ranging from 252to 378 represent the same structure of study sites of upperAssam and tropical forests of Indian subcontinent Differ-ences in species diversity between communities generallyresulted from variations in site specificity [37] Moreover itis often correlated with rainfall and nutrient status of the site[38] Although species diversity was high the high similarityindices (3425 to 7538) among different study sitesindicate that floristic composition is characteristically similarin the region may be because of common cultural interestof household owners High diversity and low concentrationdominance in study sites may be due to different levels ofanthropogenic pressure in different sites
5 Conclusions
Thewidespread cultivation ofAmalaccensis in upper Assamnortheast India offers a potential ex situ reservoir for thefuture conservation and management of this threatened treeHowever genetic diversity of such rare species of forest originmay be affected in managed ecosystems due to limited geneflow inbreeding and selection pressure A thorough investi-gation of the genetic variation of the A malaccensis cultiva-tions investigated here is needed before their potential valueto the ex situ conservation of this species can be confirmed
Conflict of Interests
The authors (Dr P Saikia and Professor M L Khan) declarethat there is no conflict of interests regarding the publicationof this paper
Acknowledgments
The authors would like to express their sincere gratitudetowards the people of upper Assam for the free access to theirhomegardens for their cooperation during the survey andinterviews and for the permission to collect plant samplesFinancial support from DBT Govt of India through theproject ldquoMapping and quantitative assessment of geographicdistribution and population status of plant resources ofEastern Himalayan regionrdquo is highly acknowledged
International Journal of Forestry Research 15
References
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980
[1] Anonymous ldquoReview of Significant Trade Aquilaria malac-censisrdquo httpwwwcitesorgsitesdefaultfilesengcompc14E-PC14-09-02-02-A2pdf
[2] CITES ldquoResolutionrdquo in Proceedings of the 9th Meeting of theConference of the Parties (COP rsquo94) Fort Lauderdale Fla USANovember 1994
[3] IUCN Asian Regional Workshop (Conservation amp SustainableManagement of Trees Viet Nam) 1998 Aquilaria malaccensisIn IUCN 2009 IUCN Red List of Threatened Species Version20092 2010 httpwwwiucnredlistorg
[4] P Saikia and M L Khan ldquoAgar (Aquilaria malaccensis Lam)a promising crop in the homegardens of Upper Assam North-eastern Indiardquo Journal of Tropical Agriculture vol 50 pp 8ndash142011
[5] P Saikia B I Choudhury and M L Khan ldquoFloristic compo-sition and plant utilization pattern in homegardens of UpperAssam Indiardquo Tropical Ecology vol 53 no 1 pp 105ndash118 2012
[6] P Saikia and M L Khan ldquoAquilaria malaccensis Lam a Red-listed and highly exploited tree species in the Assamese homegardenrdquo Current Science vol 102 no 4 pp 546ndash547 2012
[7] S C Nath and N Saikia ldquoIndigenous knowledge on utility andutilitarian aspects of Aquilaria malaccensis Lamk in northeastIndiardquo Indian Journal of Traditional Knowledge vol 1 no 1 pp47ndash58 2002
[8] N Parthasarathy ldquoTree diversity and distribution in undis-turbed and human-impacted sites of tropical wet evergreenforest in southern Western Ghats Indiardquo Biodiversity and Con-servation vol 8 no 10 pp 1365ndash1381 1999
[9] H Padalia N Chauhan M C Porwal and P S Roy ldquoPhytoso-ciological observations on tree species diversity of AndamanIslands IndiardquoCurrent Science vol 87 no 6 pp 799ndash806 2004
[10] Census of India Census Report Ministry of Home AffairsGovernment of India 2001
[11] P Saikia Population structure and conservation practices ofAquilaria malaccensis Lam in homegardens of upper Assamand its prospects in socio-economic development [PhD thesis]Department of Forestry NERIST (DeemedUniversity) Aruna-chal Pradesh India 2011
[12] R Misra Ecology Workbook Oxford amp IBH Publishing Com-pany Calcutta India 1968
[13] A F Magurran Ecological Diversity and Its Measurement Prin-ceton University Press Princeton NJ USA 1988
[14] C E Shannon andWWienerTheMathematicalTheory of Com-munities University of Illinois Press Urbana Ill USA 1963
[15] E H Simpson ldquoMeasurement of diversityrdquo Nature vol 163article 688 1949
[16] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 pp 1ndash34 1948
[17] W GWhitford ldquoDistribution of woodland plants in relation tosuccession and clonal growthrdquo Ecology vol 30 no 2 pp 199ndash208 1949
[18] J T Curtis andG CottamPlant EcologyWork Book LaboratoryField Reference Manual Burgess Minneapolis Minn USA1956
[19] J E Gordon and A C Newton ldquoEfficient floristic inventory forthe assessment of tropical tree diversity a comparative test of
four alternative approachesrdquo Forest Ecology and Managementvol 237 no 1ndash3 pp 564ndash573 2006
[20] D Jose ldquoStructure and productivity of the homegardens ofKerala a case studyrdquo in Proceeding of the 4th Kerala ScienceCongress C G R Nair Ed pp 17ndash19 Science Technology andEnvironmentDepartment Government of KeralaThiruvanan-thapuram India 1992
[21] E P Odum Ecology Holt Reinhart and Winston New YorkNY USA 2005
[22] S PHubbell R B Foster S T OrsquoBrien et al ldquoLight-gap disturb-ances recruitment limitation and tree diversity in a neotropicalforestrdquo Science vol 283 no 5401 pp 554ndash557 1999
[23] H T Odum Fundamentals of Ecology WB Saunders Phiadel-phia Pa USA 1971
[24] U K Sahoo P Rocky K Vanlalhriatpuia and K UpadhyayaldquoStructural diversity and functional dynamism of traditionalhome gardens of North-East IndiardquoThe Bioscan vol 1 pp 159ndash171 2010
[25] L N Trinh J W Watson N N Hue et al ldquoAgrobiodiversityconservation and development in Vietnamese home gardensrdquoAgriculture Ecosystems and Environment vol 97 no 1ndash3 pp317ndash344 2003
[26] K Kehlenbeck and B L Maass ldquoCrop diversity and classifi-cation of homegardens in Central Sulawesi Indonesiardquo Agro-forestry Systems vol 63 no 1 pp 53ndash62 2005
[27] O T Coomes and N Ban ldquoCultivated plant species diversity inhome gardens of an amazonian peasant village in NortheasternPerurdquo Economic Botany vol 58 no 3 pp 420ndash434 2004
[28] R K Verma K S Kapoor S P Subramani and R S RawatldquoEvaluation of plant diversity and soil quality under plantationraised in surfacemined areasrdquo Indian Journal of Forestry vol 27no 2 pp 227ndash233 2004
[29] T Das and A K Das ldquoInventorying plant biodiversity in home-gardens a case study in Barak Valley Assam North East IndiardquoCurrent Science vol 89 no 1 pp 155ndash163 2005
[30] C Padoch and W de Jong ldquoThe house gardens of Santa Rosadiversity and variability in an amazonian agricultural systemrdquoEconomic Botany vol 45 no 2 pp 166ndash175 1991
[31] BM Kumar S J George and S Chinnamani ldquoDiversity struc-ture and standing stock of wood in the homegardens of Keralain peninsular IndiardquoAgroforestry Systems vol 25 no 3 pp 243ndash262 1994
[32] Z L Dao W S Chen H J Guo H L Duan and J G DuanldquoHousehold based agrobiodiversity assessment (HH-ABA) ofhouse garden inHanlong village of Baosha east slope of Gaolig-ong Mountainsrdquo Acta Botanica Yunnanica supplement 12 pp102ndash112 2000 (Chinese)
[33] P Bhuyan M L Khan and R S Tripathi ldquoTree diversityand population structure in undisturbed and human-impactedstands of tropical wet evergreen forest in Arunachal PradeshEastern Himalayas Indiardquo Biodiversity and Conservation vol12 no 8 pp 1753ndash1773 2003
[34] N Parthasarathy V Kinhal and L P Kumar ldquoPlant speciesdiversity and human impacts in the tropical wet evergreenforests of southern Western Ghatsrdquo in Proceedings of the Indo-French Workshop on Tropical Forest Ecosystems Natural Func-tioning and Anthropogenic Impact pp 26ndash27 French InstitutePuducherry India November 1992
[35] J S Singh Y S Rawat and O P Chaturvedi ldquoReplacement ofoak forest with pine in the Himalaya affects the nitrogen cyclerdquoNature vol 311 no 5981 pp 54ndash56 1984
16 International Journal of Forestry Research
[36] NVisalakshi ldquoVegetation analysis of two tropical dry evergreenforests in southern IndiardquoTropical Ecology vol 36 no 1 pp 117ndash127 1995
[37] J S Denslow ldquoGap partitioning among tropical rainforest treesrdquoBiotropica vol 12 no 2 pp 47ndash55 1980
[38] G S Hartshorn ldquoNeotropical forest dynamicsrdquo Biotropica vol12 no 2 supplement pp 23ndash30 1980