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RESEARCH Multiple-purposes Land Mapping and Resources Inventory
SILVIA DIANA MATTEUCCI Universidad Nacional Experimental Francisco
de Miranda Coro, Venezuela
AiDA COLMA Universidad Nacional Experimental Francisco de
Miranda Coro, Venezuela
LAURA PLA* Escuela de Postgrado Facultad de Agronomia, UCV
Maracay, Venezuela
ABSTRACT / A land classification and resources inventory of
Falc6n State was underiaken with the aim of gathering base- line
information to help in development planning. The study
area, located in northwestern Venezuela, comprises an eco-
logically diverse region, due both to its varied geomorphology and
to its history of human occupation. A landscape approach was used.
Qn the basis of photointerpretation, examination of existing
literature, and field work, uniform land units (physiog- nomic
units) were delineated and described in terms of land- form, soil,
vegetation, drainage pattern, and climate. These were grouped in
homogeneous units (HU) on the basis of their potential natural
vegetation through the delimitation of climax complexes. The last
hierarchy, the land systems, comprise the geomorphogenetically
related HU. The results are presented at different levels of
generalization and integration, in verbal and cartographic
descriptions, and they are stored in stan- dardized formats to
ensure ease of comprehension and han- dling and to meet different
needs. This report describes the methods employed for the survey
and data presentation, and discusses its applicability and
limitations.
FalcOn State, in northwestern Venezuela, comprises 24,750 km 2
of a mosaic of landscapes whose intricacy is due to the extreme
variations in relief and topography and to the history of human
occupation. An inventory of land types and natural resources was
required to serve as a basis for land-use planning at the state
level. Because there was scarce and scattered previous information,
a reduced research team, an intricately dissected landscape,
availability of fairly recent photoeoverage and good cartographic
sheets at scale 1/100,000, and the need to give an answer in a
short time, a landscape approach (Mabbutt 1968) was selected.
The integrated approach, introduced by Christian and Stewart
(1953), and applied since then to various situations (UNESCO 1968,
Stewart 1968, FAO 1976, Jurdant and others 1974, Beckett and others
1972) has proved adequate for the study of undeveloped regions. The
method is based on the concept that it is possible to identify
recurring land-units of similar genesis, charac- terized by
distinctive topography, vegetation, and soils. These land-units can
be assembled in land systems on the basis of their geographic and
genetic relationships (Christian 1958). The correlations between
topography, vegetation, and soils arise from a long history of
land-
KEY WORDS: Land classification; Topography; Natural resources
inventory
*Present address: Universidad Nacional Experimental Francisco de
Miranda, Coro, Venezuela.
scape formation (Christian 1952). In regions in which human
activity has partially changed the natural vegeta- tion, land-units
can be assigned to the correct category by extrapolation of natural
vegetation remnants to culti- vated neighbouring segments of
similar landform, soils and relationships to other landforms
(Christian 1958). In regions with a long history of human
occupation, the patterns that result from land use may be
correlated with landform and soils. In such cases, recognition of
land- units and land systems is done through the identification of
those patterns (Christian and Stewart 1968, Satyana- rayan and
Dhruvanarayan 1968).
Falc6n State is in an intermediate situation, in which land use
has been extensive but recent. Thus, it is not imprinted in the
landscape. Shifting agriculture has caused a gamut of seral stages,
and has been so intense and inadequate to natural environmental
conditions, that natural vegetation remnants are almost absent.
Accord- ingly, the basic methodology was modified to meet the local
conditions and needs.
This article describes the methods employed to obtain a
hierarchical classification of the land and a natural resources
inventory, it shows examples of the formats used for presentation
of results, and it discusses the applicability and limitations of
the results obtained.
The Study Area
Falc6n State is located in northwestern Venezuela, between
latitudes 10o18 ' and 12o13 ' N, and longitudes
Environmental Management Vol. 9, No. 3, pp. 231-242 9 1985
Springer-Verlag New York Inc.
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232 s.O. Matteucci and others
70=00 9
........ ~ FALCON STATE, VENEZUELA
( " ~ J '~' / ,,' P~AGUA,*' /
" E'S'E22R,.,ME. I . , , .# / /A / / / / ! , / / : /
,,._..,,_.~ ---~. - KM ~ SEMIARID ZONE .~,.. LIMIT between
ZONES
LIMIT between PROVINCES . d [----'7 SUBHUMIO ZONE
Figure l. Physiographic provinces and climatic zones in Falc6n
State, Venezuela.
68~ and 71~ W. Topographic diversity results in heterogeneous
hydrological conditions and in a mosaic of landscapes arranged in a
parallel pattern in an ENE- WSW direction. Five physiographic
provinces occupy the territory: the Coastal Plains, the Coastal
Piedmont, Falc6n Ranges, the Central Valleys, and the Eastern
Maritime Valleys (Figure 1).
Geology and Geomorphology Most of Falc6n's territory is
underlain by Tertiary
sediments, which outcrop in the uplands. Several epi- sodes of
continental and marine deposition in the geosyn- cline, which
occupied most of the study area, produced interbedded shales and
sandstones, with layers of con- glomerate and limestone. Falc6n
Ranges started uplifting in the Lower Miocene, and tectonic
mo~,ements con- tinued up to the end of the Pliocene. The lowlands
are overlain by Quaternary deposits.
The Coastal Plains Province comprises the Paraguana Peninsula,
the isthmus, and the alluvial plains to the west of these. Relief
is low and even. The highest elevation corresponds to an isolated
hill (815 m) in the peninsula. The shore, subjected to the trade
winds from the ENE, is overlain by recent sand deposits, in
segments of beaches or of dunes. The rivers, which traverse the
plain s from south
to north, are intermittent and carry flash floods with suspended
sediments in the rainy season.
The Piedmont Province constitutes a belt of transi- tional
topography, with erosional and depositional land- forms, located
between the coastal plains and the moun- tain ranges. Its elevation
goes from 100 m to 400 m toward its southern border. It consists
mainly of a succession of tilted fault block ridges that stretch
parallel tO the mountain ranges and are formed by interbedded
sandstone and shale.
The Falc6n Ranges Province occupies 44% of the study area and
encompasses three parallel ridges sepa- rated by wide valleys. The
northern and medium ridges are divided into three main mountain
masses by gorges and valleys through which inner rivers flow
northward and discharge into the Venezuelan Gulf. The slopes are
steep and the relief is great, formed by knife-edged divides and
V-shaped ravines. The elevation ranges from 200 to 1500 m (800 m on
the average). To the east, some mountain remnants are found within
the Eastern Mari- time Valleys Province. On top of these remnants,
as well as on the easterly mountain mass of the northerly ridge,
karst landscapes have developed. The thick limestone masses reach a
height of up to 350 m of exposed rocks.
The Central Valleys Province encompasses the syncli-
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Land Mapping and Resources Inventory 233
Table 1. Field questionnaire, a
Date: Aerial photo no.: Cartographic sheet no.:
Nearest settlement: (Name) UFI no.: Questionnaire no.:
A) Physical environment Altitude: Soil texture: Landform:
External drainage: Stoniness class: Soil color: Water sources:
Litter coverage: %
Slope: Erosion: Microtopography: Rockiness class: Type of
fragments: Land use
type: degree:
B) Vegetation structure
Growth form Height (x) xmax xmin
Leaf % Cover Periodicity Thorniness
Texture Size Shape
C) Flora Species % Cover Spatial pattern Phenological stage
Growth form
aEach of the four parts (data on location; physical
environmental attributes; vegetation structure, flora) goes on a
separate sheet. The ranks and classes for the physical parameters
are shown in Table 2. Growth-form cover is assessed according to
Fosberg's scale (Fosberg 1967); for spedes cover the Braun-Blanquet
scale was modified to include the intermediate classes 6%-15% and
16%-25% cover. 2, = average growth-form height; xmax and xmin refer
to maximum and minimum heights of the green mass.
nal valleys between the mountain ranges. Topographic relief is
low and mostly plain or undulating, except for some low foothills
and elongated, narrow buttes. Rivers are intermittent and dried
water courses are overlain by salt deposits from the gypsiferous
shales of the neigh- bouring highlands.
The Eastern Marit ime Valleys Province comprises the basins of
the four main rivers that flow to the east and north from the
Falc6n Ranges and discharge into the Caribbean Sea. The basins are
limited by low divides formed by undulating high plains or mountain
remnants. The elevation goes from 300 m at the foothills to 0 m on
the shoreline. Slopes are mild to null, and the plains near the
coast become temporarily or permanently flooded at places.
Climate
The study area, subjected to surface trade winds from the
Caribbean Sea, presents a local climatic anomaly (Lahey 1973). At
this latitude, in such a marine location, abundant precipitation
would be expected. However, the coastal fringe has a dry climate
with limited and erratic rainfall, except for the short sections of
N-S-oriented continental shorelines.
On the mountain ranges, orographic precipitation is produced,
with rain shadows on the lee sides of the ridges. Rainfall is
heavier, as well, in those valleys opened to the ENE. The summits
are subjected to daily
cloudiness. Rainfall occurs as heavy showers within short
periods of time.
On the coastal plain, mean annual temperature is of 28~ with
only 1 ~176 variation over the year, although daily temperature
varies an average of 10~
Two climatic zones can be delimited on the basis of
precipitation to potential evapotranspiration ratio. The semiarid
zone, with a ratio from 2 to 4, comprises the Coastal Plains, the
Coastal Piedmont, and the Central Valleys. Mean annual rainfall
ranges from 170 mm to 654 mm. Climate is demarcated into two
seasons; the rainy season, by the end of the year, lasts from one
to two months. The subhumid zone encompasses the Falcon Ranges and
the Eastern Marit ime Valleys. Precipitation to evapotranspiration
ratio ranges from 1 to 2. Mean annual precipitation is from 600 mm
to 1700 ram. Rainfall is distributed in one or two rainy
seasons.
An arid zone on the coastal fringe and a humid one on the
mountain summits probably exist, but there are not enough
meteorological records to confirm these observa- tions. Climatic
pattern, as in many mountainous regions, is very variable within
short distances and largely depen- dent on topography.
Land Use
The aboriginal population that inhabited the study area
practiced agriculture under irrigation; however, it probably was
not until the arrival of Europeans that the
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234 s.D. Matteucci and others
Table 2. Ranks and classes for the physical environmental
parameters.
M
3 3 2 ,s
1 z 3 4"x~- ."5 4 3 2 1
ES EE EC
Stoniness = P No stones or very few 0 Stones covering less than
0.1% of the surface 1 Stones cover 0.1%-3% of the surface 2 Stones
cover 3%-15% of the surface 3 Stones cover 15%-90% of the surface 4
Paved with stones 5
Rockiness = A No rock outcrops 0 Outcrops cover 2%-10% of the
surface 1 Outcrops cover 10%-25% of the surface 2 Outcrops cover
25%-50% of the surface 3 Outcrops cover 50%-90% of the surface 4 A
rock outcrop 5
Erosion Wind = EE; sheet = EL;
furrow = ES; gully = EC None 0 Slight 1 Moderate 2 Severe 3
A~i tude(m) =H 0-50 1
51-100 2 101-200 3 201-400 4 401-800 5 801-1600 6
Landform = R Plain 1 Valley 2 Hill 3 Monocline 4
Type of fragments = F None 0 Up to 7.5 cm diameter 1 7.5 to 25
cm diameter 2 Larger than 25 cm diameter 3 1+2 4 3+2 5 1+2+3 6
Microtopography = M Even 1 Dunes 2 Undulating 3 Gullied 4 Mounds
5
Runof f = D Slope (%) = S Medium 0 0-2 1 Slow 1 2-6 2 Rapid 2
6-13 3 Very slow 3 13-25 4 Ponded 4 25-55 5 Very rapid 5 >55
6
stress on the environment became significant. European occupancy
in South America occurred along the coasts of what is now Falc6n
State, during the early 1500s. Though initially the purpose was to
settle in the region, and livestock was introduced, it soon became
a transient site for exploitive groups. Several attempts at
settlement failed for various reasons, including pirate assaults,
and these failures partly account for the lack of an established
agriculture. Nevertheless, the original vegetation has been cleared
perhaps several times.
Agriculture has dwindled again since about 1940 with the
development of the petroleum industry, which caused people to
abandon the farms in the search of higher economic gain. As a
consequence, large tracts of land became desertified.
At the present time, the main activity in the semiarid zone is
dryland farming, mostly goat herding at the expenses of thorn
woodland and thorn scrub, without any pastural management. This
causes heavy browsing pressures around the villages. Subsistence
shifting agri- culture is also practiced. Wood gathering for fuel
is concentrated near the villages, which are small and scattered.
All resources are used to support the family, which in general is
otherwise unemployed. Standard of living is low, and middlemen
profit from the lack of managerial techniques. The situation is
somewhat dif- ferent around the capital city of Coro, where
commercial horticultural crops are produced under irrigation. In
most of the zone, however, goats are the sole source of food and
income.
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Land Mapping and Resources Inventory 235
Figure 2. Photocoverage employed in the delimitation of the
photointerpreta- tion units.
,~ ' FALCON STATE, VENEZUELA
"Photocoverage employed in the survey
I
=m==== ~ No photocoverage available 10 0 ~0 20 30
In the subhumid lowlands, pasturelands occupy the largest areal
extent. Burning to replace forest with grass is extensively
practiced. Some management techniques are applied, but most of the
time these are not adapted to the natural conditions. On th.e sandy
shores along the east coast there are coconut plantations, and some
horticultu- ral crops are grown in scattered places near the main
roads. In the humid uplands, coffee plantations have long been
abandoned, and only subsistence agriculture is practiced.
Materials and Methods
resources of the region as a whole. It became necessary to
undertake a simultaneous study of vegetation and envi- ronment.
The main physiographic provinces and climatic zones were
delineated (Figure 1), and a preliminary descrip- tion was made.
The minimum area to be classified and plotted was set at 0.25 km 2.
A field questionnaire (Table 1) was prepared, tested along a N-S
transect, and adjusted as necessary. Classes and ranks for the
parame- ters used are shown in Table 2. Data collection took into
account the possibility of applying a parametric approach
later.
Survey Planning Stage
To determine the best way to organize the survey and to choose
the most relevant environmental factors and parameters, the
available literature was assessed. Con- currently, a field trip
through the main roads was done to recognize the general nature of
the landscape and to check some of the previously collected
information.
The study area has been greatly modified by man's activity, and
it showed various degrees of erosion and recovery. Many of the
vegetation types now present are far removed from natural
vegetation and they do not represent site potential. It was
postulated that this situa- tion would obscure the correlations
between vegetation, landform, and soils, and that vegetation units
would be smaller than landform units.
There was some information available, but it had been obtained
at different scales and with various meth- ods, and usually it
covered restricted portions of the study area. Moreover, most of
the data did not relate to the present land condition. Thus, the
existing information was inadequate to appreciate properly the
various
Photointerpretation
Vertical, panchromatic, 1/60,000 to 1/25,000 scale aerial
photographs dated from 1960 to 1977 (Figure 2) were interpreted
stereoscopically. Land segments were delineated on the basis of
homogeneous image signatures including a combination of tone,
pattern, and texture. Thus, the boundaries do not necessarily
coincide with geomorphic divisions or specific landforms; they may
reflect major changes in vegetation structure.
Deductive interpretation was employed, and a description of each
unit on the basis of landform, topog- raphy, vegetation structure,
drainage pattern, land use, and roads was prepared. This
description was later discussed and modified as necessary during
ground sur- vey. The results were compiled on transparent xerox
copies of 1/100,000 scale topographic sheets by means of an optical
pantograph.
The 556 photointerpretation units obtained were numbered, and
sample sites were selected. Since the aim of the survey was to
gather information regarding the natural resources without an a
priori decision about the
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236 s.D. Matteucci and others
P.U.N~ 144 Name: Alto de Mujica
Climatic zone: subhumid Climate: Meteorological station: Puerto
Cumarebo
Physiographic province: Coastal Piedmont Soil: orthid Soil
survey: semidetailed; COPLANARH, 1975 Water sources: no
Hydrological studies: no Drainage pattern: parallel
Vegetation structure: open semideciduous scrub Dominance type:
Bourreria cumanensis, Phyllostylon rhamnoides,
Bulnesia arborea Land use: pastoralism (goats raising without
management practises),
firewood gathering Degree of land use: slightly transformed
District: Zamora Location: 11~ , N-69~ ' W Area: 90.63 km 2 No.
of UFIs: 1 Altitude: 200 m Accessibility: easy
3C
G
20
10-
Puerto Cumarebo (13 m)
17
27.7~ 474 rnm
'"~' M k M .; '] ~ ~ 6 N 6
f lOO
8o
g L"-:
.20
Figure 3. Example of ecogram of a physiognomie unit. The
references of symbols employed in the eeogram, as well as the ranks
and classes of the parameters, are shown in Table 2.
economic activity to be developed, collection of field data was
planned for all those units that differed in one or more of the
attributes employed to describe it. Extrapola- tions to supposedly
similar units were not accomplished without confirmatory ground
observations.
Field Work
A weekly itinerary was planned every fortnight, so that field
data collected during one week could be systematized, the
photointerpretation revised, and boundaries corrected as necessary
during the next week. in the field, each unit was traversed as far
as' roads permitted, in order to verify its uniformity and the
general consistency between its description and field conditions.
Details not visible on the aerial photo were added to the
descriptions, which were modified as neces- sary. On the chosen
sites, the questionnaire was answered after examination of the site
and discussions between the team members. Ground photographs were
taken to supplement descriptions. Plant samples were taken for
later identification when they were not recog-
nized on the field. During traveling, boundaries between units
were checked and changed as necessary on the photographs and
sheets. There was more boundary checking in the east, where
photocoverage was outdated.
Interpretation of Field Data and Compilation of Maps
The field investigations confirmed what had been hypothesized
during the first stage, that is, that the photointerpretation units
were associated with the land- forms and present vegetation
structure, as determined by differences in past and present
land-use practices. These units represented a series of seral
stages, from seminatu- ral ecosystems to fully transformed systems.
In the former, basic ecosystem components and their interrela-
tions are not yet damaged, though there has been some use of
resources, mainly vegetation; they comprise land tracts in which
selective wood gathering or browsing on natural vegetation has
occurred. The transformed sys- tems comprise land segments where
the natural ecosys- tem has been ehangedby total deforestation for
cultiva- tion or for cattle raising, or for urban or industrial
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Land Mapping and Resources Inventory 237
Table 3. Example of the format employed for the description of a
land system.
Land system: Alineaci6n Septentrional Oriental (X) Area: 1190 km
2 Elevation: 20-500 m Slope: 2%-25% Geology and geomorphology:
undulating plains, underlain by Tertiary interbedded shales and
sandstone, overlain by Qua-
ternary alluvial deposits; with scattered rounded low hills
underlain by marl with thick marine limestone strata outcrop- ping
in the summit
Climate: 1000-1192 mm of annual average precipitation; one or
two rainy seasons.lasting 8 months, with peaks in July and
December; short dry spell at the beginning of the year
Drainage pattern: radial on the hills, trellis to pinnated
The system comprises two homogeneous units (HU):
HU Landform Soils Vegetation Land use
Xa Undulating plains Fine-textured saline so i ls Deciduous
seasonal forest; Cattle raising on de- dominance type: Z. forested
lands pterota, Machaerium spp., Eugenia spp.
Xb Low hills Red latheritic on the Cloud forest on the sum-
Subsistence farming slopes; deep organic on mits; dominance type:
the summits Eugenia spp.
Human population is concentrated along the main road, which
traverses the system in the E-W direction; human density is less
than 0.1 person/ha; physiographic units: 141,149, 148, 162, 163,
I64; I65, 167-P, 200, 20I-P
development. Intermediate stages comprise both units where
woodcutting or goat browsing has been more intensive, and
long-abandoned fields in different stages of secondary succession,
including areas where excessive grazing or untimely deforestation
have resulted in severe erosion and have caused a significant
productive loss. Relict natural vegetation is almost nonexistent.
Thus, differences between photointerpretation units are due to
landform and present condition of vegetation as well as tO the
direction of succession changes, which can be either toward
recovery or to desertification. The starting stage of secondary
succession and the rate and direction of change are important
factors to be considered in a tropical zone with the climatic and
topographic condi- tions prevailing in Falc6n, since changes in
habitat can be faster than vegetation recovery, thus precluding
restora- tion toward the natural vegetation type. In such a case, a
different stable community may replace the natural vegetation type
in a progressive secondary succession, or desertification may occur
if succession is regressive.'
All those photointerpretation units that were found to be
similar after field inspection and that were stationed in the same
physiographic province were combined in a physiognomic unit (PU),
and described in terms of landform, geology, climate, physical
habitat conditions, and present vegetation structure and dominance
type. The 269 physiognomie units thus obtained were mapped at
1/250,000 scale.
The potential natural vegetation (Mueller-Dombois
and Ellenberg 1974, Westhoff and Van der Maarel 1978) was used
as a criterion to obtain the homogeneous units (HU). A land segment
potential natural vegetation was judged on the basis of
stratification and complexity, diversity of growth forms,
composition of woody species, and presumed direction of succession.
Climax complexes (Whittaker 1978) were identified, and contiguous
com- munities in similar habitat types that belonged to the same
complex were combined.
The homogeneous units were gathered in systems, on the basis of
the prevailing landform and of the geologic history. The
physiognomic units, homogeneous units, and land systems areas were
measured on the map.
Results
The hierarchical classification produced 269 physiog- nomie
units, grouped in 38 homogeneous units and 15 systems. The
physiognomic units are mapped at 1/ 250,000 scale, and identified
by numbers and the name of a settlement within it. The homogeneous
units and the systems are mapped at a 1/1,000,000 scale. The latter
are named after their geographical position and identi- fied by a
roman number, and the former are identified by the system's roman
number followed by a letter.
In order that the information can meet different needs, it is
presented at various levels of integration and gener- alization.
Thematic maps and reports are presented for
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238 s.D. Matteucci and others
Table 4. Summary of the main characteristics of Falc6n State
land systems, a
System and area Geology Major soils
Landform Major Altitude drainage vegetation and pattern type
slope
Present land use
I Quaternary al- 2260 km 2 luvial deposits
II 550 km 2
II I 1130 km 2
IV 1360 km z
V 1440 km 2
VI 1300 km 2
VII 4230 km 2
VII I 1070 km 2
IX 590 km 2
Interbedded sandstone and shale, Mio- cene to Plio- cene
Same as I
Interbedded sandstone and shale Mio- cene to Plio- cene
Eocene to Mio- cenesand- stones and
conglomerate
Eocene to Plio- cene interbed- ded sandstone and shale
Heterogeneous: same as V, sandstone and conglomerate, marine
lime- stone
Same as VII
Tertiary gyp- sipherous shales
Floodplain, par- Medium tex- From thorn 0-160 m allel stream-
tured, locally woodland to 0%-4% lines clayey and deciduous
saline. Cam- seasonal for- borthids, Tor- est in a N-S
riorthents, gradient Pateargids, Haplargids
Dissected coas- Shallow, stony, Thorn scrub 0-160 m tal plain;
ra- saline. Or- and thorn 0%-6% dial and trel- thents, Or- woodland
lis drainage thids, Argids
Same as I, sand Medium dunes to tlae textured coast
Orthents,
Orthids, Camborthids, Salorthids, Haplargids, Psamments
Tilted fault- Shallow lithic block ridges, soils, rock some
plains & outcrops. Or- hills; trellis thents, Or- drainage
thids, Argids,
Camborthids Mountains bor- Shallow, lithie
dered by low on eroded hills, trellis slopes; or- and pinnate
ganic on the drainage summits; red-
dish brown elsewhere. Orthents, Or- thids, Argids, Tropepts, Us-
talfs
Same as V Same as V
Same as V, small undu- lating upland plains
Mountains and hills; complex slopes
Mountains, bor- dered by low foothills; ra- dial and trel- lis
drainage
Thorn wood- land
Thorn wood- land
Deciduous sea- sonal forest; cloud forest
Deciduous sea- sonal forest
Same as V; Same as V; de- limestone out- forested for crops,
same as pasture seed- V and Ren- ing dolls, Ustolls
Same as VII Same as V
Shallow lithic soils with rock outcrops; red clayey. Orthents,
Tropepts, Us- talfs, Ustults, Orthids, Us- terts
Pasture, rem- nants of de- ciduous sea- sonal forest
0-100 m 0%-4%
160-500 m 0%-25%
200-800 m 6%-13%
200-800 m 15%-55%
400-1200 m 2%-40%
300-1500 m 15%-55%
160-800 m 6%-25%
Goat herding on natural vege- tation to the N; cattle on seeded
pas- ture to the S
Unused mar- ginal lands; goat herding
Horticultural crops under irrigation
Goat herding on natural vege- tation, subsis- tencefarming
Cattle raising, subsistence farming
Cattle raising to the W; goat herding on rangelands
Cattle raising, subsistence farming; sugarcane
Subsistence ~rming
Cattle raising
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Land Mapping and Resources Inventory 239
Table 4. Continued.
System Landform and drainage area Geology pattern Major
soils
Major Altitude vegetation and
type slope Present land use
X Eocene to Plio- Undulating Fine textured, 1190 km 2 cene
interbed- plains with saline,
ded shale and scattered low patches of sandstone; hills; radial
reddish soils. marl and pinnate Orthents,
drainage Tropepts, Us- talfs, Ustults, Camborthids, Chromus-
tens, Torrior- thents
XI Quaternary al- Gently undulat- Same as X and 1310 km 2 luvial
deposits ing plains, lo- Ustifluvents,
in tectonic ba- calized sea- Argids, Or- sin sonal and thids,
Usterts,
permanent Ustolls flooding; den- dritic to par- allel
drainage
XII Same as XI Flat lowlands, Same as X 3240 km z seasonal
and
permanent flooding, bor- dered by low hills; parallel or
dendritic
x I i I Eocene to Mio- Undulating Shallow, lithic 1470 km z cene
interbed- plains, low or fine tex-
ded sandstone foothills and tured overlain and shale elongated
by salt de-
buttes; Den- posits in dried dritic and water courses. pinnate
Orthents, Or- drainage thids, Argids
XIV Quaternary de- Intermountain Medium to fine 680 km 2 posits
valleys; textured. Or-
featherlike thents, Or - drainage thids, Argids
XV Upper Creta- Low, flat plains Very heteroge- 2530 km z ceous
to Pa- with isolated nous, medium
leocene ig- hills; den- to fine tex- neous rocks, dritic very
tured. Tor- Tertiary de- sparse to dif- riorthents, posits fuse
drainage Torripsam-
ments, Cam- borthids, Aq- uents, Zor- rerts, Orthids,
Orthents
Pasture, patches 20-500 m Cattle raising, of deciduous 2%-25%
subsistance seasonal for- farming est
Same as X, patches of de- ciduous sea- sonal forest with upper
layer of scle- rophyllus trees
Same as XI
0-160 Cattle raising 0%-1%
80-300 m Cattle raising, 0.1%- 16% permanent
crops (coco- nut)
Thorn scrub 80-200 m Goat herding on and thorn 2%-6% natural
vege- woodland ration
Pasture, decid- 375-600 m Cattle raising, uous seasonal 6%- 13%
goat herding forest, gallery on natural re- forest getation
Thorn scrub, 0-100 m Goat herding on thorn wood- (830 m) natural
vege- land, dry ev- 0%-1% tation, subsis- ergreen bush- tence farm-
land ing, annual
crops
aThe names of the systems are given in the legend of Figure
4.
major environmental factors: climate, geology and geo-
morphology, vegetation, soils, and hydrology.
Each physiognomic unit is described on a standard- ized format
or ecogram, as shown in Figure 3. The polygonal figure shows the
physical nature of the habitat,
and was constructed in the fashion of the Lutz phyto- graphs
(Shimwell 1971). Each axis represents a physical parameter. The
parameters were ranked in such a way that the higher the value, the
more limiting was the condition. The lowest value for each
parameter lies on
-
240 s.o. Matteucci and others
",, t - "
71000 , 70~30 '
70000 9
Villa
LAND SYSTEMS IN FALCON STATE
69~ ' I 69000 , 68~ I
t 11o30,
11000 9
KM
1'0 0 10 20 30
,-~ Boundary between systems ,"" Boundary between homogeneous
units
Figure 4. Land systems and homogeneous units (HU) in Falc6n
State. Land systems are indicated with roman numbers and HUs with
letters:/, Planicie Aluvial Occidental; II, Sureo de Urumaco; III,
Planicie Aluvial Mitare-Seeo; IV, Piedemonte Costero; V, Serran[a
Bariro-Pedregal; 111, Alineaci6n Central Occidental; VII,
Alineaci6n Meridional; VIII, Serranla de San Luis; IX, Alineaci6n
Central Oriental; X, Alineaei6n Septentrional Oriental; XI, Cuenea
del Hueque; XII, Valles Mar~timos; XIII, Sistema de Depresiones;
)(IV, Valles Intermontanos; XV, Peninsula de Paraguan~.
the perimeter, and the values increase centripetally. Thus, the
polygon shape and size give a visual indication of the physical
condition of the land. The climatic diagram follows Gaussen's
design (Walter and others 1975); it corresponds to the station in
the unit or to the nearest station in a similar topographic
position. Vegeta- tion structure is shown in a layer diagram.
In a final report, a general description of each system is
given, as shown in the example of Table 3. Ground photographs and
stereograms are added to illustrate major features. The
distribution of the systems and homogeneous units is presented in
the map (Figure 4). A summary of the main characteristics of the 15
land systems is given in Table 4.
Discussion
Land surveys endeavour to divide a region into com- prehensive
units. If the task is carried out on the basis of sound ecological
principles, the classification approaches a natural system with
standardized attributes. Hence, the
results can be used for various purposes. Uniform land tracts
can be assessed and classified in terms of their suitability for
one or more forms of land use or for nature conservation, taking
into account those attributes rele- vant for the purpose at hand.
The classification can also serve as a framework for the
extrapolation of the results of site research, or for the choice of
sites or resources on the basis of a global appreciation.
Even though parametric methods for land classifica- tion that
permit extensive statistical treatment and com- puterized analysis
of data are now available, the land- scape approach allows quick
identification of uniform segments at various levels of
generalization, an d provides a framework for objective data
gathering. The use of a "poor man's approach," in which
conventional data collection and analysis, as required for a
parametric method, are replaced as far as possible by a maximum of
less formal observations, is of great practical value as a first
approximation to a regional land survey of large regions. In some
situations, it is the only applicable approach. Limitations imposed
on the results can be
-
Land Mapping and Resources Inventory 241
overcome by further study of selected land tracts, once those
with less potential for the desired purpose are eliminated. Gaps of
knowledge with reference to biologi- cal and physical attributes,
identified in the course of the first approximation, can be filled,
as detailed studies are undertaken in the chosen land units. At
this stage, the assumed degree of uniformity in landform, geology,
soil, and vegetation within a certain land category should be
subjected to rigorous correlation tests, in order to verify the
basic assumptions. Thus, the system not only allows the collection
of additional data, but it also permits the improvement of the
model through an iterative process.
There is a discussion over terminology, as regards the
definition of different categories of land-units. This is due to
the fact that the names proposed by the Australian researchers are
used with various connotations by dif- ferent authors. In order to
avoid adding to the confusion, we preferred to give other names to
our land-units. However, the physiognomic unit is equivalent to the
land facet as defined by Perrin and Mitchell (cited in Cooke 1977)
as "one or more land elements grouped for practi- cal purposes;
part of a landscape which is reasonably homogeneous and fairly
distinct from surrounding ter- rain." From the practical point of
view, these units would respond uniformly to a certain management
practice; they may constitute the basis for the delimitation and
identification of agroecosystems. The homogeneous units represent
an intermediate category between CSIRO's land-unit and land system.
They were introduced to account for situations in which, within a
land system, there exist units evolving towards recovery and units
suffering a desertification process; thus, though their landform
and soils do not differ greatly at the present moment, they differ
in their potential natural vegetation. Similar responses to
management practices cannot be expected. Land systems, described in
terms of major landform and geologic history, are equivalent to
CSI- RO's complex land systems (Christian and Stewart 1968).
In this survey, scant regard was given to the human factor.
Following FAO's recommendation (FAO 1976) and in view of the
extension and complexity of the area, the social analysis was left
for a future stage in the survey of selected zones. The results of
the survey allow for the choice of promising sites and resources on
the basis of the physical and biotic characteristics only. The
final deci- sion requires consideration of the cultural and
economic components of the system.
Acknowledgments
The research reported herein was supported by the Research and
Development Convention (National
Research Council, Venezuelan Science Research Insti- tute,
University Institute of Technology of Coro, Central University of
Venezuela, National University Francisco de Miranda). The
preparation of the manuscript was financed by the National Research
Council of Venezue- la.
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