Spatial - Ecological Assessment of Land-use / Land-cover: Agriculturally-disturbed “Tropical Moist Forest (Cool Dry Transition)” in the Caparo River Valley, Republic of Trinidad & Tobago

Authors: Karl Ramjohn, Floyd B. Lucas, Carol L. Ramjohn & Winston Johnson, Tropical Environment Research & Management Center, Trinidad & Tobago. January 2006

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ECOSYSTEM
CLASSIFICATION & FUNCTIONAL DYNAMICS

Beard (1946) classified the study area as being predominantly Seasonal Evergreen Forest (mixed Crappo-Guatecare). Beard’s study (which remains as the only comprehensive ground-based island-wide assessment of flora) focussed on classifications based on dominants within the community, mainly from an economic timber and Forestry management perspective. Those classifications represent conditions ~60 years ago, and several of the species assemblages described by Beard (1946) are no longer recognizable, having undergone significant alterations, fragmentation and conversion into secondary forest and other land-uses (Ramjohn et al.2001, Joseph 1999, Nelson 1999).

A more recent study by Nelson (2004), which attempted classification of indigenous forests based on a landscape-ecology and ecosystem-management perspective, delineated Trinidad into two major terrestrial eco-regions – Dry Forest and Moist Forest. According to that study, the project site (confluence of the Caparo and Mamoral Rivers) is located approximately on the boundary between the two eco-regions; thus it may be regarded as being within a transition zone between two significant moisture regimes. Based on maps prepared by Nelson (2004), the middle and upper reaches
of the Caparo Basin would be in the wetter region supporting “Tropical Moist Forest”, with the lower catchment in the drier region classified as “Tropical Moist Forest, Cool Dry
Transition”.

The long history of agricultural activity in the Caparo Valley has resulted in significant alterations to the native vegetation and forests. In general, higher-quality closed-canopy forest remains only as a few patches in this area (Nelson 2004). These forested remnants largely persist on the higher slopes of the occasional spurs and ridges, such as the area immediately north of the project site. The higher-integrity forest remnants persist as patches embedded in a wider (macro-habitat) matrix of cultivated areas, grassland/lastro and secondary forest. As a result of the traditional land-use patterns, much of the vegetation resources in the immediate vicinity of the confluence are of agricultural origin. Therefore, while natural and semi-natural vegetation exists in the surrounding area, the agronomic aspects of the biological environment will have a more dominant role in defining the site’s ecological character.

From an ecosystem perspective, agricultural production systems may be regarded as restructured and simplified natural environments, as they rely on plant-based biomass productivity through photosynthesis, nutrient recycling via microbial activity, etc. However, their functioning requires subsidised ecological processes, and their habitat structure and complexity (as well as spatial arrangement of biota) are intentionally simplified and controlled, to focus on the productivity of a small number of targeted elements. Agricultural ecosystems are land-use units comprising soil, crop, tree, weed, livestock, pathogen and insect sub-systems that continuously interact to transform solar energy, water, nutrients, labour and other (e.g., agro-chemical) inputs into biomass yields as food, feed, fuel,
fibre and pharmaceuticals.

Furthermore, even in areas of Trinidad where secondary forests have regenerated via natural succession (subsequent to agricultural abandonment), the historical land-use patterns are often critical factors in determining the ecological integrity of the “replacement” ecosystem. Depending on the type of previous cropping systems, physical and biological remnants of the agricultural activities may strongly influence (either beneficially or adversely) their natural sucessiontrajectories, as well as ecosystem structure and function, and related trends in their biodiversity and other natural resources.

Archival land-use maps indicate that in this
part of Trinidad, agriculture was dominated by Cocoa (Theobroma
cacao) and Coffee (Coffea arabica) production to the north of the Caparo Valley Brasso
Road, with Sugar Cane (Saccharum sp.) cultivation dominating to the south of the road. Thus, the project
site was in an effective boundary zone between the two major historical
export-cropping systems of economic importance. At present, there is little Cocoa production remaining in the
immediate area, although Sugar Cane cultivation still takes place within parts
of the study site. Much of the agricultural land formerly under Cocoa was subsequently cultivated with
Citrus (Citrus sp.), especially a 1200-acre site downstream in the Palmiste/Todds’ Road area. In the wider study area, land
still under Cocoa/Coffee production is located higher in the catchment of the Caparo River, such as Benji
Trace (approaching Flanagin Town).

VEGETATION CHARACTERISTICS & LAND-COVER QUALITY

The project site for the surveys was
centred in the area surrounding the confluence of the Caparo and Mamoral Rivers. As
such, the primary focus for site characterization was on the area around Carr
Caparo Trace, Carr Mamoral Trace, Lynch Trace (Mamoral Road),
and the stretch of the Caparo
Valley Brasso Road
adjacent to the proposed development. However, to assist in fitting the
proposal into the existing land-use and development patterns of its landscape
unit (in the context of cumulative impacts), an overview of ecological
conditions was obtained by paying brief visits to other areas along the Caparo
Valley Brasso Road (both north and south of the site), including Palmiste,
Todds’ Road, Chickland/Caparo Road, Santa Phillipa Road, Benji Trace and
Flanagin Town.

The vegetation surveys at the site (and
surrounding areas) revealed four broad classes that can be used to describe the
land-use/land-cover from a spatial/ecological perspective. These are summarized
in Table-03:

IMAGE-01: EXAMPLES OF LAND-COVER / TERRESTRIAL VEGETATION AT CAPARO / MAMORAL

IMAGE-02: EXAMPLES OF AGRICULTURAL VEGETATION AT CAPARO / MAMORAL

RIVER
BANK VEGETATION

As
noted on Table-03, three main classes of vegetation were found growing in the
riparian zone along the Caparo and Mamoral Rivers within the study
area:

(i)
Semi-closed
riparian community

(ii)
Semi-open
riparian community

(iii)
Open /
disturbed riparian community

(i) Semi-closed
riparian community

Typical examples of
this class along the river bank are indicated on Image 01-01 and a
representative example of the vegetation was surveyed at Site V-03 and along
the boundary of Site V-02. The classifications as “semi-closed” and “semi-open”
do not represent absolute distinctions (in that no physical measurements of
canopy-closure were done). However, they were based on visual inspection and
other on-site observations of the ecosystem processes/functions such as
micro-climate/micro-habitat conditions, in terms of the degree of ‘shade’
provided to the river channel by the riparian communities, as well as other
ambient indicators of moister conditions, such as communities of mosses on the
riverbanks (above the high-water mark) and on the branches/trunks, the presence
of Myceteae, and the degree (and likely dynamics) of
plant-derived organic matter (e.g., leaf litter) on the forest floor.

In terms of their ecology, these patches
may be seen as representing higher-quality habitats along the river. However,
this represents the habitat conditions in terms of their form and functional
dynamics, as opposed to their botanical representativeness
(i.e., presence or absense of native trees and
related plant assemblages). They persist mainly in areas of the riverbank on
Carr Mamoral Trace that are too steep or narrow to be
cultivated and have regenerated to more ‘natural’ conditions.

The main trees identified in these areas
included Jamoon (Syzygium
cumini), Hog Plum (Spondias
mombin), Angelin (Andira inermis), L’Epinet (Fagara marticensis), Water Immortelle (Erythrina
fusca), Conore (Lonchocarpus domingensis),
Milkwood (Sapium glandulosum) and Manjak (Cordia collococca).
These can generally be regarded as widely distributed native trees often found
in riparian or other water-associated habitats. In these areas, their structural
significance is in the provision of conditions bearing higher resemblence to natural canopy. The presence of Roseau (Bactris major), Balisier
(Heliconia bihai)
and Souhari (Calathea
lutea), as well as stands of larger graminoid-type vegetation such as Bamboo (Bambusa vulgaris)
and Wild Cane (Gynerium sagittatum)
and vines like Dutchman’s Pipe (Aristolochia
grandiflora), would assist in sealing off the
habitat edge (with respect to direct sunlight) thereby enhancing the
micro-climate conditions experienced here. Moisture-holding plants like Balisier also provide niche micro-habitat conditions that
support specialized aquatic faunal communities.

Unlike other areas (such as Carr Caparo Trace), the river channel does not appear to have
been dredged at these locations, which is also likely to have a role in the
maintenance of the observed conditions. The river banks are typically steep
with a drop of ~2.5 to 5 m to the river. Within the river channel itself, there
was a high degree of heterogeneity in the substrate (in terms of depth and
topography), with rocky areas and significant amounts of semi-submerged
branches and trunks. Beyond the (average) high-water mark in the channels,
thick communities of encrusting mosses were observed to have colonized the heavy-clay
substrate on the sloping banks. Micro-habitats of mosses and similar
communities were also observed on the trunks and branches of the standing trees
in the more-shaded areas.

Overall, the vegetation patches with
micro-climate supporting semi-closed riparian communities may be viewed as
minor pockets of higher productivity, biological resource value, and
carbon/energy storage (organic matter pools) in the wider landscape of
agricultural and other disturbed habitat surrounding the Caparo/Mamoral
River system.

(ii)
Semi-open riparian community

Typical examples of this class along the
river bank are indicated on Image 01-03 and a representative example of the
vegetation was surveyed at Site V-07. Superficially, the “semi-open” areas appear
to support similar conditions to the “semi-closed” riparian habitat described
above. However, there is considerably less of a canopy development with the
‘shaded’ conditions in the channel mostly resulting from thick stands of Bamboo
(Bambusa vulgaris)
and occasional (lower density of) trees. As such, the habitat is more open to
direct solar radiation for several hours each day.

The trees recorded for these areas
included Mountain Immortelle (Erythrina poeppigiana), Water Immortelle (Erythrina
fusca), Angelin (Andira inermis),
Hog Plum (Spondias mombin),
Black Fiddlewood (Vitex divarcata),
Milkwood (Sapium glandulosum), Manjak (Cordia collococca)
and Jereton (Schefflera
morotoni), together with pioneer species like
Wild Tobacco (Acnistus arborescens)
and Bois Canot (Cecropia
peltata). The moister conditions have led to the
riverbanks being widely colonized by Wild Dasheen (Colocosia
esculenta); however, there was little evidence of
Balisier or other Heliconia
species.

(iii) Open
/ disturbed riparian community

The riparian vegetation in these areas
is represented by plant communities (mainly grasses and cultivated species
other than tree crops) indicative of disturbance. This class is very common in Trinidad in areas
traditionally associated with agriculture. Typical examples of this class are
indicated on Image-01-02 & Image-02-01, and a representative example of the
vegetation was surveyed at Site V-11, in addition to which basic observations
on vegetation were made at aquatic survey Site MD-3 (which was associated with
an open/disturbed habitat of this nature). In these areas, the river banks have
been entirely cleared of trees and other native riparian vegetation, usually to
facilitate agriculture. In some parts of the study area, the open/disturbed
river banks were not cultivated at the time of the survey; however, in others
there were crops on the banks (or in the immediate vicinity) especially by the
bridges on Carr Caparo Trace (Site V-11) and Mamoral Road (Site MD-3).

The healthier riparian ecosystems
described (i.e., semi-closed riparian class) were characterized by
sparsely-vegetated channel slopes (primarily mosses), as a result of the moist
conditions with limited sunlight penetration on the ground-level. In contrast,
the banks of the open/disturbed areas were bounded by thicker vegetation such
as grasses and vines, with the immediate area of the banks dominated by Wild
Dasheen (Colocosia esculenta),
and Water Grass (Commelina erecta and Commelina
diffusia). These are supported by the perpetually
moist organic soils with unimpeded exposure to sunlight; Dasheen in particular
thrive in high-nutrient, water-saturated soils (Gouveia
et al. 1994).

Some of the river banks with
open/disturbed vegetation were associated with Sugar Cane production. However,
in some areas small plots of vegetable cultivation were also seen in the
riparian zone. These were mainly herbaceous crops like Cucumber (Cucumis sativus),
Pak Choi (Brassica
chinensis) and Lettuce (Lactuca
sativa), as well as Ochro
(Abelmoschus esculentus)
and Pigeon Peas (Cajanus cajan).

The trees present in the areas
classifiable as open/disturbed habitat had a greater tendency to be isolated
and thus not associated with the development of a canopy. These were mainly
trees commonly recorded for the study area, such as Jamoon
(Syzygium cumini),
Water Immortelle (Erythrina fusca), Milkwood (Sapium glandulosum),
and Pink Poui (Tabebuia
rosea). Close to Site V-11 a few Teak (Tectona grandis)
and Caribbean Pine (Pinus Caribea) trees were observed in close association with
a small cluster of Roseau Palms (Bactris
major). Teak and Pine are two of the major (introduced) species planted by
the Forestry Division for the commercial timber industry. However, at this
site, they were not part of a forest plantation and had probably been planted
by an individual smallholder (incidental to the cropping
system).

RIVER
VALLEY VEGETATION

As noted on Table-03, three main classes
of vegetation were found growing in the alluvial flat land in the low-lying
valley areas along the Caparo and Mamoral Rivers within the study
area:

(i)
Active
agricultural land (occupied by crops)

(ii)
Inactive
agricultural land (grassland / scattered trees)

(iii)
Village /
residential (fruit trees, ornamentals, etc.)

(i)
Active agricultural land

While almost all of the flat land in the
area surrounding the Caparo/Mamoral River system may
be classified as agricultural, not all such areas were under active cultivation
at the time of the vegetation surveys. Typical examples of land classifiable as
being under “active” agriculture are indicated on Image-02-02 &
Image-02-03, and representative examples of this vegetation would have been
surveyed in most of the areas within Sites V-02 to V-05 (along Carr Mamoral Trace).

The health and ecosystem function of
agricultural areas (both within and between sites) will depend on all
components of its ecological character: physical (climate/soils), biological –
vegetation (crops, weeds, other plants) and fauna (pests, beneficial insects,
livestock, and wildlife species associated with semi-open areas), human inputs
(labour, energy, water, chemicals) and overall interactions. In a spatial,
ecological (and commercial) sense, the most significant cultivated crops within
the project site (Caparo/Mamoral confluence) are
Cassava (Manihot esculenta) and Sugar Cane (Saccharum officinarum). These two crops
cover most of the larger agricultural plots under active cultivation. Smaller
amounts of other short-term food crops are planted commercially in this area,
such as Pigeon Peas (Cajanus cajan), Ochro
(Abelmoschus esculentus),
Sorrel (Hibiscus sabdariffa), Pawpaw (Carica papaya) and Banana (Musa sp.), as well as an area on Carr Mamoral Trace in which “Portugal” Oranges (Citrus sp.)
are cultivated. The wider area does not have a pipe-borne water supply (relying
on water-trucks) and thus it is likely that the river is used both as a source
and a sink for agricultural water.

In the
immediate project area, Sugar Cane cultivation is focussed mainly between the Carr Mamoral
Road and the river bank (Sites V-02 to V-05); however, unlike larger
estates, it is not continuous within this area and is interspersed with
Cassava, grassland and other vegetation. Sugar Cane is a very
large graminoid (grass-type) vegetation (growing up
to 3 m tall) and on flat land areas they are typically planted on banks to
prevent inundation during the wet season. Harvesting of the crop is generally
preceded by the systematic burning of the fields. At times of harvesting the
soil in these areas is left relatively exposed, which would have ecological
implications associated with increased erosion potential and run-off into the
river; however, the crop season is generally within the first few months of the
dry season. The larger monocultural areas of Sugar
Cane in Central
Trinidad
have been described as representing effective “deserts” for many species of
wildlife (personal comments Graham White). However, based on observations
for the present survey, this effect may be less drastic at the project site, as
a result of the relatively small areas under Sugar Cane cultivation (and the
lack of spatial continuity between such areas).

As a result of favourable soil
characteristics and other factors, Cassava is the most commonly cultivated root
crop in the Caparo Basin (Grant et al.
1996). This is a broadleaf shrub that grows to heights of 2 m; however, the
targeted component is the root tubers (i.e., its below-ground biomass). Cassava
cropping requires considerable soil disturbance and modification to organic
matter and nutrient regimes (Kellman & Tackaberry 1997). It is usually planted on banks (which are
kept clear of weeds), generally at the start of the annual wet season and harvested
about 8-9 months later (Seesahai 1996); however, the
varying size of the plants seen in the study area during January 2006 indicates
that there is not strict adherence to this technique. A study by Grant et al.
(1996) on small Cassava farms at Longdenville (lower
down in the Caparo Basin) described the
production system as “chemically-intensive” (fertilizers, pesticides, etc.).
Relatively large monocultures of Cassava were observed along the Carr Mamoral Trace, especially in the areas surrounding sites
V-02 and V-03 (closer to the river, on the edge of the larger Sugar Cane
field).

(ii)
Inactive agricultural land

Typical examples of land classifiable as
being “inactive agricultural” are indicated on Image-01-04, and representative
examples of this vegetation would be found throughout Sites V-02 to V-05,
especially in the area surrounding Site V-04. While inactive agricultural areas
dominated by grassland are often described as ‘abandoned’ or ‘lastro’, in this area it is considered likely that the land
is used for agriculture at other times (and left in its current grassland state
as part of a fallow system).

Overall, grasslands at inactive
agricultural areas are often regarded as “fire-climax” ecosystems (especially
where they bound Sugar Cane cultivation), and tend to exhibit landscape
similarity to savannas, as they are characterized by a few dominant grass
types, with scattered individual (or occasional clumps of) trees. However, they
are structurally and functionally simpler and considerably less diverse or
unique than the natural savanna ecosystems that have
developed in other parts of Trinidad (Armstrong et al.
2004, Comeau & Clubbe
1998). The graminoid-dominated inactive agricultural
lands in Trinidad may also be regarded as representing
areas of “arrested succession” in the natural environment (personal comments
Stanley A. Temple), since the exotic (non-native) grass species typically
colonizing these ecosystems tend to inhibit the rate at which natural forest regeration takes place.

Inactive agriculture land along Carr Mamoral Trace is dominated by coarse perennial grasses,
mainly Bull Grass (Paspalum fasciculatum) with some Elephant Grass (Pennisetum purpureum)
in wetter areas. The grasses are interspersed with vines such as Kudzu (Pueraria phaseoloides)
and other small herbaceous flowering plants on the roadside, such as Railway Daisey (Bidens alba). Several variably-sized patches of Bamboo (Bambusa vulgaris)
were also observed in the grassland areas on inactive agricultural land along
Carr Mamoral Trace. While this is a non-native
species in Trinidad (originating in the Asian tropics), Bamboo has become
widespread throughout the island, especially as an early-stage sucession component of the vegetation in agricultural or
other frequently disturbed areas (Teixeira & Oatham 2001), often with dispersal and colonization by
‘natural’ means.

At
the inactive agricultural site surveyed along Carr Mamoral
Trace, one species of significance among the scattered trees was the Royal Palm
(Roystonea oleracea).
This very tall straight-growing palm that attains a height of 30 – 50 m, is tolerant of a wide range of environmental conditions
and is thus fairly widely distributed. Black Fiddlewood (Vitex
divaricata) is another fairly large native tree
observed in this area.

(iii) Village
/ residential

This class is used to describe the
vegetation typically found in the village areas adjacent to the project site
the along the Caparo Valley Brasso
Valley Road (e.g., Site V-10); it is also used to account for the differences
in vegetation found at the small clusters of houses and isolated residences in
the agricultural land along Carr Caparo Trace and
Carr Mamoral Trace (e.g., Sites V-02, V-03, V-04 and
V-11).

The gardens of the houses usually have
ornamental plants such as small palms, flowering shrubs and shade trees, many
of which are non-native species. Also, some small-scale food cropping usually
takes place in the immediate vicinity the houses, primarily for household
consumption (as opposed to the larger commercial production of Cassava and
Sugar Cane in this area). However, the main difference observed around houses
is the greater presence of trees. The trees surrounding the housing areas at
the project site are predominantly fruit trees– Coconut (Cocos
nucifera), Mango (Mangifera
indica), and Breadfruit (Artocarpus
communis) with lesser amounts of Pommerac (Syzygium malaccense), Pewa (Bactris gasipaes)
and Plum (Spondias purpurea)
trees, as well as occasional Cashew (Anacardium
occidentale) and Betel Nut (Areca catechu).

Roadside vegetation in these areas
typically consists of widely dispersed grasses, other herbaceous plants and
shrubs such as Fowl-foot Grass (Eleusine indica), Savanna Grass (Axonopus compressus),
Railway Daisy (Bidens alba),
Sensitive Plant (Mimosa pudica), Broom Weed (Sida acuta),
Stinging Nettle (Laportia aestuans), Wild Hops (Flemingia
strobilifera), St. John’s Bush (Justicia secunda)
and Candle Bush (Piper tuberculatum).

2.3.3.3
Intermediate Upland Vegetation

The immediate north of the study site is
characterized by a comparatively steeply-sloping ridge, which rises to an
elevation of ~100 m. As noted on Table 2-10, three main classes of vegetation
were observed in this area:

(i)
Forest patches in higher
elevations (remnant indigenous, secondary)

(ii)
Hillside / valley cropping
systems

(iii)
Village /
residential (fruit trees, ornamentals, etc.)

(i)
Forest

On higher ridges of hill to immediate
north of site (not directly accessed for the current survey) the vegetation is
dominated by tree species typical of seasonal evergreen tropical forest. The
composition of the plant community will be a combination of the species
recorded in the lowlands (which tend to be forest species that are easily
dispersed) and other tree species more indicative of the natural plant
community.

Angelin (Andira
inermis), Hog Plum (Spondias
mombin), Black Fiddlewood (Vitex
divarcata), Milkwood (Sapium glandulosum),
Manjak (Cordia collococca), Olivier (Terminalia
amazonia) and Jereton (Schefflera morotoni)
are some of the main species likely to be encountered in these areas, based on
their occurrence in survey points on the edges of the forested ridge (e.g.,
Sites V-12 and V-13). The main difference is that on the higher slopes, a
higher-quality canopy structure (and therefore ecological integity)
is to be expected. Species such as Acurel (Trichilia oblanceolata)
and Wild Chataigne (Pachira
insignis), though not encountered in the survey,
may be found on steeper (less accessible) slopes. Notwithstanding this, it is
less likely that the dominants of the seasonal evergreen formation (Crappo-Guatecare association) as described by Beard (1946)
will remain on these slopes, particularly Crappo (Carapa guianensis)
and Guatecare (Eschweilera
subglandulosa) as they are much sought after and
extracted for their timber.

(ii)
Hillside / valley cropping
systems

Typical examples of higher land under
agricultural use (hillside / valley cropping) are indicated on Image-02-04, and
representative examples of this vegetation were surveyed at Sites V-06 and
V-12. While the higher land and ridges of the hill formation to the north of the
project site remains primarily under forest or forest-derived vegetation cover,
some agriculture was observed to be taking place. For example, while most
cultivation along Carr Mamoral Trace was within the
flat alluvial valley (already described), some cultivation was observed on the
lower slopes of the ridge to the extreme north of this area. Such activity
focussed on Cassava (Manihot esculenta) cultivation and
appeared to be having only a minor ‘footprint’ impact, in relation to
encroachment on the bulk of the surrounding upland forest vegetation and
structure.

In relation to this higher elevation
feature, the main area of hillside/valley cropping was on a lower part of the
ridge (~30 m), in the eastern part of the project site. In that area, the
south-facing slope is bounded by Carr Mamoral Trace
and was not under active cultivation at the time of the survey, dominated by
grassland with tall isolated trees (mainly on the top of the ridge). The
north-facing slope is bounded by Lynch Trace (Site V-06 just north of Mamoral Cemetery) and this slope was
extensively cultivated by a monoculture of Pigeon Peas (Cajanus cajan). Lynch Trace also
accesses the forest on the adjacent higher parts of the hill, and in the
valleys of this area cultivation of almost exclusively Pigeon Peas with lesser
amounts of Ochro (Abelmoschus
esculentus) was observed. However, this area can
be distinguished from the flatland agriculture surrounding the Caparo/Mamoral confluence by the higher degree of
forest-derived vegetation surrounding the plots.

Generally, the entire hillsides are not
under crops, the cultivated areas are patches of plots, which exist in close
association with the upland forest and forest-derived ecosystems. The roadside
along Lynch Trace was dominated by forest-edge vegetation such as Bois Canot (Cecropia peltata), Bois Flot (Ochroma pyramidale),
Wild Tobacco (Acnistus arborescens),
Black Sage (Cordia cussaravica)
and extensive stands of Bamboo (Bambusa vulgaris). However, larger trees were observed in the
surroundings including Mountain Immortelle (Erythrina
poeppigiana), Water Immortelle (Erythrina fusca), Roble (Platymiscium trinitatis), and Hog Plum (Spondias
mombin) as well as palms such as Carat (Sabal mauritiiformis)
and Royal Palm (Roystonea oleracea).

Other areas with hillside/valley
cropping were surveyed on the northern side of the ridge (Site V-13), accessed
via Carr Caparo Trace. The main crops observed were
Cassava and Sugar Cane. However, an even higher diversity of native trees was
observed in this area (several of which were not recorded for the lowland parts
of the study area) including Cuchape (Coccoloba latifolia),
Olivier (Terminalia amazonia),
Cocorite (Attalea
maripa), Kiskidee (Vismia cayennensis),
Bois d’Orme (Guazuma
ulmifolia), L’Epinet (Fagara marticensis)
and Juniper (Genipa americana),
as well as Teak (Tectona grandis) and Mahogany (Swietenia
macrophylla).

(iii) Village
/ residential

This area is an effectively
linear/clustered settlement along parts of the ridge road (accessed from Carr Caparo Trace), with the houses surrounded by (and
interspersed with) secondary forest and agriculture. Representative examples of
this vegetation were surveyed at Site V-12. In addition to the typical
ornamental plants, fruit trees and small-scale cropping at the houses (as
described for the flat land areas on Carr Mamoral
Trace), the plant community in this area contains tree species that are
remnants of the wider forest areas, such as on the higher elevations on the
adjacent ridge (immediately south of the houses).

Species such as Hog Plum (Spondias mombin), Manjak (Cordia collococca), Bois d’Orme (Guazuma ulmifolia),
Jereton (Schefflera
morototoni) and Black Poui
(Tabebuia chrysantha)
were recorded on the southern side of the road. On the opposite side of the
road there were a few Teak (Tectona grandis), Castilloa Rubber (Castilla elastica),
Mahogany (Swietenia macrophylla)
and Mango (Mangifera indica)
which are all introduced species and most likely planted in the area in the
past. Roadside vegetation consisted of Bull Grass (Paspalum
fasciculatum), Wild Hops (Flemingia
strobilifera) and the vine Kudzu (Pueraria phaseoloides).

SPATIAL
– ECOLOGICAL DATA REPRESENTATION

References:

Armstrong, R.,
Oatham, M. & Ramlal, B. 2004. “Plant Community Changes on the Erin
Savannah”. In Ramjohn, C.L. (ed). Proceedings of “The Nature of the Islands”: A Conference
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Tobago Field Naturalists’ Club; 52 pp.

Beard, J.S.
1946. The Natural Vegetation of Trinidad. Clarendon Press, Oxford; 146 pp.

Comeau, P. & Clubbe, C.C.
1998. Savanna Expansion in Trinidad West Indies. Living World 1997-98 – Journal of the Trinidad and
Tobago Field Naturalists’ Club; pp. 23-27

Gouveia, G., Ahmad, N. &
Griffith, S. 1994. The Effects of Urea-N on Yield, Productivity, and
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62-67

Grant, L., Mainville, D., St.
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