STRUCTURE AND DIVERSITY OF A RIPARIAN FOREST AT KAIETEUR NATIONAL PARK, GUYANA

2008·36.3 MB·English

by  Carol L Kelloff

AND A
STRUCTURE OF RIPARIAN FOREST
DIVERSITY
GUYANA
AT KAIETEUR NATIONAL
PARK,
L
Carol Kelloff
MRC166
Department of
Botany,
USA.
DC20013-7012,
Washington,
email: [email protected]
ABSTRACT
onalPark, encompassing n .onions of th e Potaro River, Guyana, contains a mo:
rESSHE
T,ZZ££Z
Kwakwani and
(Guyana) Barro Cole
f
2^3=
'B
:3
—
xedby
E.jakat
:r;m
::z
::i
RESUMEN
Eperuafalc
pteridophylla y
var.
ntifolia
INTRODUCTION
km
Kaieteur National Park the only national park in Guyana, located approximately 230 southwest
(Fig. is
1).
W)
(5° 10' 42" N; 59° 29' 44" of Georgetown, the nation's capital. The park is situated on an upland region
Guyana known Pakaraima Mountains. This plateau an eastern extension
of as the Potaro Plateau of the is
known
mountains
Venezuelan Roraima sandstone formation forms the table-top
of the largely that flat
km
as tepuis. The Potaro River flowing over this plateau has cut a 20 gorge in the easternmost portion of
the Roraima formation. The river eventually plunges 226 meters via a single drop into the gorge. Kaieteur
main
and
Falls one of the most spectacular cataracts in the world is the geological feature of the national
is
522 Journal of the Botanical Research Institute of Texas 2(1)
km
2
park. The park was established in 1929 and encompassed 44 to protect the area around the falls, the
km
2
Potaro gorge, and the surrounding Potaro Plateau. Today the park has been expanded to 627 to protect
and
around and expanse savannas
greater representation of the vegetation the a larger of the forests
a falls
of the plateau. In 1998, the park was incorporated into the National Protected Areas System (NPAS) that
NPAS
With Guyana
currently being developed part of Guyana's ecotourism business. this Project,
as
is
management
urgently needs information on the biodiversity of the area before any conservation or policy
can be implemented. Botanical exploration of the mid- to lower portions of the drainage has been limited
the area around the and along the Potaro gorge; such exploration has resulted in a checklist of the
to falls
&
vascular plants of the area (Kelloff Funk 1998), but there have been virtually no ecological studies in an
attempt quantify species
to diversity.
some
In general, tropical forests have been characterized as having a high diversity of trees, with inven-
cm
tories recording over 300 species with a diameter at breast height (DBH) > 10 per hectare (Gentry 1988;
&
Hubbell Foster 1986; Valencia 1994). Several hypotheses offer explanations regarding the mainte-
et
al.
nance high Huston's 1994) "dynamic equilibrium hypothesis" suggests that diversity in
of (1979,
diversity.
populations reached by low competitive displacements or by periodic reductions in species (Huston
of
rate
is
number
slow-growing
the population has high or high frequency of disturbances, species will
1979). a
If
disappear and be replaced by the faster-growing pioneer species over time thus reducing diversity. In order
minimum
overcome must have some growth recover from population reductions. In
to this species rate to
can
other words, an increase in growth rates during periods of high frequencies of population reduction
Another an response environmental
actually increase diversity (Huston 1979). hypothesis ecological to
is
conditions such as low and high light conditions. By changing the availability of resources, disturbances
may move and
such as canopy gaps influence succession. Those species efficient in recruitment quickly in,
&
The under low
the becomes covered with pioneer species (Bazzaz Picket 1979). ability to survive light
site
conditions and the ability to achieve high growth under high light conditions is the most significant differ-
&
can
ence between species diversity (Bazzaz Picket 1979; Hubbell 1995). the survival of the fittest that
It's
which
Guyana, Dicymbe Spruce ex
utilize the disturbance, increasing the diversity of species. In Benth., is
When
known
locally as clump wallaba, produces coppices (suckers) on the healthy parent tree. the parent
these young can take advantage of the mature root system of the parent, as well as the light
trees die, trees
and thus can out-compete other species in the area (Henkel 2003; Steege 1993).
gap, ter et
al.
Not show high alpha however. Productivity and disturbance vary in
tropical forests a tree diversity,
all
&
Lowman
mixed
and
the tropics (Richards 1952; Connell 1989), this evident in the forests of central
is
&
Guyana where there a tendency for some species to dominate the vegetation (Davis Richards 1934;
is
&
Guyana
Fanshawe 1952; Johnston Gillman 1995; ter Steege 1993). Several examples of this type of forest in
&
are the wallaba (Eperua Aubl.), mora (Mora Benth.), or clump wallaba (Dicymbe) forests (Davis Richards
1934; Fanshawe 1954; Henkel 2003; Steege 2000b). These forests have a few species that represent a
ter
high percentage of the stems and/or basal area.
and
The Guyana wide mangrove, moist dry
tropical forest of contains a array of forest types, e.g., ever-
swamp
green, montane, seasonal, swamp, and Greenheart In and mangrove forests, edaphic factors
forests.
mixed
such flooding and explain these types (Fanshawe 1952). However, in the forests
as soil clearly forest
of Guyana, the relationship between soil, hydrology, and forest types is not clear (ter Steege et al. 1993).
&
has been based on and physiognomy (Ducke
Generally, classification of forest types largely climate, soil,
Black 1954; Prance 1987), which reference species compositions or have generalized tropical floras at the
&
genus or family (Forero Gentry 1988; Maguire 1970; Steege 2000a). Recent studies used
level ter et
al.
how
plots to examine patterns of plant diversity, species richness (Gentry 1988) or habitat diversity
e.g.,
&
Tuomisto Ruokolainen
contributes to species diversity Steege 1993; Sabatier et 1997; 1997). Plot
(ter al.
on
produce and can provide long-term information growth, mortality,
studies data the species re-
at level
Sampling riparian trees of the plateau using a grid system of collecting allows us to describe the
(1)
Guyana
Kaieteur National Park,
Keiloff,
m
Kaieteur located along the Potaro River Guyana, has a single drop of 226 into the splash basin below.
Fig. 1 Falls, in
.
Journal of the Botanical Research Institute of Texas 2(1)
524
framework by which
abundance and provide the forest structure of
distribution of the trees, a
relative (2)
known
can be compared other study help in the missing tree taxa in the checklist,
Kaieteur to sites, (3) fill
by which and composition can be measured.
and provide standard structure
a forest
(4)
on
This paper presents the results of the two, one-hectare (ha) inventories carried out the Potaro
comparison
were used
within Kaieteur National Park. Tree data from two other plot studies as a of
Plateau
Guyana
the tree diversity at Kaieteur. Data from two one ha plots were borrowed from a lowland forest in
town Kwakwani Guiana Shield community) and two one ha portions of a 50 ha plot at Barro
near the of
(a
from Guiana
Colorado Panama (non-Guiana Shield community). In general, plot data the Shield
Island,
One
ha allow us quantify
and particularly the Potaro Plateau are scarce (ter Steege et 2000a). plots for to
al.
among and add knowledge
the relationship between tree species as well as tree species to the of the tree
was document
The the species diversity
Potaro Plateau in Guyana. ultimate goal of this project to
diversity of
and compare
and composition of the Wallaba (Eperud) -mixed forests of the Potaro Plateau to the tree
tree
species diversity of Kaieteur National Park to those of other plots.
The study site.—Kaieteur National Park a mosaic of habitats consisting of exposed sandstone, grass savanna,
is
(USDA The
and The average temperature the year 26.5°C 1974). average
scrub, riparian forests. air for is
mm
(Fanshawe
Pakaraima escarpment approximately 3750 per year
rainfall for the northeast face of the is
The
Two ha were established in the Wallaba (Eperua) -mixed forest of the Potaro Plateau. study
plots
1953).
1
both
was conducted between 1995 and 1998 with selected based on the surrounding vegetation. In
sites
human were removed
some was found
ha previous disturbance several large trees for
of
plots, level (e.g.
1
Korume
Creek
The headwaters the
located the of
the building of the guesthouse). first plot (Fig. 2a) is at
and
o The inundated includes portion
10'42"N, 59°29'44"W). lower portion of the plot seasonally a
first is
(5
Along western
which grew few patches Thurnia sphaerocephala (Rudge) Hook.f. the side
of the creek in a of
was
up towards Muri-Muri savanna. The second plot 2b)
of the plot, the land gradually rises the ravine (Fig.
(5°HT6"N,
Korume and
between Creek Potaro River gorge
established in the upland forest of the plateau the
downward
59°28'52 W). The rocky with a slope towards the northeastern part of the trail.
,I terrain slight
is
There no evidence of seasonal flooding as in the plot.
first
is
The from two were not analyzed, but was generally observed that they consisted of a
these
soils sites
it
Pakaraima
course white sand of quartzite with very peat. These shallow white sand areas of the Plateau
little
Guyana.
(Fanshawe 1954) are associated with the peneplain of the interior of
Kwakwani
town
The lowland Guyana used comparison are located near the of at
plots in the area of for
km New
Amsterdam
up from
the Aroaima (bauxite) mining on the Berbice River, 238 the Canje River
site
Man
Comiskey
58°W). Data these were kindly provided by James (Smithsonian Institution
(5°30'N, for plots
mm
The low
The 2400 per land
in the BioSphere Program). average rainfall recorded for this area is year. is
swampy The were within the area designated as
lying with areas near the river. sites for the plots selected
"south mine," proposed area future bauxite mining. In this area, the shallow layer of topsoil (averaging
a for
Both
60 meters volcanic rock. plots
meters in depth) covers nine meters of bauxite that overlays of
1.5 ca.
mixed (Comiskey
and non-flooded
were irregular in shape, the vegetation classified as tropical forest et
is
1994). was noted that the soil was composed of a mixture of sand and clay with high porosity and high
al. It
The were sampled (Comiskey
not 1993).
drainage. soils et al.
The second set of plots were part of a 50 ha study site at Barro Colorado Island (BCI) located near the
o
Panama Canal the Smithsonian Tropical Research Institution's station (9°9T7"N, 79 50'53"W). This for-
at
Leguminosae
by Bombacaceae and (Condit
growth dominated
est classified as a rich, old tropical forest
is
The on summit with a variance of 28 meters in elevation.
1996). terrain the island's is relatively level
et
al.
mm
mean
2500 with annual tem-
The about per year (Condit 1996) a
average rainfall for this area et al.
is
The BCI with an organic matter content (Yavitt 2000).
perature of 27°C. soil at is a clay-rich tropical soil
&
by
Hec21 Hec37) were and kindly provided
Data from two of the 50 ha plots (designated as selected
1
Richard Condit
for this study.
Guyana
Kaieteur National Park,
Kelloff,
526 Journal of the Botanical Research Institute of Texas
2(1)
Established on the central plateau of BCI, the 50 ha permanent plot has a 70 year history of the flora
&
and fauna and over 1500 papers written on various topics (Hubbell Foster 1992). For more
scientific
information on Barro Colorado Island, selected readings are: Hubbell and Foster 1992 and Hubbell et
al.
1995.
—
Census methods. The method adapted inventorying the woody vegetation of Kaieteur followed Dallmeier
for
made
(1992). The terrain at both sites was uneven, and corrections were to adjust for slope (Durr et al. 1988).
20m
The two ha Kaieteur were subdivided 25 contiguous 20 x quadrats, and stems with
plots into a
1 at all
DBH
minimum cm
of 10 were measured. Spatial location of the trees within each quadrat was recorded for
mapping purposes. Field vouchers were obtained, where possible, for each species encountered. Information
was wood, and
recorded to aid in identifications of the vouchers, features of the bark, sap (Polak
sterile
e.g.,
Romeo
1992; Rosayro 1953). William, tree spotter and guide, assisted in the identifications of trees in the
names
field. Local or vernacular for trees (Fanshawe 1947, 1953, 1954) helped to identify morphologically
similar trees. Most vouchers were sterile and thus required extensive time in the herbarium for identification.
when
Trees were identified to the species level possible, but were otherwise assigned to morphospecies.
Taxonomic nomenclature Guianas: Guyana, Surinam,
followed the "Checklist of the Plants of the
Guyana
French Guiana" (Boggan 1997). Voucher specimens were deposited in the National Herbarium,
et
al.
DC
Guyana (BRG) and Herbarium, Washington,
University of the U.S. National (US).
at
how
and dominance were
Density, frequency, calculated describe individual species are spatially
to
how
and community
distributed within the plot these distributions contribute the (Barbour 1987).
to et
al.
Stem
basal area and density of each tree were calculated using a = 0.7854 x (DBH) where a = basal
(a)
2,
m &
2
area of each tree in (Anderson Ingram 1989). This measurement useful in estimating canopy cover
is
We
(DBH)
because assumes trunk diameter breast height
of trees to take at into account. also calcu-
it
sum
lated species basal area (BA), defined as the of stem basal areas of a given species. Density
all (a) is
number
defined as the of trees per hectare, and relative density the percentage of one species in relation
is
number
frequency
to the total plant diversity. Relative expressed as a percentage of the of quadrats that
is
A
Dominance
contain a given species. an important ecological measurement. species that contributes the
is
Dominance
most community dominant
cover or basal area to the considered the species. calculated
is is
community
importance
Finally, the relative contribution that a species provides to the called value
is its
The importance value index can be by
(Balslev et 1987). (IVI) calculated the addition of the relative
al.
density, frequency, and dominance for each species and for all trees at each site. High IVI values indicate
when
that a species has a high basal area, frequency, and density at a site or one or two of these parameters
&
much sum
The
are higher than other species da Silva 1993). of relative parameters places species
(Felfili
&
community
and comparisons between
in a hierarchical order in the useful different (Curtis
for sites
is
&
Mcintosh 1951; da Silva 1993). The IVI values can range from to 300, with 300 representing a
Felfili
pure stand one
of species (Balslev 1987).
et
al.
—
Statistical analyses. Spatial and temporal variations in tropical tree communities can complicate the process
and raw from can be
of describing forest structure (Dutilleul 1993; Hall et 1998), species data plots too
al.
and cumbersome any meaningful Ordination can reduce abundance
large to yield intrinsic patterns. species
(Gauch
data into a space with fewer dimensions that can sample configurations in ecological space
reflect
&
community some
Whittaker such can
1981). In ecology, ordinations describe of the strongest patterns
& &
McCune
(McCune
in species composition Mefford 1999; Grace 2002). Ecologists have applied metric
which components
ordination, includes principal analysis (PCA), to analyze vegetation data (Proctor 1967;
&
assumes
Debinski Brussard 1994; Tuomisto 2003). This type of ordination a linear relationship
et
al.
methods more
able obscurity in data interpretations (Goodall 1953). Non-metric ordination are considered
powerful for analyzing vegetation data because this method assumes a non-linear relationship between the
Guyana 527
Kaieteur National Park,
Kelloff,
and ranked between measured
variables the use of distances tends linearize the relationship the distances
to
&
(McCune
and
in environmental space species space Mefford 1999).
PC-Ord
were summarized and imported
Species data per plot into data matrices (taxon vs. quadrat) into
&
(McCune
Grace multivariant program. Because the data represent quantitative scores
2002), a statistical
per taxon, the original values were log transformed using = + where the value of one added
log(x.. is
b.. 1),
Log any dominant and
to each species score to define zero values in the data. transformation reduces effects
& &
common McCune
Kempton
normalizes the importance of or rare species (Digby 1987; Grace
relative
among (NMS)
To non-metric multidimensional
2002). visualize multivariate patterns the quadrats, scaling
NMS
PC-Ord
was conducted using S0rensen (Bray-Curtis) distances for each plot and on each plot pair. in
based on Mather's (1976) program and the algorithm of Kruskal (1964).
is
mode PC-Ord was mode random
For each dataset in this study, the "autopilot" in used. This provided a
starting configuration for each run. The program calculates each solution by running 40 runs with the real
maximum
number 400 The
and 50 runs with randomized with
data the data, a of iterations for six axes.
program where Monte and where
selected the best solution at each dimensionality p < 0.05 for the Carlo test
parameter was number. thumb" were used
that value of the the smallest Clarke's (1993) "rules of to
"stress"
community
interpret the final stress. Clarke found that most ecological data will have values with a final
between and
10
stress 20.
NMS
provides an optimal ordination technique to analyze patterns in tree species composition for each
of the studies. The final result in each analysis was an ordination in two-dimensional space. The two axes
show between abundance and
the relationship species the axis score.
DBH
cm
Guyana.— number
Kaieteur National Park, There were 1724 of stems >10 Kaieteur in the
total at
m
KF1
two study plots. These stems covered a total basal area of 66.34 2/ha. Plot at Kaieteur contained 757
Cowan
(swamp
stems per hectare, with most taxa represented by a single stem. Dicymbe pharangophila R.S.
wallaba, Leguminosae-Caesal.) produced coppice shoots from the base of the trunk that resulted in 65 stems
being measured and tagged from of 28 This habit of producing multiple stems from the base
a total trees.
was noted by Whitton and Henkel Dicymbe corymbosa Spruce ex Bentham, another
also (1962) (2003) of
"swamp on The was
wallaba" found the Potaro Plateau. largest diameter tree recorded for the Ocotea sp.
site
DBH DBH cm
with 89 cm. Other with > 60 were DC.)
(Lauraceae), a of species a Pouteria cuspidata (A.
cf.
Bentham
Baehni (Sapotaceae) and Swartziaschomburgkii (Leguminosae-Fab.). Sixty-four percent of the stems
cm
cm
were under 20 in diameter, and only one percent of the trees reached over 60 DBH. The two species
that had the highest Important Value Index (IVI) were Chamaecrista adiantifolia (Spruce ex Bentham) H.S.
& &
Irwin Barneby pteridophylla (Sandwith) H.S. Irwin Barneby (Caesal.; IVI=20.052) and Eperuafalcata
var.
These two were found throughout and accounted 13.4%
Aublet, (Caesal.; IVI=15.427). species the plot for
Ducke
Dicymbe Ormosia Dicymbe
of the stems. pharangophila (IVI=14.679), coutinnoi (Fab.; IVI=10.109), sp.
(IVI=10.027) and Pouteria cuspidata (IVI=10.442) ranked next in importance. These species accounted for
32%
stems recorded KF1.
of
total for
The understory species were not recorded, but was noted that two species of Marantaceae (Ishnosiphon
it
One
and Monotagma spicatum (Aublet) Macbride) dominated the lower wet areas of the species
sp. plot.
J.F.
&
Canargo dominated
of Bromeliaceae (Ananas parguazensis L.A. L.B. Smith) the dryer soils of the plot.
Hooker was abundant and grew
Thurnia spherocephala (Ridge) (Thurniaceae) quite in the flowing waters
f.
of the creek.
The second plot (KF2) at Kaieteur had more stems (967) than the first plot. Dicymbe pharangophila was
cm
DBH)
and
nearly absent from this plot. Chamaecrista adiantifolia var. pteridophylla (95 Swartzia schom-
cm
DBH)
burgkii Bentham (Fab.; 92 were the largest trees recorded for the followed by Elizabetha sp.
site,
cm DBH
cm cm
DBH)
66 and DBH). Stems 20 accounted
(Caesal; Pouteria cuspitata (64 or less for 69.5%,
cm
whereas only 1.0% of the stems exceeded 60 in diameter. Several species ranked high in IVI: Eperua
Journal of the Botanical Research Institute of Texas 2(1)
528
and
Ocotea spp. (IVI=18.253),
(IVI=20.048), Chamaecrista adiantijolia var. pteridophylla (19.486),
falcata
When
commune Ormosia
Catostemma Sandw. (Bombaceae; IVI =15.082),
Swartzia schomburgkii (IVI=17.404).
40.3%
and Eperua (IVI=15.702) are added, these species account for of the total
(IVI=12.328), spp.
coutinnoi
stems recorded KF2. The understory species were not surveyed, but was noted that Ishnosiphon
plot
for it
Lem.
and Monotagma spicatum were somewhat evenly distributed in the plot. Vriesea splendens (Brongn.)
sp.
was
from but
(Bromeliaceae) was seen along with the spiny bromeliad (Ananas parguazensis) the first plot
A
Baker
not abundant. broad-leaf aroid grew on tree trunks, and a Rapateaceae (Stegolepis ferruginea
as f.)
dominated understory quadrat
the
at 14.
number stems
In both Kaieteur, the Leguminosae had the highest of individuals per site (815
plots
at
Bombacaceae
most which were from subfamily Caesalpiniodeae In plot
47.3% the (607).
or of the plots) of 1
had
64 Bombaceae,
most abundant quadrats with stems. in plot
ranked second family across
as the all 2,
77 stems but ranked third Lauraceae (136 stems).
after
cm DBH
Kwakwani two
Kwakwani, Guyana.—There were 995 stems > 10 in the plots, these
a total of at
m
2 hundred and seven stems were recorded from plot (AR1)
with basal area of 52.13 /ha. Five first
a total
cm
DBH. The on
Kwakwani. Only had second stem measuring over 10 largest tree the site
four trees a
at
&
cm
DBH.
was Trymatococcus amazonicus Poepp. Endl. (Moraceae) at 91 Eschweilera pedicellata (Rich.) S.A.
23% and had an
Mori (Lechythidaceae) represented of the total stems (115 stems) in this plot IVI of 33.425.
by
The taxon with next highest IVI was Aspidosperma excelsum Benth. (Apocynaceae) followed
the (6.751)
(Annonaceae;
(Annonaceae; Unonopsis R.E.
rujescens Fr.
Bocageopsis multiflora (Mart.) R.E. Fr. 6.733), (Baill.)
and
Swartzia schomburgkii (Fab.; 5.116), Prunus sp. (Rosaceae; 3.857), finally Cordia sagotti I.M. Johnst.
6.190),
21%
(Boraginaceae; These taxa represented 163 stems or of the stems counted in the site. Sixty three
3.795).
cm DBH 2% cm DBH:
were under 20 and only were over 60 Eschweilera pedicellata
percent of the stems
ex
(Lecythidaceae; 88.2 cm), Aspidosperma excelsum (Apocynaceae; 85.9 cm), Alteia niopoides (Spruce Benth.)
and
Burkart (Leguminosae-Mimos.; 83.5 cm), Inga pezizijera Benth. (Mimos.; 76 cm), Bocageopsis multiflora
(Annonaceae; 72.8 cm).
(Mart.) R.E.
Fr.
Kwakwani Aspidosperma
The second (AR2) had only 491 of single recordable stems. excel-
trees
plot
at
sum was cm) and had the highest IVI value of 63.671 (138 stems,
the largest tree (91 Eschweilera pedicellata
28% Two were Mora (Kleinhoonte) Sandw. (Caesal.;
other taxa significant gonggrijpii
of the stems).
total
Mora
IVI=36.486) and Aspidosperma excelsum (IVI=15.600). Inga acrocephala Steud. (Mimos.), gonggrijpiU
Klotzsch ex Miq. (Sapota-
DC. Chrysophyllum
Eschweilera sparciflorum
Swartzia polyphylla (Fab.), pedicellata,
cm
3% DBH.
and Aspidosperma excelsum represented the of the total stems over 60 Fifty-six percent
ceae),
were under 20 cm.
stems
of the total
was most abundant family Kwakwani, with 254 stems documented for the two
Lecythidaceae the
at
were
Leguminosae was second most abundant with 184 stems (107 of these Caesalpinioids in site
the
plots.
AR1
and
Boraginaceae
Next rank were Annonaceae with 55 stems over quadrats in (34 stems).
in the all
2).
AR2
had more and
and Apocynaceae stems in
In 2 these families represented only 19 2 stems. (26)
site
had
abundance stems.
ranked third in across the plot. All other families less
Panama.— two ha from the Barro Colorado Island (BCI) 50
Barro Colorado In the plots selected
Island,
1
cm
ha > 10 was 57.153 rnVha. Information provided for this study includes
the basal area of trees
plot, total
No and were
only data the main stem on each plot. data were available for multiple stems thus these
for
The had
had
excluded from this study. The first plot (designated as Hec21 at BCI) 418 trees. tree that the
cm
on was Hura (Euphorbiaceae; 102.1 DBH). Seventy-five percent of
diameter the crepitans L.
largest site
DBH
the trees had < 20 cm DBH. Two percent of trees had a > 60 cm: Brosimum alicastrum Sw. (Moraceae;
Don
cm) and
Tabebuia
88.5 cm); Chrysophyllum (Sapotaceae; 88. Jacaranda copaia (Aubl.) D. (82
cainito L.
5)
and
82 cm); Luehea seemannii
guayacan Hemsl. (Bignoniaceae; 82 cm); Prioria (Caesal.;
(Seem.) copaifera,
&
The dominant Hec21 were Faramea A.
Triana Planch. (Tiliaceae: 76.8 cm). species for occidentalis (L.)
&
CDC.
= (Triana Planch.) (Meliaceae; IVI = 23.870),
Rich. (Rubiaceae; IVI 18.644), tuberculata
Trichilia
529
Guyana
Kaieteur National Park,
Kelloff,
= and Hemsl. (Rubiaceae; IVI = 10.344). These taxa
IVI blackiana
Prioria copaifera, (Caesal.; 17.581), Alseis
accounted for 139 trees or one-third of the entire tree census.
Hec37 447 62.6% which were < 20
The second BCI) contained recordable of
plot (designated as at trees,
cm was with diameter 209.5
DBH. Ceibapentandra Gaertn. (Bombacaceae) the largest tree in the plot a of
(L.)
cm DBH
cm
DBH. Other species over 60 were Ficus costaricana (Liebm.) Miq. (Moraceae; 138 cm), Tachigali
&
Hum
Aspidosperma
(Euphorbiaceae; 99.4 cm),
Standi. L.O. Williams (Caesal.; 109.1 cm), crepitans
versicolor
&
Woodson
(Apocynaceae; 89.0 cm), Dendropanax arboreus Decne. Planch. (Araliaceae; 83.0
cruenta (L.)
and Liebm. (Cecropiaceae; 66.0 cm);
cm), Brosimum alicastrum Sw. (Moraceae; 75.3 cm), Cecropia insignis
Woodson (Bombacaceae; 69.8
Guapira standleyana (Nyctaginaceae; 75.3 cm); Quararibea asterolepis Pittier
The dominant on were Faramea
cm); and Guatteria dumetorum R.E. (Annonaceae; 63.5 cm). species the site
Fr.
two accounted almost
= and these
occidentalis (IVI 23.340) Trichilia tuberculata (IVI=27.239); together, for
31% Other with high IVI values were two Bombacaceae: Quararibea
the countable stems. species
of total
and
(IVI=14.721) Ceiba pentandra (IVI=12.455).
asterolepis
From two examined Barro Colorado Rubiaceae ranked the highest for individual
the plots at Island,
The Leguminosae
stems Meliaceae, with 122 ranked second in the "tree per family" category.
(217). trees,
contained only 67 stems, 47 of which were Caesalpinioids.
A
summary most abundant from study can be found in
comparative of the tree species the six sites
Table
1.
(NMS) was used reduce each
analyses.—Non-metric multidimensional the datasets
scaling to at
Statistical
with
the three study In each plot there were several species that exhibited a strong relationship
of
sites.
The
on
the ordination scores. These species were displayed the ordination as a joint plot. radiating lines
and influencing the separation of the
of the joint plot reflect the direction strength of that species that is
KF1 had The was 15.68692
quadrats in the plot. Plot at Kaieteur 103 species in the analyses. final stress
was The two
the 3-D solution with 99 iterations. The Monte Carlo test for this solution p < 0.0196. first
for
56.8% accounted 74.1%. Three patterns are seen in
axes accounted of the variance; the three for
for first
on Dicymbe Chamaecrista
grouping quadrats based species assemblages 3A). spp., adiantifolia
the of (Fig.
and
(Bombacaceae) form one group, Chamaecrista
Alnso.
pteridophylla, Pachira (Pulle) Fern.
var.
flaviflora
&
Barneby and Vahl form second group;
Irwin Pterocarpus (Fab.) a
apoucouita (Aubl.) H.S. (Caesal.) rohrii
composed
some whereas group
these two groups have a stronger influence in of the quadrats a third of
Aubl Ducke (Mimos.) and species in Meliaceae have a
Hevea (Euphorbiaceae), Inga
guianensis
gracilifolia
on
stronger influence others.
KF2 The 3-D
Kaieteur plot had the fewest species (71) in the dataset. best result for the dataset is the
NMS
The
ordination from with a stress value of 13.30984 with 162 iterations (Monte Carlo p < 0.0196).
82.5%
variance for the two axes accounted for 66.4% of the variance; if the third axis is included, of
first
by two
assemblages influenced
the variance accounted Quadrats in the plot are separated into species
is for.
Bombacaceae macrocarpa
groups: the Licania alba (Bernoulli) Cuatrec. (Chrysobalanaceae), spp., Clathrotropis
Ducke Ocotea and Macrolobium suaveolens Spruce ex Benth. (Caesal.) group;
Eschweilara
(Fab.), spp., spp.,
van Werff
and DC. (Melastomataceae), Sextonia rubra (Mez) der (Lauraceae),
the Henrettea
ramiflora (Sw.)
and Catostemma commune Sandw. (Bombacaceae) in the other (Fig. 3B).
Inga sp.3,
NMS
was 3-D
from runs
Combining the data from the two plots Kaieteur, the best result multiple a
at
solution (stress = 18.09208, p < 0.0195) with a variance for the first two axes accounting for 54.6% or 75.0%
including the The two axes were chosen for the ordination to best represent the data (Fig. 3C).
third.
first
Axis and showed separation between the locations of the plots. Axis
represents the area of collection
1 little
KF1 and KF2.
2 represents a clear separation between the species and their assemblages at plots Species that
and
contributed the discrimination in KF1 were Dicymbe pharangophila, Eperua rubiginosa Miq. (Caesal.),
to
KF2
were Eperua
Catostemmajragrans Benth. (Bombacaceae). Species contributing to discrimination in spp.,
was no composition between
and Ocotea There overlap in species
Sextonia rubra, Henriettea spp.
ramiflora,
two
quadrats of these plots.
Journal of the Botanical Research Institute of Texas 2(1)
iL
III
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