Plant Community Structure, Fire Disturbance, and Recovery in ...

Contributions to the Study of Biological Diversity Vol. 3
only a few of the most sensitive species were
eliminated. The dominance of most of the
disturbance-adapted species will likely be
temporary, while others, such as Typha, may
persist for long periods.
Northwest District
The family rankings illustrate moderate
consistency at higher taxonomic levels between
the countrywide flora and those of the Northwest
District and the Waini Peninsula. Of families
listed only in the Waini top ranking, most have
a high component of wetland-adapted species,
such as Malvaceae, Combretaceae, Moraceae,
Rhizophoraceae, Arecaceae. Also represented
for the Waini were disturbance adapted families
such as Amaranthaceae, and Pteridaceae, and a
family dominated by vines, the Convolvulaceae.
The number of species records contributed
to the list for the Northwest District by recent
collection efforts illustrates the incomplete state
of investigations into the region’s flora. Limited
financial and professional resources require that
collecting efforts be aimed at the localities most
promising for shedding light on biodiversity and
conservation questions. Associated with this,
there is a great need to make additional historical
collection data available for such analyses.
Preparing additional museum specimen data is
labor intensive but is cost effective in
comparison to performing new fieldwork, and
will provide increasingly useful data to answer
biodiversity questions and guide future research.
As biodiversity research efforts progress in
Guyana, compilation of species distributions
will likely become increasingly focused on the
finer levels of detail, such as by political
divisions within countries. The tendency to use
political divisions should be tempered by the
growing ability to analyze a growing body of
georeferenced specimen data using climatic,
geological, elevational, and distance data with
geographic information systems, allowing
questions to be more readily framed and
answered in terms of environmental and
ecological units.
Delta Amacuro
It is still not certain how much overlap
should be expected for plant species of the Waini
Peninsula and in Delta Amacuro. Collecting
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expeditions in almost any under-collected
locality of the Guiana Shield region tend to yield
new distributional records. Few botanical
collections in Delta Amacuro have taken place
along the coast near to Guyana; the closest
known coastal collection locality is Punta
Barima, more than 70 kilometers northwest
along the Atlantic coast from the Waini
Peninsula. Although both areas have similar
coastal and estuarine environments, it was found
that over 30% of the plants listed for the
Northwest District are not known for Delta
Amacuro. This difference can be compared to
the same statistic for nearby areas. Twenty-one
percent of Surinam’s known vascular plant
species are not recorded for French Guiana, and
18% are not recorded for Guyana. However, in
comparison, for the diverse, mountainous
Venezuelan segment of the Guiana Shield, 42%
of the plant species listed for Bolívar state are
currently not listed for Amazonas state
(Steyermark et al. 1995 - 2005). Latitudinal and
edaphic differences between the Northwest and
Delta Amacuro, particularly the extensive
deltaic environment found only in Delta
Amacuro, in addition to the high overall level
of endemicity in the Guiana Shield region,
suggest that a sizable portion of the plant species
listed in only one region will continue to be
unnknown in the other. Still, only the assembly
and analysis of additional collections can clarify
the relationship between the two areas.
These comparisons highlight the
incomplete state of botanical knowledge of these
regions, and should serve as incentives and goals
for plant specimen collecting efforts. They will
also hopefully serve as encouragement for
further analyses of the spatial patterns of the
turnover of species in the tropics.
Regional and Global Affinities
The differences between affinities of the
Waini Peninsula flora and those of the species
of the interior Kaieteur location illustrated some
interesting points. The coastal Waini
communities included many species with broad
ranges, with the four top categories being
Neotropical and Pantropical distributions and
the sixth ranked category being Cosmopolitan,
which included a variety of herbs. The fifthranked
category, Northern South America, and