El. Webb et R. Peralta, TREE COMMUNITY DIVERSITY OF LOWLAND SWAMP FOREST IN NORTHEAST COSTA-RICA, AND CHANGES ASSOCIATED WITH CONTROLLED SELECTIVE LOGGING, Biodiversity and conservation, 7(5), 1998, pp. 565-583
In the Atlantic lowlands of Northeast Costa Rica, logging occurs in tr
acts of poorly drained wet forest ('swamp forest'), yet little is know
n about factors affecting swamp forest diversity or the potential for
biodiversity retention during harvest. This paper quantitatively descr
ibes the species composition and diversity of the swamp forest habitat
, and reports the immediate impact of controlled, selective logging on
tree community diversity. Pentaclethra macroloba (Leguminosae), Carap
a nicaraguensis (Meliaceae) and Pterocarpus officinalis (Leguminosae)
accounted for >70% of the primary swamp forest basal area. Nevertheles
s, 225 species from 53 families with individuals greater than or equal
to 10 cm dbh were encountered in 16.4 ha; most species had very low a
bundances. Gamma diversity is a component of overall swamp forest dive
rsity, Extraction of 49.2 m(3) ha(-1) (5.5 trees ha(-1)) of timber fro
m a 4 ha plot reduced species richness by 14, supporting assertions th
at random mortality during logging can affect the distribution of rare
species. However, tree community diversity as measured by rarefaction
was not greatly affected by selective logging. Total post-logging ste
m recruitment over a 3-year period was greater in logged plots than in
undisturbed plots; the recruitment of the ruderal species Ochroma lag
opus (Bombacaceae) was the most clearly affected by logging. Any local
ized dominance by this species will be limited in space and time in a
carefully managed forest. The results suggest that controlled selectiv
e logging can be consistent with biodiversity conservation, and comple
ment protected areas in Northeast Costa Rica.