SPECIES-DIVERSITY IN VERTICAL, HORIZONTAL, AND TEMPORAL DIMENSIONS OFA FRUIT-FEEDING BUTTERFLY COMMUNITY IN AN ECUADORIAN RAIN-FOREST

To test the hypotheses that fruit-feeding nymphalid butterflies are ra ndomly distributed in space and time, a community of fruit-feeding nym phalid butterflies was sampled at monthly intervals for one year by tr apping 6690 individuals of 130 species in the canopy and understory of four forest habitats: primary, higraded, secondary, and edge. The ove rall species abundance distribution was well described by a lognormal distribution. Total species diversity (gamma-diversity) was partitione d into additive components within and among community subdivisions (al pha-diversity and beta-diversity) in vertical, horizontal and temporal dimensions. Although community subdivisions showed high similarity (1 -beta-diversity/gamma-diversity), significant beta-diversity existed i n each dimension. Individual abundance and observed species richness w as lower in the canopy than in the understory. However, rarefaction an alysis and species accumulation curves revealed that canopy had higher species richness than understory. Observed species richness was rough ly equal in all habitats, but individual abundance was much greater in edge, largely due to a single, specialist species. Rarefaction analys is and species accumulation curves showed that edge had significantly lower species richness than all other habitats. Samples from a single habitat, height and time contained only a small fraction of the total community species richness. This study demonstrates the feasibility, a nd necessity, of large-scale, long-term sampling in multiple dimension s for accurately measuring species richness and diversity in tropical forest communities. We discuss the importance of such studies in conse rvation biology. (C) 1997 The Linnean Society of London.