Tropical butterfly communities on land-bridge islands in peninsular Malaysia

Abstract

We sampled and compared butterfly diversity on six land-bridge islands and two comparable control sites in forest on the mainland in Lake Kenyir, northern peninsular Malaysia, from Jun.2007 to Jan.2008 using 123 line transects. We recorded a total of 131 species in five families, three-quarters of which were Nymphalidae and Lycaenidae; nine additional species were observed moving between sampling sites. Butterfly assemblages on the smallest islands included species that tended to be smaller in size, less forestdependant, and were generally more wide-ranging compared to assemblages on large islands and control sites. We supplemented transect sampling with specimens from fruit-baited traps, which caught butterflies on mainland but not island sites. Notably, although control sites and large islands were more species-rich, species assemblages differed greatly among sites, suggesting that butterfly communities were not only weakly nested, but also spatially variable within a small landscape. Effective conservation of intact forest butterfly communities needs to take into consideration high between-site β-diversity arising from habitat heterogeneity even at small spatial scales. © National University of Singapore.