Hellena Binz

heallty@web.de


Abundance, richness and composition of butterfly assemblages in creek, slope and ridge rainforest in the Pacific Lowlands of Costa Rica

Tropical rainforests are known to harbour a high diversity of endemic and rare species and, therefore, are of greater conservation value than human modified landscapes. The Piedras Blancas National Park in the Pacific Lowlands of Costa Rica represents one of the last big rainforest remnants in this region.

Our objective was to study the importance of creek, slope and ridge forest for butterfly communities. In total, 140 fruit‐feeding nymphalid butterflies belonging to 33 species were sampled by bait‐trapping, and 578 butterflies belonging to 77 species were recorded by transect runs from November 2009 to February 2010. Species richness of fruit‐feeding nymphalid butterflies increased from creek to ridge forest because of higher proportions of canopy species in slope and ridge forest. Butterflies sampled during transect runs showed lowest species richness in slope forest indicating high dependence on understorey plant density which has been lowest in this forest type. The three forest types differed significantly in their butterfly compositions although several species have been observed in all forest types, mostly represented by common and widespread species.

Fruit‐feeding nymphalid butterflies showed no differences in their morphology between forest types whereas butterflies sampled by transect runs had been biggest in slope forest and manoeuvrability decreased from creek to ridge forest, indicating higher influence of vegetation structure. Most of the recorded butterflies seem to be restricted to the forest type which harbours most of their specific larval host plant family. Our study affirms the importance of different vegetations and locations of forest types, as well as their conjunction for structuring their respective butterfly communities.