Countryside Biogeography of Tropical Butterflies

Abstract

Abstract: Although most conservation efforts focus on preserving biodiversity in relatively pristine ecosystems, we investigated possible conservation opportunities in human‐dominated landscapes. We evaluated butterfly diversity in a tropical countryside that was converted about four decades ago from continuous forest to a mosaic of coffee farms, pasture, and forest fragments. We compared the butterfly fauna in coffee plantations with that in a forest remnant, the Las Cruces Reserve (227 ha). We used coffee plantation sites located “near” (<2.5 km) and “far” (>6 km) from the large forest remnant to test the effects of distance from the remnant on butterfly diversity. We also tested the effects of immediately adjacent habitat by selecting coffee plantation sites that were either contiguous with “small” (2.5–9.5 ha) forest fragments (coffee/forest) or lacking adjacent forest (coffee). Both coffee/forest and coffee habitats near the Las Cruces Reserve differed from those far from the reserve in species composition but not in species richness. Overall, coffee/forest habitats had significantly higher mean species richness and higher mean abundance of species than coffee and reserve sites. Further, butterflies with narrow geographic ranges were less likely to be found in coffee plantations than were those with larger geographic ranges. Area of forest cover within a radius of 50 to 100 m of the sampling site was significantly correlated with species richness of frugivorous butterflies during the dry season but was not correlated with richness of frugivorous butterflies in the wet season or of nonfrugivorous butterflies in either season. Nonetheless, species richness of frugivorous and nonfrugivorous butterflies was positively correlated overall; thus, frugivorous butterflies may be good indicators of the status of the entire butterfly community in a region. Our work suggests that small, isolated forest fragments may help retain butterfly diversity in the tropical countryside and increase the conservation value of agricultural landscapes. Relatively large tracts of forest remain important, however, because they maintain rare and endemic species.