干旱区生态环境知识资源中心

We conducted the first inventory of ants on the Islas Murcielago, Area de Conservacion Guanacaste (ACG) of Costa Rica. We conducted this study on a chain of seven islands and a nearby mainland site, southwest of the Santa Elena Peninsula, northwestern Costa Rica. We collected ants during three different seasons throughout one year, using three techniques; pitfall traps, Winkler sacks, and opportunistic collecting by hand. We determined ant species richness and composition for all islands and the mainland site. We also evaluated the relationship between island area, distance from the mainland, and relative vegetation cover with the number of ant species recorded on each island. We found a total of 50 species of ants on the Islas Murcielago and 34 species on the mainland (combining results from standardized and non-standardized sampling). Thirteen species of ants found on the mainland were not recorded from the Islands. Distance and area did not explain ant species richness on the Islands. Ant species composition varied for each island, and we documented fluctuations in ant presence throughout different seasons. We found two exotic species on the Islands, but in relatively low abundances and coexisting with other species. Considering the extreme seasonality of the Islas Murcielago and the desert-like environment in the dry season, we found a higher number of ant species than we expected. It is unclear what factors best explain patterns of species richness and composition on the Islands, though human impacts likely contribute.