Fragmentation of habitat can decrease resource availability and restrict movement among geographic areas. Persistence in fragmented landscapes depends on the maintenance of connectivity among populations, without which genetic diversity may decrease and lead to population declines. Bees are particularly vulnerable to the negative effects of low genetic diversity, so it is important to understand patterns of dispersal for native bees living in fragmented areas. I used population genetic techniques to characterize patterns of genetic diversity and dispersal for the orchid bee Euglossa imperialis within and among forest fragments in southern Costa Rica, in which the furthest two fragments were 226 km from one another. I assessed the independent contributions of geographic distance and land cover to variation in genetic distance among fragments. In addition, I compared results of population genetic analyses conducted with all bees sampled, and results from analyses conducted with a reduced dataset containing only one individual per full sibling family from each site.
Results/Conclusions
For both datasets genetic diversity was low within forest fragments, with expected heterozygosity averaging 0.28 for the full dataset and 0.29 for the dataset containing only one full sibling per site. Genetic and geographic distance were correlated in the full dataset, and there was no evidence that deforested areas restrict dispersal. I discuss how habitat loss-driven resource limitation may promote dispersal in this system, as well as the implications of these results for future conservation monitoring of E. imperialis.