Population genetic structure of the great fruit-eating bat (Artibeus lituratus) in Atlantic forest remnants in South America

Background/Question/Methods . Agriculture and ranching have replaced huge areas of Atlantic forest over the last century, resulting in large-scale reduction of this rare and diverse ecosystem. Understanding the impacts of anthropogenic landscape modifications on population viability is fundamental for conservation. In tropical and subtropical ecosystems, bats are often the most abundant mammalian species, and have evolved intimate relationships with many plant species. Their high mobility and abundance make bats crucial in the dispersal of many plants and connectivity of forest communities. Phyllostomids are an especially diverse and abundant family of New World bats, making them good models for investigating population connectivity. However, little is known about the impact of habitat fragmentation on their population structure. We aim to test how patterns of landscape use, particularly forest loss and resultant fragmentation, have influenced genetic variation within the widespread frugivorous bat Artibeus lituratus. We measured the distribution of microsatellite genotypes in highly fragmented (Paraguay) and relatively pristine (northeastern Argentina) Atlantic forest. We characterized genetic structure within and among sites using F-statistics and Bayesian clustering algorithms, and used Mantel tests to estimate genetic isolation by geographic distance among localities for sites in continuous and fragmented forest, respectively.

Results/Conclusions . Preliminary results found low but significant pair-wise F_ST values and a (non-significant) trend for positive isolation by distance for sites in fragmented forest. In contrast, sites from continuous forest showed no discernible genetic structure. Bayesian clustering indicated two populations in the region, and the boundary was located in the fragmented forest landscape of Paraguay. These preliminary results reveal how genetic variation is partitioned across continuous and fragmented forest. They also suggest that, even for a potentially highly vagile species, fragmentation can have a rapid effect on population subdivision. Further analyses including more microsatellite loci will allow us to improve resolution, and make inferences about how fragmentation, as well as other environmental characteristics, drives genetic structure of bat populations across landscapes.