Life in a mosaic landscape: Anthropogenic habitat fragmentation affects genetic population structure in a frugivorous bat species

摘要

Bats are often considered highly mobile and hence less susceptible to habitat fragmentation than other animals. We tested this basic assumption by studying populations of Dermanura watsoni, a frugivorous phyllostomid bat, inhabiting forest fragments in an agriculturally dominated landscape in northeastern Costa Rica. We used the mitochondrial D-loop DNA-sequence data to examine genetic diversity and population structure. A significant population differentiation (F_(ST) = 0.05, p < 0.001) over a geographical scale of approximately 20 km was detected. Genetic diversity within fragments correlated with patch size and the amount of suitable habitat in the surrounding matrix. The composition of the matrix in close proximity to the fragments explained variation in genetic diversity best. However, only habitat parameters measured from 1986 land cover conditions can explain current genetic diversity, and not those from 2001. Our study demonstrates that bats, despite their high mobility, are not secure from genetic erosion in anthropogenically modified landscapes. Population differentiation can occur on a surprisingly small geographic scale and after short time periods. Our findings illustrate the importance of considering several points in time when testing for an influence of habitat parameters as it might be decades until they are reflected by genetic diversity.