Landscape genetics of the Southern Flying Squirrel (Glaucomys volans) in the northeastern United States

Understanding how changes in landscape properties influence common species is relevant as it allows us to identify patterns that could be shared with co-distributed species that occupy the same landscapes. The northeastern United States (NE-USA: New York state and the six states of New England) is heavily urbanized and affected by continuous and prolonged anthropogenic activities, leading to intensive landscape fragmentation and loss of natural forests. Here, we used a landscape genetics approach to explore the genetic diversity and structure of the Southern Flying Squirrel, Glaucomys volans, and how resulting patterns may be related to landscape fragmentation and forest loss in the NE-USA. To study G. volans genetic variation and population structure, we amplified and genotyped 10 microsatellites loci from DNA extracted from tissue samples stored in biological collections and natural history museums. To assess the influence of landscape on gene flow and connectivity, we used two genetic distances metrics-proportion of shared alleles and codominant marker, and tested two landscape cost models approaches-least cost path and isolation by resistance. We identified three genetic clusters, with low but significant genetic differentiation between them. We did not find correlation between geographic distance and genetic variation in these populations. According to landscape models, land cover and elevation were the best predictors of genetic connectivity of G. volans, although were poorly related to genetic distances. Our results suggest that gene flow occurs between G. volans populations across the NE-USA despite the changed landscape configuration, implying potential dispersal of individuals between patches. Nonetheless, individuals from the eastern periphery of the distribution may have been temporarily isolated in the past due to historical deforestation. The current regeneration of hardwood forests represents a positive outlook for the genetic integrity of G. volans populations in the NE-USA because more possibilities for corridors and patches of habitable forests emerge. These changes would improve the connectivity of the species in the region and avoid possible local extinction events.

Automated summary

Understanding the genetic diversity and structure of the Southern Flying Squirrel in the heavily urbanized northeastern United States is important for assessing the impact of landscape fragmentation and forest loss on common species. Through a landscape genetics approach, we found that gene flow occurs between populations despite landscape changes, but individuals at the eastern periphery may have been temporarily isolated in the past. The regeneration of hardwood forests presents a positive outlook for the species' genetic integrity and connectivity in the region.