Year-round activity of peripheral bat populations in the North Carolina coastal plain

Within a species' distribution, there is often a core population that constitutes the majority of individuals. When threats to a species are present, the core populations within the species distribution usually receive the majority of the conservation effort. However, when core populations are threatened, peripheral populations of a species distribution may be critical for conservation. Warmer temperatures along the Atlantic coastal plain may allow peripheral bat populations to remain active through the winter, thereby lowering the probability that they will migrate to hibernacula or wintering sites. Wintering at hibernacula and migrations to wintering sites are both associated with high mortality in multiple bat species because of White Nose Syndrome (WNS) and fatalities at wind farms, respectively. The objective of this study was to determine if, during the winter, peripheral populations of bats in the North Carolina coastal plain are more active than non-peripheral populations. I established four Song Meter recording stations along a 295 kilometer north-south transect in the coastal plain (peripheral sites) and two Song Meter recording stations in the piedmont (non-peripheral sites) of North Carolina I recorded activity every night from sunset to sunrise, during the years 2012-2014. At all sites in both regions (piedmont and coastal plain) there was lower bat activity in the winter compared with the summer. However, winter was the only season where region was a significant predictor, on its own, of bat activity, whereby the coastal plain had higher bat activity in the winter when compared to the piedmont. Moreover, the probability of recording bats during the winter was higher on the coastal plain when compared to the piedmont. In addition, I was able to conservatively identify a subset of my recordings to species. In general, the same species of bats were present in the summer and the winter on the coastal plain. Importantly, bats species that have seen high mortality from WNS, including Myotis septentrionalis and Perimyotis subflavus, were active during the winter in the coastal plain. Increased winter activity of WNS impacted species in peripheral North Carolina populations means these individuals could never come into contact with Pseudogymnoascus destructans (Pd; the fungus characteristic of WNS) spores or could increase their survival should they be infected with Pd. I also found that migratory tree bat species are using the coastal plain and piedmont regions differently with the piedmont likely being used as a stopover point along a migratory route and the coastal plain likely being used as a wintering ground. Of the migratory tree bats, Lasiurus borealis remained present year-round on the coastal plain. On the other hand, Lasiurus cinereus and Lasionycteris noctivagans appeared to migrate, in some cases to the coastal plain. Migration by Lasiurus cinereus and Lasionycteris noctivagans could lead to mortality from wind turbines. My study demonstrates important seasonal differences in activity between coastal plain (peripheral) and piedmont (non-peripheral) populations of bats in the Atlantic coastal plain and underscores the conservation importance of the winter activity of peripheral bat populations