Range-wide Population Genetic Structure of Rafinesque's Big-eared Bat (Corynorhinus rafinesquii) and Southeastern Myotis (Myotis austroriparius)

Vannatta, Jessica

ABSTRACT: Understanding underlying genetic structure is essential for the conservation and management of rare or uncommon species because it is important to protect the evolutionary potential and adaptability of a species by preserving genetic diversity. Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii or CORA) and Southeastern Myotis (Myotis austroriparius or MYAU) are two uncommon bat species with overlapping ranges across much of the southeastern United States. At the state level, both species are regarded as threatened, endangered, or species of greatest conservation need across nearly all of their range. The overall objective of this study was to examine genetic structure and genetic diversity of CORA and MYAU populations by determining levels of population connectivity across the range. I collected tissue samples from 860 individual bats (CORA = 366, MYAU = 494) from 75 sites, 14 states, and 11 ecoregions that span the range of both species. I extracted and sequenced nuclear and mitochondrial DNA using genotyping-by-sequencing (GBS) and mitochondrial DNA (mtDNA) using Sanger sequencing. GBS results indicated CORA has at least two, if not three, disjunct populations corresponding to coastal and plains ecoregions and more inland ecoregions with a moderate degree of genetic differentiation. CORA populations from the Middle Atlantic Coastal Plain and Southeastern Plains ecoregions in North Carolina and Virginia should be considered a separate management unit (MU) from the rest of the population. It would be beneficial to create artificial roosts and natural forest corridors to reconnect populations and promote genetic connectivity within each MU. In contrast, GBS results indicated that MYAU is a single, well-mixed population with little genetic structure. Results from mtDNA indicated higher levels of genetic structure for both species, but especially CORA who may be exhibiting sex-biased dispersal. Genetic diversity estimates were low to moderate for both species. Forearm length was greater in females than males and differed by ecoregion for females of both species. Results from this study can be used to infer and improve long-term protection and management protocols for CORA and MYAU. In addition, researchers and managers will be able to use this information to determine how to protect populations of these two species by promoting gene flow, especially for disjunct populations of CORA.