Unraveling natural versus anthropogenic effects on genetic diversity within the southeastern beach mouse (Peromyscus polionotus niveiventris)

Abstract

Anthropogenic habitat loss is among the greatest threats to biodiversity. Populations undergoing fragmentation and loss of habitat are also threatened by erosion of genetic diversity. However, contemporary genetic diversity may be the legacy of natural processes acting prior to anthropogenic influences. Measurements of genetic diversity from contemporary and historical samples can evaluate the relative impact of natural and anthropogenic effects on its status. We investigated the genetic diversity of a threatened subspecies occupying Atlantic Coast barrier islands of Florida, Peromyscus polionotus niveiventris (southeastern beach mouse). To test for recent loss of genetic diversity, we compared cyt b data from museum samples (historical—prior to human impact) with contemporary samples throughout their range. Ten microsatellite loci were genotyped for samples from the contemporary range, to determine current population interconnectedness and structure. The results using cyt b data revealed no statistically significant loss of genetic diversity between historical and contemporary populations of P. p. niveiventris. Both nuclear and mitochondrial data support our conclusion that the observed capture and conservation of historical genetic diversity is explained by the large federally protected region of continuous habitat that remains with minimal human impact. Whereas, the two disjunct populations isolated by anthropogenic habitat destruction, exhibit significant losses of genetic diversity. Collectively, these findings offer a sound basis from which to formulate a conservation strategy to maintain the genetic diversity of P. p. niveiventris. Furthermore, our study underscores the importance of large expanses of continuous habitat within the geographic range of species to facilitate the maintenance of genetic integrity.