High landscape-level gene flow in the red-backed salamander (Plethodon cinereus)

Abstract

Anthropogenic changes are expected to shape the genetic structure of many herpetofaunal populations. Indeed, genetic analyses are often applied in disturbed habitats because they can determine the loss of genetic diversity in isolated populations, identify barriers to dispersal and gene flow, and inform ways in which populations should be managed. As a result, there is a lack of baseline genetic data of organisms in relatively intact landscapes. Plethodontid salamanders are ideal for understanding fine-scale and landscape level genetic structure in continuous landscapes given their high abundance and their sensitivity to ecosystem changes. Given this, our study aimed to assess the landscape-level population structure in red-backed salamanders (Plethodon cinereus) within intact habitat. We investigated genetic variation in 479 individuals from three sites across roughly 26 km of intact hardwood forest. We tested for genetic structure among and within three sites using several metrics, including hierarchical Bayesian analysis, F_ST analysis, AMOVA, and isolation by genetic distance. The results revealed a single population throughout the study area and genetic structure within sites was not evident. Importantly, the sites in this study are part of a long-term project on the effects of standard silvicultural practices in the American Midwest, making it ideal for future re-evaluation of this red-backed salamander population. We now have baseline information to determine if any future disturbances or fragmentation may alter the genetic structure of this population, as well as how this population may change over time if the study area remains undisturbed.