Genetic Diversity in Alabama Gopher Frogs

One major issue facing conservation of small populations is the potential for loss of genetic diversity. As genetic diversity is lost, the fitness of populations may also decrease, reducing the abilities of a population to endure disturbance, disease, or other events (Reed and Frankham 2003). This process is known as genetic drift and can be detrimental for small populations. As amphibian populations are often small with limited dispersal abilities, they are especially vulnerable to drift, particularly when habitats are fragmented and connectivity between populations is lost (Allentoft and O’Brien 2010). There are several ways that populations maintain genetic diversity and variation; genetic variation can be introduced by random mutations in a breeding population, where more breeding individuals increases the probabilities of these mutations, or through transfer of genes from individuals originating in other populations. As populations shrink or become more isolated, this variation can be lost.

One species that may be especially vulnerable to this loss of genetic variation is gopher frogs (Rana [Lithobates] capito). While gopher frogs are capable of dispersing relatively long distances (up to 3.5km, Humphries and Sisson 2012), they are also habitat specialists, requiring fire-maintained longleaf pine uplands as well as fishless, ephemeral breeding wetlands. As longleaf pine forests are now estimated to occur at less than 3% of their original extent (Jose et al. 2006), gopher frogs have lost a large amount of historic habitat, subjecting populations to reductions and isolation. Previous studies have assessed the genetic diversity of gopher frogs in Florida (where genetic diversity remains high, Devitt et al. 2023) and North Carolina (where recent genetic divergence between populations is evident, Arbogast et al. 2022).