Conservation genetics of an endemic and threatened amphibian (Capensibufo rosei): a leap towards establishing a genetic monitoring framework

Given the ever-increasing anthropogenic changes to natural ecosystems, it is imperative that temporal changes in genetic diversity be monitored to help safeguard the future viability of species. Capensibufo rosei is a small, range-restricted bufonid from South Africa, believed to have experienced an enigmatic decline likely due to the suppression of natural fires and the loss of grazing animals from some areas. Without these disturbances, their habitat becomes overgrown, which might affect the characteristics of their breeding pools. Since the 1980s, four breeding sites have been lost, presumably due to loss of breeding habitat through encroachment of vegetation. Currently, there are only two known populations [Cape of Good Hope (CGH) and Silvermine nature reserves] both within Table Mountain National Park. Consequently, this species may be vulnerable to stochastic events and genetic erosion through the loss of metapopulation connectivity. To assess the genetic status of this species, genetic diversity within both populations was quantified for two time periods using 11 microsatellite markers. Despite evidence of severe population bottlenecks, both populations possess levels of diversity similar to other anurans, and Silvermine has greater diversity than CGH. A close examination of the data revealed both populations to be genetically dynamic through time, with the loss and gain of rare alleles. Both populations also experienced a slight increase in overall diversity between sampling periods. While the latter was not statistically significant, the monitoring period was perhaps too short to understand changes in diversity over time. These results will form the baseline for future monitoring to better understand this threatened and declining species and to track genetic erosion or recovery.