Genetic and phenotypic comparison of natural and translocated populations of a pond‐breeding amphibian

Translocations are a commonly used method in conservation practice and are often viewed as successful if a new population persists. However, there is a need to understand the genetic and demographic consequences of translocations to better understand why some translocations are successful while others fail. Using a spatially structured population of the natterjack toad ( Epidalea calamita ) from northern Switzerland, this study presents a genetic and phenotypic analysis of natural and translocated populations. We used microsatellites to analyze the genetic structure (genetic diversity, differentiation, gene flow, and bottlenecks) of 102 individuals from 5 natural/donor and 64 individuals from 3 translocated populations. To study phenotypes (i.e., life history traits and behavior) of individuals, we used a common garden experiment. All genetic diversity metrics showed no genetic differences between natural and translocated populations with more genetic variation within than among populations. Although we found signatures of bottlenecks, they did not seem to have significantly affected genetic diversity of both natural and translocated populations. Life history traits of tadpoles (i.e., mass at metamorphosis, days to metamorphosis, survival) and behavior (tadpole activity) were similar in natural and translocated individuals. We conclude that the translocated populations have a genetic structure and life history traits similar to the donor and natural populations in the area. Overall, the results suggest that the approach used in this translocation program (individuals were taken from multiple donor populations and multiple females within populations and a large number of tadpoles in late developmental stages was released) was successful because it led to the establishment of populations that had levels of genetic diversity comparable to natural populations.