Spatial genetic structure of Lissotriton helveticus L . following the restoration of a forest ponds network

Preserving amphibian genetic diversity through ecological restoration and conservation actions is a major challenge since their populations are declining worldwide. We studied the genetic diversity and spatial genetic structure of the palmate newt (Lissotriton helveticus) 2 years after the restoration of a pond network in northwestern France with the aim of reconstructing fine-scale genetic structure and patterns of colonization. We sampled newts from 29 forest ponds including both restored and non-degraded reference ponds, and genotyped 391 individuals at 12 microsatellite loci. We used two Bayesian clustering methods to spatially delineate genetic clusters, and we also detected potential recent migrants within the network. All ponds showed low levels of observed heterozygosity (Ho = 0.534) and a mean F IS of 0.251, possibly indicating a Wahlund or bottleneck effect. Pairwise F ST suggested limited evidence of genetic differentiation among ponds. Within the pond network, we identified 3 to 4 genetic clusters. Combined with the detection of migrants, the results suggest an increase in gene flow within the restored pond network and that a high number of migrants came from the reference ponds. Our findings indicate an unexpected high dispersal ability for this small-bodied species. Overall, the absence of population structure represents a positive beginning for the restoration project. It also emphasizes the importance of spatial design in restoring a pond network and that such genetic data and methods should be used to monitor amphibians in restored habitats.