The least-cost path analysis of landscape genetics identifies two dispersal routes for the threatened Kaiser's mountain newt (Caudata: Salamandridae)

Variation in landscape features plays an important role in shaping the distribution of species in natural populations. These can influence population connectivity, gene flow, genetic drift, and ultimately the genetic structure and diversity of isolated populations. In this study, we aimed to identify the impact of landscape heterogeneity on the dispersal patterns of the threatened Kaiser’s mountain newt, Neurergus kaiseri. We integrated population genetics and geospatial data to predict the rates and patterns of genetic differentiation as well as to identify potential movement corridors among populations. For this purpose, we used two mitochondrial DNA markers and combined data on genetic subdivision (θ_ST) and least-cost path (LCP) analyses from 15 fragmented highland streams and spring-ponds representing the entire species distribution area. Five possible dispersal routes used in this study were straight-line, stepping-stone, least cost slope, stream likelihood and combination least cost slope/stream likelihood. Genetic and LCP analyses indicated that two clades in the northern and southern distribution range have experienced two differing dispersal routes. The newts identified through the northern populations with high genetic diversity have dispersed with stepping-stone movements. In contrast, the southern populations are more isolated and dispersal might be facilitated by aquatic corridors in the least cost slope. We suggest that this study allows new implications for the conservation priorities of N. kaiseri by estimating the potential dispersal activity of the species in the face of climate change and ongoing habitat destruction relating to human activities in the southern Zagros mountains of Iran.