Genetic diversity and structure of two populations of Ambystoma altamirani and A. rivulare of the trans-Mexican volcanic belt.

The most important factor leading to amphibian population declines and extinctions is habitat degradation and destruction. To help prevent further extinctions, studies are needed to make appropriate conservation decisions in small and fragmented populations. The studied mole salamanders are micro-endemic, and their habitat is found in the most ecologically disturbed region in Mexico: The Trans-Mexican Volcanic Belt. The goal of this study was to provide data from the population genetics of two micro-endemic mole salamanders that can be used as a basis for future research and conservation planning of these species and other amphibian species of this region of Mexico. We analysed the genetic diversity and structure, effective population size, the presence of bottlenecks and inbreeding coefficient of 152 individuals from two Ambystoma species. For A. altamirani, two locations were sampled, as well as for A. rivualre; 38 tissues were collected from each locality. We found medium to high levels of genetic diversity expressed as heterozygosity in the populations. However, all the populations presented few alleles per locus and genotypes. Each sampled locality represents a population with a significant level of genetic structure. The effective population size is small but similar to that of the studies from other mole salamanders with restricted distributions or with recently fragmented habitats. Despite the high levels of genetic diversity found, the populations are going through bottleneck processes and their habitats are fragmenting and degrading. Therefore, this study is important to propose better management plans and conservation efforts for these species.