Genetic diversity and structure of two endangered mole salamander species of the Trans-Mexican Volcanic Belt

Víctor Ávila-Akerberg,Rosa-Laura Heredia-Bobadilla,Octavio Monroy-Vilchis,Martha M. Zarco-González,Armando Sunny

doi:10.3897/herpetozoa.32.e38023

Abstract

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 goal of this study was to provide data from the population genetics of two micro-endemic mole salamanders from the Trans-Mexican Volcanic Belt. Nine microsatellite markers were used to study the population genetics of 152 individuals from twoAmbystomaspecies. We sampled 38 individuals in two localities forA. altamiraniandA. rivualre. 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. We found strong genetic structure between populations for each species. Effective population size was small but similar to that of the studies from other mole salamanders with restricted distributions or with recently fragmented habitats. Despite the medium to high levels of genetic diversity expressed as heterozygosity, we found few alleles, evidence of a genetic bottleneck and that the effective population size is small in all populations. Therefore, this study is important to propose better management plans and conservation efforts for these species.

Highlights

In Mexico, the Trans-Mexican Volcanic Belt (TMVB; Fig. 1A) is one of the most ecologically disturbed regions of the country and is highly fragmented by urban settlements, roads and agricultural areas (Sunny et al 2017; González-Fernández et al 2018)
The first population of A. rivulare was in Corral de Piedra (19°13'6.60"N, 99°57'54.77"W, with an altitude of 2,836 MASL), and the second population was in Raíces (19°9'37.26"N, 99°49'32.11"W, with an altitude of 3,225 MASL), both of which are in the Nevado de Toluca Volcano (NTV)
We found medium to high levels of genetic diversity expressed as heterozygosity in both species and all the populations (Ho = 0.576–0.754)

Summary

Introduction

In Mexico, the Trans-Mexican Volcanic Belt (TMVB; Fig. 1A) is one of the most ecologically disturbed regions of the country and is highly fragmented by urban settlements, roads and agricultural areas (Sunny et al 2017; González-Fernández et al 2018). The TMVB is the most important region in terms of endemic amphibian and reptile species and the second most important in terms of the number of species (Flores-Villela and Canseco-Márquez 2007) It is one of the most disturbed areas of Mexico, with 44.7% of the TMVB highly fragmented by agricultural lands, 3.4% by urban settlements and 25.3% by roads. These anthropogenic activities are creating small patches of natural habitats and this scenario could start reducing the genetic flow between the populations of amphibians and reptiles of the TMVB (Lowe et al 2005; Honnay and Jacquemyn 2007; Herrera-Arroyo et al 2013). The International Union for the Conservation of Nature (IUCN 2017) has recognized genetic diversity as one of the three levels of biological diversity necessary to conserve species diversity (McNeely et al 1990; Frankham 1998; IUCN 2017)

Objectives

Methods

Results

Conclusion