Author: ARMANDO SUNNY GARCIA AGUILAR
Ambystoma leorae (TAylOR, 1943), is endemic to the “Sierra Nevada” mountains of central México. its known distribution (Figs. 1A, 1B) is restricted to six locations within the protected area “iztaccihuatl Popocatepetl National Park” (iPNP). The salamander was originally described from the town of Rio Frio (TAylOR 1943); later it was recorded in three sites surrounding the area (vEgA-lóPEZ & AlvAREZ 1992; lE MOS-ESPiNAl et al. 1999), and in another two southern sites (lEMOS-ESPiNAl & AMAyA EliAS 1985; vEgA-lóPEZ & AlvAREZ 1992). These records are restricted to the upper tributaries of the Balsas River in the west of the iPNP, dispersed within an area of about 28 km x 0.65 km.
Autonomous university of the State of Mexico (3530/2013MT)
Articulo producto parcial de tesis doctoral
Land use and climate change are affecting the abundance and distribution of species. The Trans-Mexican Volcanic Belt (TMVB) is a very diverse region due to geological history, geographic position, and climate. It is also one of the most disturbed regions in Mexico. Reptiles are particularly sensitive to environmental changes due to their low dispersal capacity and thermal ecology. In this study, we define the important environmental variables (considering climate, topography, and land use) and potential distribution (present and future) of the five Thamnophis species present in TMVB. To do so, we used the maximum entropy modeling software (MAXENT). First, we modeled to select the most important variables to explain the distribution of each species, then we modeled again using only the most important variables and projected these models to the future considering a middle-moderate climate change scenario (rcp45), and land use and vegetation variables for the year 2050 (generated according to land use changes that occurred between years 2002 and 2011). Arid vegetation had an important negative effect on habitat suitability for all species, and minimum temperature of the coldest month was important for four of the five species. Thamnophis cyrtopsis was the species with the lowest tolerance to minimum temperatures. The maximum temperature of the warmest month was important for T. scalaris and T. cyrtopsis. Low percentages of agriculture were positive for T. eques and T. melanogaster but, at higher values, agriculture had a negative effect on habitat suitability for both species. Elevation was the most important variable to explain T. eques and T. melanogaster potential distribution while distance to Abies forests was the most important variable for T. scalaris and T. scaliger. All species had a high proportion of their potential distribution in the TMVB. However, according to our models, all Thamnophis species will experience reductions in their potential distribution in this region. T. scalaris will suffer the biggest reduction because this species is limited by high temperatures and will not be able to shift its distribution upward, as it is already present in the highest elevations of the TMVB.
Universidad Autónoma del Estado de México: 4047/2016SF. CONACYT
Human activities are affecting the distribution of species worldwide by causing fragmentation and isolation of populations. Isolation and fragmentation lead to populations with lower genetic variability and an increased chance of inbreeding and genetic drift, which results in a loss of biological fitness over time. Studies of the genetic structure of small and isolated populations are critically important for management and conservation decisions. Ambystoma rivulare is a micro-endemic Mexican mole salamander from central Mexico. It is found in the most ecologically disturbed region in Mexico, the Trans-Mexican Volcanic Belt. The goal of this study of the population genetics of the micro-endemic mole salamander was to provide information to be used as a basis for future research and conservation planning of this species and other species of the Ambystoma genus in Mexico. The structural analysis found two subpopulations, one for each river sampled, with no signs of admixture and very high levels of genetic differentiation. Medium to high levels of heterozygosity and few alleles and genotypes were observed. Evidence of an ancestral genetic bottleneck, low values of effective population size, small inbreeding coefficients, and low gene flow were also found.
The Universidad Autónoma del Estado de México funded the study (3047-2011E). R.L.H-B is grateful to CONACYT and COMECYT (359990 and 16BTID0028) for scholarships.