The herpetofauna of Guanajuato, Mexico: composition, distribution, and conservation status

herpetofauna of the Mexican state of Guanajuato currently consists of 24 anurans, three salamanders, 71 squamates, and three turtles, for a total of 101 species. The members of the herpetofauna are categorized among the three recognized physiographic regions of the Central Plateau, the Transmexican Volcanic Belt, and the Sierra Madre Oriental. The total number of species in each of these regions ranges from 60 in the Central Plateau to 75 in the Sierra Madre Oriental. The numbers of species shared among these three regions range from 44 between the Central Plateau and the Sierra Madre Oriental to 56 between the Central Plateau and the Transmexican Volcanic Belt. A similarity dendrogram based on the Unweighted Pair Group Method with Arithmetic Averages (UPGMA) demonstrates that of the three physiographic regions, the Central Plateau (CP) and the Transmexican Volcanic Belt (TVB) cluster at the 0.84 level, and that the Sierra Madre Oriental (SMO) clusters with the other two regions at the 0.65 level. This pattern was expected given that both the CP and TVB are relatively large areas of similar size in the state that lie adjacent to one another; in contrast, the SMO is the smallest region in the state and it is adjoined only to the CP region. The level of herpetofaunal endemism in Guanajuato is relatively high, with 56 of the 101 species categorized as country endemics. The distributional categorization of the entire herpetofauna includes 56 country endemics, 40 non-endemics, and five non-natives. The 40 non-endemic species are placed into the following distributional categories: MXUS (26), USCA (six), MXCA (four), MXSA (three), and USSA (one). The principal environmental threats to the herpetofauna of Guanajuato are agriculture, industry, forestry, cattle production, and mining. We assessed the conservation status of each native species by using the SEMARNAT, IUCN, and EVS systems, of which the EVS system proved to be the most useful. We applied the Relative Herpetofaunal Priority method to determine the rank order of the three regions, which indicates that the Transmexican Volcanic Belt is the region of greatest conservation importance. Twenty-four natural protected areas have been designated in Guanajuato. Fourteen of these areas lie within the Transmexican Volcanic Belt, which is fortunate from a conservation perspective. All but four native species have been documented in these 24 areas. Finally, we provide a set of conclusions and recommendations to help improve the future protection of the Guanajuato herpetofauna.