The Herpetological Journal

pp. 155-163
Authors: Tarkhnishvili, David; Kaya, Uğur; Gavashelishvili, Alexander & Serbinova, Irina

Abstract: The Caucasian salamander (Mertensiella caucasica sensu lato) is an endemic taxon of the western Lesser Caucasus, classified as Vulnerable in the IUCN Red List. Two isolated evolutionary lineages occur within its range – one in the Black Sea basin, and the other in the basin of the Caspian Sea. We identified and described 51 locations throughout the range of the species, from the easternmost to the westernmost known location and within an elevational range of 50–2400 m a.s.l. We applied binary logistic regression and a maximum entropy approach to predict the range of the salamander within the polygon delimited by extreme values of 19 bioclimatic parameters for the locations identified. The models were based on the analysis of bioclimatic data, terrain ruggedness and some other environmental variables. The presence or absence of the salamander depends on the level of and variations in rainfall, temperature and terrain ruggedness. Absence of the species from the Greater Caucasus is explained by unsuitable climatic conditions. Separate analysis of the “eastern” and “western” lineages showed no overlap of their predicted ranges, and the model based on the complete data set showed good results only for the “western” evolutionary lineage. This suggests that the genetic isolation of these two lineages is caused by differential climatic requirements rather than by existing fragmentation of suitable habitats.

Keywords: REFUGIA, MERTENSIELLA CAUCASICA, CLIMATIC PREFERENCES, RANGE MODELLING, CAUCASUS