Ecological niche differentiation among three subspecies of the vulnerable Russian tortoise Testudo horsfieldii through its distribution range

Abstract

Hosseinian Yousefkhani S. S. 2023. Ecological niche differentiation among three subspecies of the vulnerable Russian tortoise Testudo horsfieldii through its distribution range 2023. Folia Biologica (Kraków) 71: 171-180. T. h. horsfieldii, T. h. rustamovi and T. h. kazakhstanica – are all allopatric. In the present study, the ecological niche divergences among three subspecies were evaluated using a bioclimatic dataset. Suitable habitat predictions and niche similarity tests indicated that the three subspecies have significantly different ecological niches. Temperature is an important factor for the presence of a subspecies, but the threshold is different for each subspecies. Temperature appears to limit the range for the northern subspecies T. h. kazakhstanica, but not for the two southern subspecies T. h. rustamovi and T. h. horsfieldii, which have relatively wide ranges in Central and Southwest Asia. Local adaptations to distinct climates and the microevolution process may have played important roles in this differentiation. It is recommended to evaluate these subspecies using molecular markers, in order to estimate the demographic relationships amongst them and to make taxonomic decisions.