Morphophysiological variability of small mammals of the Khindiktig-Khol depression

Results of morphophysiological variability study of small mammals of Hindiktig-Hol hollow in high mountain massif of Mongun-Taiga (South-West Tuva) are presented. A total of 224 adults of three mass species of the genus Lasiopodomus, Alexandromys (Microtus) oeconomus and Alticola were studied. Comparative characterization of exterior plastic and interior morphophysiological traits of populations of Lasiopodomus gregalis, Alexandromys oeconomus and Alticola strelzovii inhabiting identical habitats on Hindiktig-Khol Lake Island and on the mainland showed that complex factors and auto-regulating population mechanisms differ. Morphofunctional adaptations of small mammals of island and mainland populations are complex and ambiguous. It was established that morphophysiological parameters of species populations have variability towards decrease in mass and body length and increase in indices of internal organs on mainland, while on island populations of the same species have opposite relations - increase in mass is associated with decrease in indices of internal organs. Biogeochemical studies of soils and vegetation cover of the main biotopes of small mammals revealed high content of some heavy metals both on the island and on the mainland, which may be a factor determining the direction of adaptive capabilities of organisms. Morphophysiological variability manifested in mainland and island populations of the studied species should be considered as cases of genetic assimilation of morphoses adaptive to physical and chemical conditions of the study area.