Long-distance movements of small mammals during the autumn-winter period

Abstract

First time in the East Urals radioactive trace zone (EURT) (Chelyabinsk region, Southern Urals) small mammals from natural population with rhodamine B (RB) label, received in last year were revealed. The aim of this study was to estimate long-distance movements (LDM) of small mammals during the autumn–winter season by method of group marking with bait containing RB. One-time ingestion of bait with RB ensures systemic marking, which fixed in keratin-containing structures (hairs, claws, vibrissae). Retention time of RB-label for wood mouse (Sylvaemus uralensis Pallas, 1811) was 338 days, for common shrew (Sorex araneus Linnaeus, 1758) – 312 days, for red-backed vole (Myodes rutilus Pallas, 1779) – 251 days. It has allowed for the first time to estimate LDM of wintering individuals during autumn–winter season from EURT zone to adjacent territories and vice versa. It was found that S. uralensis are able to settle within 10800 m, M. rutilus – 9500 m, S. araneus – 9300 m. These data are the maximum recorded distance for these species. There is a predominance of females both among wintering settled animals and distant migrants. Probably LDM of females is evolutionary more favorable to population as they serve as the potential reserve of a genetic variety. LDM provides spatial and functional connectivity of mouse-sized mammal’s populations and possibility of genetic information exchange between population groupings on both the impact and background territories. The technique of group marking with bait containing RB has shown the efficiency at research of spatial structure of small mammals during the autumn-winter period. It is advisable to include it in monitoring system in areas of local technogenic pollution as well as to use it to calibrate samples of animals in the study of remote effects of radiating and other toxic effects.