Habitat use by two species of Mongolian marmots ( Marmota sibirica and M. baibacina) in a zone of sympatry

Abstract

The spatial segregation of Siberian marmots Marmota sibirica Radde, 1862 and grey marmots M. baibacina Katschenko, 1899 in the zone of contact in Mongolian Altai (47-degrees-30'N, 90-degrees-50'E) and habitat use by Siberian marmots at Aj Bogd Uul mountain (44-degrees-43'N, 95-degrees-10'E), where only this species occurs, were studied with the use of discriminant function analysis. In the zone of sympatry the Siberian marmots inhabit productive highland valleys, whereas the grey marmots occupy only tops of ridges reach of alpine vegetation. Three of the four localities where marmots intermediate in coloration and call were observed are characterised by suboptimal conditions (unproductive slopes of ridges). A pronounced niche shift towards the habitat of ridge tops and a slight expansion of niche breadth were found in the allopatric populations of Siberian marmots.