Article du Bulletin
Biodiversity and distribution areas of the Transbaikalian marmots in the past [Biodiversité et aires de distribution des marmottes du Transbaikal dans le passé].
Erbajeva M. · 2008 · In abstracts of the VI marmot meeting, Marmots in a changing world, 3.
Résumé
Marmota sibirica is typical steppe dweller species. According to the fossil data from the Transbaikal area the ancestral form of this species appeared in the region during the Middle Pleistocene, around 0.8 MA. It was described from the Dodogol locality as Marmota sibirica nekipelovi Erbajeva, 1966. The earliest record of the Transbaikalian marmot had arisen to the Middle Pleistocene (Marmota tologoica) when in the region was distributed savanna-like forest-steppe with Hipparion fauna. With progressive cooling and aridization of the climate paleoenvirnment had changed towards dry and warm. Mosaic type landscapes of the Late Pleistocene were replaced by open landscapes with meadow-steppes and dry steppes of the Early Pleistocene and semi-deserts and deserts for the Middle Pleistocene. Marmots were rather abundant, however the dominant elements in the faunas were Allactaga, Eolagurus, Meriones, Ellobius, Ochotona – inhabitants of extremely dry environment. Towards Late Pleistocene climate in the region continue to be arid, but more continental influence of the further cooling as in Northern Hemisphere. It is resulted in wide distributions of periglacial arid steppes which probably were favourable habitat for marmots of the Transbaikal area. The dominant forms in the faunas were Marmota sibirica, Asiopodomys brandti, Ochotona daurica, Microtus fortis, Lagurus lagurus and Cricetulus, the first of which was widely distributed in the Transbaikal area and was represented by a number of diverse taxa which was widely distributed in the Tranbaikal area and was represented by a number of diverse taxa which differ by peculiar characters probably even of the subspecies level. During the Holocene the climate changed towards more humid and warm which led to decrease of open areas and widening of forest-steppe landscapes. As a result the distribution area of Marmota sibirica became more limited.