Marmot habitats in the West Tien Shan and their dynmics. Arealy sourkov v zapadnom Tïan’-Chane i ikh dinamika. [Habitats des marmottes dans le Tien Chan occidental et leur dynamique].

Résumé

AIl over their habitat, the marmots of Marmota genus are represented by one vital form and the species are distributed strictly allopathnically. At the same time an analysis of the situation in the West Tien Shan showed changes in habitats of three species historically inhabiting the area. An endemic to the area, Menzbier's marmot (Marmota menzbieri), whose current habitat is mainly associated with ancient raised plateaus, is widely divided in two sites (Kazakhstan and Uzbek-Kyrgyz) that are inhabited in slightly differentiated sub-species. The upper-river Pskem, between the sites, is inhabited by long-tailed marmot (M. caudata). This is the area where Menzbier's marmot specific flea - Citellophilus menzbieri - lives on long-tailed marmot. This fact is a clear evidence of secondary moving in and replacement of Menzbier's marmot by long-tailed marmot. A conception of Menzbier's marmot being forced out by long-tailed marmot from the best habitats (Petrov, 1963) is, in our opinion, incorrect. South of the Chatkal and Fergana ridges long-tailed marmot is replaced grey marmot (M. baibacina). This fact is justified not only by direct observations but the presence of numerous enclaves of long-tailed marmot in practically complete habitat of grey marmot near the habitat's border of these two species. Even here, a specific flea of long-tailed marmot - Citellophilus lebedewi - is found on grey marmot, initially having no fleas of genus Citellophilus. A conception about possible hybridization of these two species here needs correct justification. It should be noted that by size and dimensions of body, also well-justified by shoulder bones analysis, the domination hierarchy of Tien Shan marmot species looks as follows: grey marmot 7 long-tailed marmot 7 Menzbier's marmot. This is a consecution for historical replacement of species habitat, described above. Since recently, a spatial structure of marmots' habitats is significantly affected by anthropogenic activity. First of alI, this is connected with illegal extermination of marmots leading not only to the disappearance of many edge isolates but to catastrophic decrease of populations in main colonies. The most catastrophic is the status of Menzbier's marmot whose habitat is associated with edge and the most accessible mountainous areas. The situation is even more aggravated by restrictions for grazing livestock in nature reserves those results in high growth of grass at marmot's colonies and therefore marmot population in protected areas is constantly decreasing. ln principle, marmots are disappearing in nature reserves. Poorly designed and carried out works on acclimatization of Menzbier's marmot outside its natural habitat, in the Turkistan ridge, did not bring positive results.