Key factors of the ecological niche of himalayan marmot (Marmota himalayana Hodgson (1841) in Nepal. Kliutchevye faktory ekologitcheskoï nochi gimalaïskogo sourka Marmota himalayana Hodgson (1841) v Nepale. [Facteurs clés de la niche écologique de la marmotte de l’himalaya Marmota himalayana Hodgson (1841) au Népal].

Résumé

Ecology of Himalayan marmot was studied in the Central Himalayas (massive Manaslu, Nepal) in 2003, 2004. Four key ecological factors were found: altitude, temperature, relief, feeding conditions. In the Himalayas marmots inhabit areas from upper forest border to snow line (Dobremez, lest, 1976; Shrestha, 1997; Majupuria, Majupuria, 1998; Klatzel, 2001; Nikol'skii, Ulak, 2005) at 3000 rn - 5500 m altitudes, in subalpine and alpine zones (Schweinfurth, 1957; Walter H., Breckle S.-W., 1991). Climate in the areas inhabited by the marmot is relativelyeven (Climates of foreign Asis, 1975), temperature do es not reach the upper critical limit (25°C), which causes stress (Türk, Arnold, 1988; Melcher et al., 1990; Semenov et al., 2001; Copoka, 2001). The most dense marmot settlements are found at alluvial terraces with thick layer of light soil favorable for digging deep, complicated, numerous burrows. Optimum feeding conditions for the marmots are formed thanks to domestic yak pasturing. Yaks eat the tops of young sprouts and thus maintain feeding plants in permanent vegetation mode. Like other marmot species (Abelentswv etc., 1961; Bibikov, 1967; Davydov, 1974; Seredneva, Nesgovorov, 1977; Tokarskii, 1997; Ronkin, Savchenko, 2000), Himalayan marmot feeds on soft growing parts of plants. Currently domestic yaks have replaced the wild ones in many areas of their former habitat; however the manner and scale of effect of the domestic yaks on the vegetation do not differ from those caused by their wild ancestors. Main difference of Himalayan marmot from other marmot species is lower border of its area which lays very high - up to 3000 rn. Plants collected at the marmot settlement in April 2004: Iris potanini, Carex sp., Agrostis sp., Deschampsia sp., Koeleria sp., Taraxacum sp., Saussurea sp., Ranunculus sp., R. hirtellus, Berberis angulosa, Primula sp., Potentilla sp., P. peduncularis, Gentiana sp., Halenia elliphica, Euphrasia himalayca, Polygonum amplexicaulis.