Densité et structure démographique de la marmotte à tête noire (Marmota camtschatica Pall.) dans le Nord-Est de Ïakoutie. The density and demographical structure of the black-capped marmot (Marmota camtschatica Pall.) in the North-Eastern Yakutia.

Résumé

The main centres of the black-capped marmot inhabitats in Yakutia are situated in Verkhoyan, Chersky, Momsky mountain ranges. Population density varies from 3 to 19, average species number is 9 individuals per 100 km2. Marmot concentrations reach 13 individuals per 10 km2 in the most favourable places of Kharaulakh mountains (S=54 sq. km) and 9 individuals in Central Verkhoyan (S=72 sq.km). Quantity of one colony is 8-23 mammals of different ages. The basis of colony are 1-5 families. The marmot's family consists 3-6 individuals (average number-4.6) in Kharaulakh mountains and 2-7 (average-4.5) in Central Verkhoyan. 42% of all marmots live one by one or in pairs in Kharaulakh, and 57%-in Central Verkhoyan. Adults form 35.6% of the colonies, marmots older, than 2 years old, but sexually immatured-10.2%, individuals at one year old-10.2%, and juveniles- 44% of the colonies in Central Verkhoyan. Only 2-4 cubs (average-2.9) survive at the end of summer in Kharaulakh mountains, 1-5 cubs (average-2.8) in Central Verkhoyan. Maximal registred age of the marmot in Kharaulakh mountains is 6 years old.