Ф.В. Фёдоров.
Пространственное распределение и экология бобров Кижского архипелага
Keywords: beaver colonies; role in biocenoses; diet; forage resources; ecological niche
Kizhi Archipelago lies in the northern part of Lake Onego at Zaonezhsky Peninsula (Medvezhyegorsky District). It consists of numerous rocky islets and narrow straits (socalled skerries). Kizhi Archipelago habitats are rich in food for beavers, but cliffy shoreline, stony bottom, and shallow water near the shore are hindrances for the construction of beaver colonies on Lake Onego shores. These characteristics of lakeside habitats – availability of food but lack of habitats suitable for dwellings, force the animals to settle on floating mats: this is where 62.5 % of lodges are situated. This entails another feature of beaver settlement in the Kizhi skerries region – a longer extent of their colonies compared to other parts of Karelia. The time and energy costs of procuring forage and colony engineering are important factors for the vicinity of feeding grounds to the dwelling. As demonstrated by previous studies, beaver colonies in the south and north of Karelia are more “compact” than in the Kizhi skerries, since the animals’ activities are concentrated close to lodges or burrows. Due to lodge construction far away from the forest and to the abundance of small, medium-size, and large islands in the Kizhi skerries, there appear colonies with beaver activities “scattered” extensively along the shores. Food abundance and a simultaneous lack of suitable shelter sites define also some other features of beaver life in Kizhi habitats: larges distances to nearest neighbor colonies, high proportion of re-occupied colonies, high engineering activity, “inconspicuous” alteration of waterside tree stands by the foraging activity of beavers. Beaver numbers in the Kizhi skerries region are expected to remain fairly low, although some potential for an increase in the population does exist.
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