The State of the Beaver (Castor Fiber) Population and Characteristics of Beaver Sites in Eastern Lithuania

Abstract

To estimate the state (amount, density) of the beaver population and characteristics of beaver sites in the landscapes of hilly morainic uplands and sandy plains in Eastern Lithuania, beaver sites and signs of beaver life activities were cartographed in flowing and stagnant water bodies. The investigations were carried out in 1997, in 40 accidentally chosen 1-km2 squares, in which, in addition, the character of shoreline vegetation, water bodies and their banks was estimated. The territorial density of beaver sites in the investigated region was established to be 0.23 pcs./km2, i.e. twice the height of the one indicated in the official report of the Ministry of Environment (Record of hunting animals and birds, 1997). Based on that it was calculated that there should be 5915 beaver sites or 23600 beavers in the whole area of both the landscapes. In sandy plains, the water bodies suited to live for beavers were mostly lakes (60%), while in hilly morainic uplands – flowing waters (88%). The landscapes notably differed in the shoreline biotope structure of water bodies (open biotopes prevailed in hilly morainic uplands) and in soil structure (sand and peat soil predominated in sandy plains). In sandy plains, beavers most often lived in lodges (83%), while in hilly morainic uplands – in burrows and semi-lodges (75%). Besides, beaver sites in both the landscapes often differed in length, length of canals dug by beavers, and relative number of dams. Those and other characteristics of beaver sites were resulted in by a type of water bodies.