Marking activity of common beaver (Castor fiber L.) in the settlements of channel type. Dynamic aspect

Abstract

Features of the marking activity of beavers in the channel-type settlements are considered. On the basis of statistical data it was determined that the signal hillocks may be recommended for investigation of dynamic indexes of scent marking by beavers. On the basis of quantitative methods the role of the level mode of water streams in the appearance of olfactory marks is demonstrated; as a result, the inversely proportional dependence between these parameters has been revealed.The evermore increasing area occupied by technogenic systems makes the problem of natural population control more and more acute. Regulation of the number and spatial distribution of key ecosystems and animals of exploited population group remains the most topical. Measures on direct extermination provide short-term effect which ecological value remains underestimated [1][2][3]. The best results are achieved by the methods of biological control influencing the animals'receptor systems with the view of obtaining certain behavioral response [4][5][6]. However, wide application of such methods requires additional investigation of animals' orientation means, their methods of exhibiting territoriality and signaling. It is well-known that for the majority of mammals the leading role in communication between species and their aggregates belongs to chemical signals [7,8]. Castor fiber (Linnaeus, 1758) is a convenient object for investigation of the issues of olfactory communication. Unlike other model species which behavior was studied (sable, mink, musk-deer, field-vole, etc.) it does not mark the territory with fecal matter [7]. The product of beavers' preputial organs and secretion of anal glands are characterized by easily identified smells and are laid (in the majority of cases) on specific substrate [9].Despite a significant number of works related to scent marking of the species there are many ambiguous statements, contradictory data and unexplored aspects [10,11]. Besides there are data indicating limited extrapolations of investigation results in the beavers' family (Castoridae) due to reliable differences in changeability of scent marking, in chemical composition of specific glands' secretion and lability of adaptation mechanisms of different species [12][13][14]. In territorial behavior of the animal uniformity of settlement use and timing of different marks to its spatial and functional parts and infrastructural elements remain unclear; the role of tropical factors in appearance and renewal of olfactory marks has not been clarified. Despite numerous data on the diverse methods of olfactory signaling (on the ground, hillocks, parts of trails and prominent subjects) in all known works [9, 15-17, etc.] except for [18] marking behavior of beavers was described only on signaling hillocks.The objective of this research is to study the features of marking activity of beavers in channel-type settlements. To reach the objective it is necessary:-to study regularities of dynamics of different types of olfactory marks; -to determine the most regul...