S.V. Bakka and N.Yu. Kiseleva
Abstract
The present work discusses the scientific and methodological approaches to the study and evaluation of the impacts of habitat fragmentation with elements of human infrastructure (roads, power lines, pipelines) on biological diversity. These elements do not always provoke the isolation of sites, which produces island effects. In the context of the remained natural network, where some fragments of intact habitats have ecological links between themselves and there is an exchange of individuals between the separated groups of species, the dependence of the number of species on the habitat area corresponds to samples. With the destruction of the natural network and the occurrence of insurmountable barriers for living organisms, island effects become to appear between the fragments of remained habitats, and the number of species is decreasing along with the area of habitats at a rate typical for islands. On the basis of the known quantitative pattern allowing the island to be distinguished from the sample, the ways to obtain quantitative estimates and determine patterns for specific types of natural habitats are discussed. The requirements for the selection of model sites and model groups of living organisms are formulated to study the degree of habitat fragmentation. It was found that the priorities in the selection depend on the degree of human transformation of the territory. The protection of least fragmented and intact areas against fragmentation is the most significant. Under conditions of vast areas with the predominance of natural habitats, the fragments of remained intact zonal communities (taiga, coniferous and deciduous forests, oak forests, steppes) are in priority. Under conditions of anthropogenic landscapes, the objects of studies are the fragments of any natural or semi-natural ecosystems (urban forests, parks, grassland slopes, floodplains of small rivers).