Regularities of sinantropization processes of the vegetation cover in the cities of the south Cis-Urals (Bashkortostan Republic)

Abstract

Increase of anthropogenic pressure on nature ecosystems leads to synanthropization of flora and vegetation. A replacement of native species in communities with synanthropic ones, including alien species, takes place as well as a change of native plant communities by synanthropic ones, decrease of biodiversity, simplification of structure, decrease in efficiency and stability of plant communities (Gorchakovskij, 1999). Synanthropization as an indicator of anthropogenic transformation of vegetation is a traditional object of studies (Sudnik-Wojcikowska, 1988; Abramova, 2010; Abramova, Mirkin, 2000; Abramova, Mikhailova, 2003; etc.). The ratio of synanthropic and native flora species for an assessment of synanthropization level is usually used. The assessment of synanthropization level is the most important element of monitoring as it helps to estimate a degree of ecosystems disturbance and to develop a system of their rational use and protection. Processes of synanthropization are most expressed in the towns. The towns are the heterotrophic ecosystems including uniform group of anthropogenically transformed communities formed on the residential, industrial, transport, agrarian, recreational territories where the florogenesis and the phytocoenogenesis are highly specific (Burda, 1991; Ilminskikh, 1993). The urban environment can have the leveling impact on climatic factors therefore the floras of towns in different nature zones quite often have the common features (Ilminskikh, 1993). An increase of a syntaxonomic variety due to destruction of native vegetation is compensated by increase of synanthropic syntaxa number from the synanthropic classes of vegetation, and also communities of aggressive alien species which are combined with species of local flora. The regularities of synanthropization of urban flora and vegetation are less studied (Kowarik, 1990; Burda, 1991; etc.). Due to a growth of urbanization process around the world the studying of anthropogenic transformation of ve­getation cover is required. The article is devoted to the analysis of regularities of synanthropization of plant cover in towns of the southern Cis-Urals belonging to the Southern industrial zone of Bashkortostan Republic. 3 towns — Sterlitamak, Salavat and Ishimbay representing different categories by their population size were chosen for an assessment of synanthropization level.