The phenomenon of forest invasion to steppe areas in the Middle Urals and its probable causes

Resumo

Steppes at the northern limit of their distribution are a convenient object for studying climate-induced modifications of the environment, being sensitive to regional climate changes. Over the past 46–47 years, herbaceous vegetation in the study steppe areas has been replaced by shrubs and trees. Petrophytic steppes on hilltops and stony knolls, where conditions are not favorable for tree growth, has proved to be more resistant to such changes. In these habitats, however, the influence of surrounding forest phytocenoses has also resulted in a gradual decrease in the proportions of species from the steppe and forest–steppe floras in the structure of communities and the invasion by species typical of forest vegetation.