Trans-Volga–Trans-Ural Steppes of the Northern Subzone of the Steppe Zone: Features of Modern Formation Diversity

Abstract

A significant part of the natural Trans-Volga–Trans-Ural Steppes in the northern subzone has been destroyed by plowing. At the same time, they are represented over a rather large area by deposits of different ages. It is known that communities of many formations are distributed throughout the steppe zone. The differences in the structure of undisturbed communities in different subzones are quite clear. These differences hard to distinguish on deposits and pastures. Having studied the vegetation cover of the steppe zone for many years, we set a task in 2018 and 2019 to identify the way in which the formation diversity changes on deposits and the extent to which the deposit structure can be used to assess the subzonal status of the territory. The studies were carried out with the route method. More than 150 geobotanical releves were made according to the standard method with reference to coordinates. The ecological–phytocenotic classification was used for the analysis of releves. More than 1000 herbarium sheets with reference to coordinates were collected. Instead of zonal Stipa zalesskii steppes Stipa capillata steppes currently dominate being the background vegetation on the deposits in the Trans-Volga–Trans-Ural part of the Northern subzone.Along with steppes of Stipa capillata, secondary steppes of Stipa lessingiana occupy large areas. A peculiar component of the vegetation cover of the northern subzone is created by dwarf semishrub communities. They are confined to saline soils or rock outcrops. Halophytic and petrophytic variants of the steppes are represented not only by dwarf semishrub communities but also by perennial forbs. New data on the distribution of a number of rare species were obtained in the course of the floristic research.