The State of Phytocenoses in Anthropogenically Transformed Landscape of Dry-Steppe Zone in the South of European Russia

Abstract

The modern state of plant communities in the dry-steppe zone of Russia is largely governed by the anthropogenic impact associated both with the agricultural land use and protection of these lands against degradation with afforestation. In Volgograd oblast, 54.7% of the area is involved in the land use for agricultural crop production in the chestnut soil subzone of dry-steppe zone of the European Russia south. Of interest are the late successional stages of the natural phytocenoses that develop on long-term fallows in the conditions of coexistence with artificially established forests and exposure to their effect. These phytocenoses function in altered microclimate, which determines characteristics of the surrounding biota development. Geobotanical studies using geoinformation technologies provide the opportunity to establish phenological characteristics of plant communities’ development on long-term fallows in the anthropogenically transformed landscape. High density of arrangement of tilled fields practically leaves no possibility for steppe vegetation to develop in the favorable conditions. Habitats are displaced to lands unsuitable for tillage, slope lands of more than 8° (subject to the tractor’s passability) low in humus and fertility, and shallow in terms of soil conditions; to eroded sites; and slope areas adjacent to the network in the shallow groundwater zone with aggradational soils of gullies and arroyos; as well as to fallow land. As a result of the geoinformation research, an effect of the adjoining forest plantations is established on characteristics of herbaceous phytocenoses development at the late successional stages on long-term fallows in the chestnut soil subzone of dry-steppe zone of the Russian Federation. Investigation of seasonal dynamics of vegetative development of the phytocenosis Elytrigia repens (L.) Nevski + Poa bulbosa L. in dry-steppe zone in chestnut soil subzone considering an exposure to a stretch of the state protective forest belt “Kamyshin—Volgograd” shows that in the inter-strip space of the belt in the destructive zone, productivity of aboveground portion of herbaceous vegetation is reduced by 23% relative to the control site in the beginning of the investigation period in May, but practically coincides with the control in June.