Ecological and Floristic Features of Pioneer Grass Vegetation on Automorphic Sandy Soils as a Pine-Forest Recovery Phase in the Southern Part of the Nonchernozem Zone of Russia

Abstract

This article addresses the phytocoenotic diversity of psammophytic grass communities in the southern part of the nonchernozem zone of Russia, where the restoration of Scots pine (Pinus sylvestris) is either ongoing or potentially possible. Community structure and composition formation trends developing under the influence of key environmental and coenotic factors have been identified. The studies were carried out in Bryansk, Kaluga, and Smolensk oblasts in 2010–2018; over 150 geobotanical releves of psammophytic grass communities have been produced. This vegetation belongs to the class Koelerio-Corynephoretea Klika 1931, which combines dry grasslands on sandy soils and rocky outcrops in the temperate and boreal zones of Europe, on islands of the North Atlantic, and in Greenland. Differences between environmental regimes of various habitats occupied by psammophytic communities have been identified. In most cases, the environmental amplitudes of syntaxonomic units vary significantly by the three key edaphic factors (moisture, soil reaction, and soil richness in mineral nitrogen) and form pretty compact environmental spaces: within each syntaxon, numerical values of the above factors, expressed in score points, normally vary within a narrow range. Regression analysis has established that the species richness of psammophytic communities depends statistically significantly only on the mineral nitrogen supply and soil moisture. Based on the statistical analysis results, the number of Pinus sylvestris plants of any age does not depend on the species richness in the community, total projective cover of the grass stand (excluding the Scots pine), separately calculated moss and lichen projective covers, and average numerical values of environmental factors identified by H. Ellenberg in the community. It is established that numbers of pine trees on study sites depend on only one factor: distance from the diaspora source determining the invasion possibility. The data on the phytocoenotic and floristic diversity of the psammophytic grass vegetation are to be incorporated into the unified database on the southern part of the nonchernozem zone of Russia to identify environmental and botanical–geographical features of this plant community type in the region.