Rare diversity of forest vegetation of the steppe zone: current state, threats and directions of changes

Abstract

Under the action of various forms of human activity, there was a violation of the integrity and unity of the vegetation cover of the steppe zone of Ukraine. The consequence of this is the fragmentation of vegetation. It was established that the decrease in the area of plant communities leads to an increase in their dependence on environmental factors. An important component of the phytocoenotic cover, and first of all the forest cover, which is the biotic basis of the functioning of the biosphere, its evolution and maintenance of an ecologically balanced state, is a rare phytocoenofund. The purpose of the work was to compile information on the current state of rare groups in the steppe zone using data from ecological and coenotic studies, sociological analysis and assessment of the latest threats to rare forest diversity. A critical analysis of the current rare phytocenophyte, the data of modern synphytosozological studies and the latest geobotanical information on the rare phytocenotic diversity made it possible to establish a modern rare phytocenophyte of the forests of the steppe zone of Ukraine. It has 16 associations of three formations. The sociological analysis showed that all phytocoenoses of 16 rare forest associations are characterized by a rare type of association, are located on the border of the range, and 5 associations are formed by an endemic species. According to their sociological status, they are divided into rare (4 associations) and endangered species (12 associations). The potential for natural recovery of populations of dominant species of groups in specific ecological conditions is very weak or weak in all 16 rare forest associations. Currently, rare forest communities are most negatively affected due to the complete loss or fragmentation of habitats, pollution, overexploitation of species and ecosystems, competition from populations of adventive species, global climate change and unbalanced development of forestry, military actions.