Ecological-coenotic structure of the pine forest flora at the southern margin of the geographical range of Pinus sylvestris L

Abstract

The ecological-coenotic structure of pine forest flora was compared at the southern margin of the geographical range of Pinus sylvestris. The Usmansky and Khrenovsky (Voronezh and Lipetsk regions), Krasnosamarsky and Buzuluksky (Samara and Orenburg regions) pine forests were investigated. The species diversity of vascular plants in the studied forests included also the alien and introduced species. The coenotic structure reflects the zonal location of the pine forests and their current state. The zonal coenoses are resistant for the penetration of alien species. The meadow component brings the most number of species into the plant diversity of the pine forests (23.3-25.2%). The pine forests, located in forest-steppe zone (Usmansky and Khrenovsky), are characterized by high species diversity of the forest and pine-forest component (20.4% and 20.2%), while in Buzuluksky and Krasnosamarsky pine forests, located in the steppe zone, it is significantly lower (19.6% and 15.7%, respectively). Meantime, the steppe component is more pronounced in the pine forests located in the steppe zone of the Trans-Volga Region (Buzuluksky, 21.9%, and Krasnosamarsky, 24.8%), while in forest-steppe pine forests Khrenovsky and Usmansky, it is quite lower, 16.4% and 15.5%, respectively. In the Usmansky pine forest, every third alien species of vascular plants is of cultural origin (escapee), in Khrenovsky and Buzuluksky, every fourth, and in Krasnosamarsky, every fifth species.