Influence of Invasive Plants Parthenocissus vitacea and Vinca minor on Biodiversity Indices of Forest Communities

The distribution and phytocenotic association of Parthenocissus vitacea and Vinca minor on the territory of the Bryansk oblast has been studied. An assessment of the distribution of invasive species is performed on a grid basis. Vinca minor is registered in 19 cells on the territory of the oblast, which is 4.9% of the total number of cells and 11.9% of the surveyed cells; Parthenocissus vitacea is registered in 50 cells, which is 12.8% of the total number of cells and 31.2% of the surveyed cells. The invasive status of Parthenocissus vitacea and Vinca minor is category 3: an adventive species whose invasions into natural and seminatural habitats in the region at the moment are rare and, as a rule, confined to the outskirts of populated areas, abandoned parks, and old plantings. The indices of successful invasion in forest communities is the formation of syntaxonomically valid variants of the communities of Corylo avellanae-Pinetum sylvestris Bulokhov et Solomeshch 2003 with depleted cenoflora. Invasive species change the phytosphere and reliably decrease the indices of α and β diversity, the structural indices of communities. The invasion of Parthenocissus vitacea and Vinca minor is successful due to active vegetative reproduction, allelopathic effects on native species, and decreasing illumination of the ground cover. The introduction of invasive species into complex pine forests blocks demutational changes of endogenous succession during the restoration of broad-leaved forests: they simplify the structure of communities and reduce the intensity of the mosaic. Parthenocissus vitacea and Vinca minor can exhibit signs of an edificator, a community builder, and a violent and transformer type. There has been only one case of a radical transformation of the natural community, registered on the territory of the Lyubin Khutor nature monument (Novozybkovskii district, Bryansk oblast).