LAUSR

The distribution of the Sosnovsky hogweed on the southern border of the secondary range in the European part of Russia on the example of the Kursk Region is investigated in the work. It is revealed that Sosnovsky hogweed grows mainly in the western part of the Region in the vicinity of places where it was cultivated in fields in the second half of the twentieth century. The analysis of invader occurrence in anthropogenic and natural ecosystems of the Region revealed patterns of distribution that are characteristic of invasive species at initial stages of their secondary range formation: most of the foci are present in anthropogenic and semi-natural habitats; medium-sized foci predominate (from 100 sq. m. to 1 ha); the greatest number of foci was found in the areas located along roads. The intensive distribution of hogweed in settlements of the Region, especially with pronounced depopulation processes, was revealed. Among natural and semi-natural habitats, most of the foci were found along the banks of reservoirs. In forests, hogweed is found mainly in small groups of vegetative rosettes on the outskirts, with the exception of areas with a strong anthropogenic impact, where multiple foci with generative shoots are formed. At present, hogweed is not found on arable land due to the intensive cultivation of agricultural land in the Region. Plant communities with Heracleum sosnowskyi in the Kursk Region are represented by 4 syntaxons: association Urtico dioicae-Heracleetum sosnowskyi , association Rudbeckio laciniatae - Solidaginetum canadensis variant Heracleum sosnowskyi , association Chelidonio-Aceretum negundi variant Heracleum sosnowskyi , derivative community Heracleum sosnowskyi [ Agropyretalia intermedio-repentis ].