Agroclimatic conditions of habitats and morphometric characteristics of Heracleum mantegazzianum Sommier & Levier (Apiaceae, Apiales) in the Western Caucasus

During our route surveys, few habitats of Heracleum mantegazzianum Sommier & Levier were identified in the Karachay-Cherkess Republic and Krasnodarsky region. Analysis of climatic data have shown that within its native range in the Western Caucasus, the optimal conditions for the growth and development of this species occur at elevations ranging from 700 m to 1300 m asl. The limiting factors for its dispersal are the duration of the period with stable snow cover and snow depth, which determine the possibility of seed stratification and the risk of cold damage to overwintering plant organs. In its natural habitats in the Caucasus, such plants occur singly or in groups of up to 30–50 individuals. In disturbed habitats, the species forms monodominant stands with foliage projective cover close to 100 %. Plants enter the reproductive phase at the age of 2 to 4 full years. The height of generative H. mantegazzianum individuals reaches 3.5 m, and the mass of the largest plants ranges from 11 to 20 kg, which is comparable to the characteristics of individuals of this species in its invasive range. Voucher specimens of H. mantegazzianum collected in the Western Caucasus are deposited at the SYKO scientific herbarium (https://ib.komisc.ru/add/herbarium).