Burlaka M. Extinction risk assessment of endangered vascular plants of European broad-leaved forest zone of Ukraine

The thesis is devoted to extinction risk assessment of endangered vascular plants of European broad-leaved forest zone of Ukraine: Diphasiastrum tristachyum, Diphasiastrum zeilleri, Linnaea borealis, Pedicularis exaltata, Sesleria caerulea and Spiranthes spiralis. Current distributions of the species in Ukraine were revealed (two new subpopulations of Spiranthes spiralis were described). We investigated their population parameters (number and density, vitality, spatial and ontogenetic structure, where appropriate), ecological and coenotic characteristics. An improvement of multiparametral vitality analysis was suggested. This will make easy comparison of research results' for different taxa or authors. Coenotic structure and ecoareals of the species within Ukraine and Europe were described by the means of synphytoindication and compared using discriminant analysis. Based on these data there were elaborated values of Ya. P. Didukh ecological scales for two species and were improved for the others. For the first time were assessed risks of extinction for examined species under the regional IUCN Red list criteria within Ukraine. Diphasiastrum tristachyum and D. zeilleri are classified as Near Threatened due to low values of area of occupancy and extent of occupancy. Linnaea borealis meets the criterion B2ab(iii,v) as it has only two localities and both number and area of populations have declined. Pedicularis exaltata belong to category Endangered in Ukraine under criterion D (number of mature individuals are less than 250). Population of Sesleria caerulea within Ukraine meets criterion D2 for Vulnerable species because there is a single locality with area less than 20 km2. And Spiranthes spiralis is classified as Endangered taxon under criteria A2c and С2а(і) as its populations have declined in the past and the number of mature individuals in each subpopulation is less than 250. The most threatened among considered species in Ukraine are Linnaea borealis, Pedicularis exaltata and Spiranthes spiralis. The major threats for model species are proximity of their localities in Ukraine to the areal border (for Diphasiastrum tristachyum, D. zeilleri, Linnaea borealis), limited areas of suitable biotopes (for all model species), possible transformation of present biotopes due to excess (for all model species) or lack of anthropogenic influence (for Pedicularis exaltata, Spiranthes spiralis).