Potentilla incana P. Gaertn., B. Mey & Scherb. (Rosaceae) coenopopulations vitality structure at Southwest Opillya

Potentilla incana P. Gaertn., B. Mey & Scherb. – is the medium-east European species that grows on sand, granite, limestone, chalk and plains of the most part of Ukraine. In South-West Opillya P. incana is met infrequently – mostly on steep southern and south-eastern slopes of the hills and bedrock exposure of rim gypsum. Sometimes species acts as dominant of the lower tier groups. In the studied coenopopulations P. incana in terms of South-western Opillya there are the individuals of all classes of vitality, but in the ratio between classes there are significant differences. Predominance of the part of individuals of the highest class of vitality is characteristic for five coenopopulations, in other three coenopopulations the amount of these individuals varies within 40-44%. Coenopopulations of all three types of vitality are represented in the territory of study. In particular, two of coenopopulations from the tract “Rocky-floristic reserve” and two of coenopopulations from Bystritsa-Tlumach natural area belong to prosperous type; 2 coenopopulations – are equilibrium, and others – are depressive. Quality index of coenopopulations acuires the highest value in the tract “Rocky-floristic reserve”, and slightly lower one – in the tract “Zhdymyr”. The lowest value of Q index is observed in the tract “Velyki Holdy”. Analysis of eco-cenotic conditions showed that the prevalence of upper class vitality individuals and high index value of quality are characteristic for coenopopulations P. incana, that grow in groupings of formations Cariceta humilis and Festuceta valesiacae at the podzolized chernozem, power capacity 25-35 cm, formed on relatively sloping parts of the south-eastern hillsides. Prosperous coenopopulations include also coenopopulations in groupings of formations Festuceta valesiacae and Stipeta capillatae on thin soils with deposits of rim gypsum. In coenopopulations P. incana, growing on bedrock exposure of rim gypsum formations in groupings of formations Festuceta valesiacae, Stipeta capillatae, Stipeta pulcherrimae, the part of individuals of low vitality class is significantly higher. However, the projective cover of individuals of P. incana at bedrock exposure of rim gypsum is considerably more and is 50-90%, and on the soil – from 5 to 30%. The average values of projective cover of P. incana individuals are observed in equilibrium coenopopulations at bedrock exposure of rim gypsum (50-60%). With the increasing density of individuals up to 80-90%, index of coenopopulations quality is significantly reduced.