Bondariev M. Meadow and riparian ecosystems of the Sula River valley within Sumy Region: flora, populations of medicinal plants and principles of sustainable natural resource management.

The dissertation presents an analysis of the floristic core of meadow and riparian ecosystems of the Sula River valley within Sumy Region, north-eastern Ukraine; a comprehensive population analysis of the model species of promising medicinal plants, Potentilla reptans L. and Potentilla anserina L., along the recreational and mowing gradient; and the substantiation of principles for sustainable natural resource management of these ecosystems, taking into account the ecological consequences of the large-scale war. The study combines floristic, ecological-coenotic, synphytoindication, morphometric, ontogenetic and vitality research approaches. It was established that the floristic core of the studied ecosystems comprises 385 vascular plant species across 194 genera and 50 families; medicinal plant species account for 42,6 % of the floristic composition. The floristic structure is characterized by the leading role of Poaceae, Asteraceae and Cyperaceae, the predominance of hemicryptophytes, and the prevalence of species with Eurasian and European range types. Based on synphytoindication analysis, the ecological niches of the species were characterized according to 12 ecological factors, the relative niche width (RWN) was determined, and groups of species with different levels of ecological plasticity and vulnerability to environmental transformation were identified. For Potentilla reptans and P. anserina as vegetatively mobile forms, individual strategies for maintaining population stability under anthropogenic pressure were established. These strategies are manifested in different combinations of morphometric, ontogenetic and vitality characteristics. To assess the spatial organization of individuals, the Biomass Distribution Index (BDI, %) was proposed. On the basis of the study, principles of sustainable natural resource management were substantiated, including the differentiation of recreational and mowing regimes, conservation of the ecological mosaic of meadow and riparian ecosystems, protection of vulnerable components of biodiversity, use of medicinal plant resources with regard to the state of their populations, and adaptive management of transformed areas.