Abstract
The aim of the study is to inventory the current composition of the flora of the Yelanetsky Steppe Nature Reserve, Mykolaiv Oblast, Ukraine, to analyze its structure for the first time, and to characterize the role of the reserve in conserving the floristic diversity of the steppe zone of Ukraine. It was established that the reserve’s spontaneous flora includes 692 species and subspecies, of which 542 are native and 150 are alien. The systematic, geographical, biomorphological, and ecologico-coenotic structures of the flora were analyzed, and found to reflect the steppe nature of the reserve’s vegetation cover. The geographical spectrum of the native flora was dominated by Eurasian Steppe (26.3%), Mediterranean (18.8%), and Eurasian (17.9%) geographical elements. Twenty-four species and subspecies are endemic. Most alien plant species (54.0%) originate from the Mediterranean region. In the biomorphological structure of the native plants, hemicryptophytes dominate (57.2%); among alien plants, therophytes prevailed (50.7%). The greatest threat to the reserve’s steppe ecosystems is posed by high-impact invasive woody species: Acer negundo, Amorpha fruticosa, Elaeagnus angustifolia, Fraxinus pennsylvanica, Robinia pseudoacacia, and Ulmus pumila. The Yelanetsky Steppe Nature Reserve was shown to play a crucial role in conserving forb–grass steppe ecosystems in southern Ukraine.