The thesis is the first special study of the flora of ancient settlements in Ukraine. Floristic research covered 18 archeological monuments within the Lower Dnipro (Southern Ukraine), located on both banks of the Dnipro and its tributaries. The flora of 18 ancient settlements of the Lower Dnipro includes 524 species of vascular plants belonging to 281 genera, 74 families, 3 classes and 2 divisions. The floristic richness in some settlements varies from 124 to 290 species. Structural analysis showed the similarity of the flora of higher vascular plants of the Lower Dnipro settlements to the natural regional flora with typical zonal features. In the geographical spectrum it manifests due to the high participation of species of nomadic-ancient Mediterranean and nomadic geographical elements with a characteristic dominance of aboriginal species, in the biomorphological and ecological structure this similarity is revealed through the predominance of perennial grasses, plants with caudex type of underground shoots, rod type of root system, heliophytes and megathermophytes.
In the course of the study the flora of each settlement of the Lower Dnieper was analyzed and its features were established. According to the results of the statistical analysis, the florae of studied ancient settlements were divided into 3 equal clusters and 13 subclasses of clusters due to the latitudinal soil-climatic gradient. The highest indices of synanthropization of florae were observed in ancient settlements located directly in modern villages (Lyubimivske, Stanislavske, Staroshvedske, Velykolepetyske) or their boundaries (Chervonomayatske, Zolotyi Mys). The sites of ancient settlements with the lowest level of synanthropization are located remotely from modern settlements and are surrounded with vast steppe areas (Konsulivske, Velyke Tyagynske and Sablukivske ancient settlements).
The analysis of synanthropization of the total flora of the ancient settlements of the Lower Dnieper has been carried out. Analysis of the synanthropic fraction (290 species; 55.3% of the total number of species) revealed the predominance of the apophytes over the established alien species (or anthropophytes). The least number of alien species was found on Velyke Tyagynske, Konsulivske, Sablukivske and Skelka settlements, which are quite comparable to the objects of the nature reserve fund of the region. The process of flora transformation is quite moderate, as proved by the prevalence of natural and restored habitats over anthropogenic ones. The main centers of distribution of anthropophytes on the territory of the settlements of the Lower Dnipro are the neighboring agricultural fields, roads, former mining sites, pastures, etc. The general synanthropization index is rather low (IS = 55.3%), both in comparison with the urban flora of cities and with different landscapes of the Northern Black Sea coast. The flora of the settlements of the Wielkopolska Voivodeship (Poland) is characterized by almost the same indices of synathropization, this fact confirmed the high level of preservation of the flora of such archeological monuments, as well as their environmental value.
The dependence of the level of floristic richness of the above-mentioned objects on natural and anthropogenic environmental factors has been studied. The results of regression analysis showed a positive interdependence of vascular plant richness in the settlements with such environmental factors as the habitat variety index, an area, a degree of afforestation and a steppe cover within a radius of 1 km. The distance to settlements is a significant negative factor only for the richness of alien species. Environmental factors such as the habitat variety index and the degree of afforestation were also important for this group.
A significant number of aboriginal (395, 75.4%), steppe (239, 45.6%) and non-synanthropic (223, 42.5%) species of vascular plants were noted on the ancient settlements. Studies have also shown the high sozological value of the studied settlements. Thus, a rare element of the settlements of the Lower Dnipro is represented by 31 species (5.9% of the total number of species). A comparative analysis of the florae of ancient settlements with steppe reserves and other valuable objects of the studied region showed their high representativeness in terms of the percentage of steppe, aboriginal and non-synathropic plants, rare species and habitats. This structure of the flora indicates that the ancient settlements perform well the function of preserving the natural steppe diversity and can potentially be considered as nature conservation sites. The conclusions are of a recommendatory character and determine the ways of optimization of nature use and protection of phytodiversity on the territory of settlements, as well as creation of new perspective objects for nature protection.
