The study deals with the characteristics of the vegetation of National Nature Park «Dzharylhatsky», in particular, the analysis of flora, classification of vegetation, identification of the main dynamic trends and development of conservation measures.
The floristic composition of vascular plants of NPP «Dzharylhatsky» includes 365 species of vascular plants, 235 of them were found on the island Dzharylhach, 267 – on mainland areas of the park.
According to the results of a systematic analysis of the flora, it was found that the island Dzharylhach due to its isolation from the mainland and large area in comparison with other islands of the Black Sea (56.5 km2) has a greater species diversity than the transformed mainland areas. The change in the spectrum of leading families over a 90-year period indicates a decrease in the influence of the grazing pressure, which had a significant impact on the formation of the island vegetation in the early XX century.
Biomorphological analysis confirmed that significant synanthropization processes are observed on the mainland, and moderate – on the island, caused by afforestation and naturalization of several species. Comparison of proportion of different biomorphological groups over time indicates the extinction of natural species of trees and shrubs on the island.
An analysis of the leading environmental factors – salinity and humidity affected the development of flora, was made for the recent and historical flora of the island in order to confirm the expected effects of global climate changes. Over the 90-year period, the processes of xerophytization and halophytization have been prevailed.
An аnalysis of the synanthropic fraction of the studied flora shows a significant transformation of the continental areas, where the synatropic fraction predominates over the natural one.
The classification scheme of the vegetation includes 19 classes, 24 orders, 27 alliances, 66 associations, three subassociations, 12 derivative and two basal communities.
Three new for science associations were described. Two associations, one alliance, one order and one class are new for Ukraine. Seven classes, six orders, seven alliances, 18 associations, three subassociations, 13 rankless communities have been revealed in the NNP «Dzharylhatsky» for the first time.
A 1:10000 scale vegetation map of island Dzharylhach has been developed. The map shows the territorial differentiation of vegetation. It has also been used to reconstruct the island vegetation changes over the past 20 years. A comparison of cartographic materials revealed that the predominant processes in vegetation cover are halophytization and xerophytization of communities.
The main trends of vegetation dynamics of the NPP «Dzharylhatsky» are overgrowth of sand and halophytic communities by certain species and communities. This is due to the instability and dynamism of ecosystems in natural conditions, which are vulnerable due to the processes of sand movement and catastrophic changes even without the intervention of recreational or economic activities.
12 associations and three communities on the basis of ecological and floristic classification on the territory of the NNP were considered as rare. Three formations based on dominant classification from the Green Data Book of Ukraine were revealed.
The scientific novelty of the work is that for the first time, a checklist of the flora of vascular plants for the territory of the National Nature Park «Dzharylhatsky» was compiled, it includes 365 species from 227 genera and 69 families; the taxonomic composition of the modern and historical flora of the island Dzharylhach was established, its systematic, biomorphological, and ecological structure was clarified, the synanthropic fraction of the NNP flora was analyzed.
For the first time, a classification scheme of vegetation was developed and a prodrome of vegetation was compiled, the latter includes 19 classes, 25 orders, 28 alliances, 66 associations, three subassociations, 12 derivative and two basal communities.
For the first time representativeness of the existing and projected objects of the nature reserve fund which are subordinated to park was analyzed.
For the first time a large-scale (1:10000) map of vegetation of the island Dzharylhach was created. It is based on an interactive project in the open software QGIS. It will also be of practical importance, as it provides an opportunity to conduct further monitoring studies of vegetation changes on the basis of this project. This will significantly speed up further mapping and increase the accuracy of the obtained data.
The obtained results are used for editions of the Chronicle of the nature of NNP «Dzharylhatsky». Recommendations for optimizing the territory of the NNP (clarification of functional zoning) were transferred to the relevant state institution – the Department of Ecology and Natural Resources of Kherson region.
