During an ecological expertise the vegetation of Tuzla Spit and Tuzla Island, located in the middle part of the Kerch Strait (Fig. 1), was studied. This area is unique in terms of biological diversity and a presence of rare species (Ermolaeva et al., 2018).
The study is based on 150 geobotanical relevés. Field data, topographic maps, and high-resolution satellite images were used in the vegetation mapping. The total area of the study is 383 hectares. There are the following hierarchical levels in the legend to the vegetation map: types of vegetation and classes of associations. A mapping unit is an association described according to the Braun-Blanquet system (Braun-Blanquet, 1964). The highest divisions of the legend are the types of vegetation: aquatic, coastal-aquatic, halophytic, psammophytic, steppe; they are given according to the ecological-phytocoenotic classification. Within the types of vegetation, classes of associations are given according to the ecological-floristic classification. 26 main numbers of the legend display the vegetation cover on the map. Geobotanical map reflects the state of vegetation in 2015 (Fig. 2).
The vegetation of the island is heterogeneous. Plant communities as narrow stripes replace each other depending on the degree of moisture, salinity and orography. The sea currents have a great influence on the vegetation. In the southern part of the Taman Bay, suspension flows are directed from the South to the North and round the island, which leads to the “washing-up” of the southeastern part of the island represented by shallow waters and estuaries. It is occupied mainly by halophytic vegetation, the main dominants of plant communities are Juncus maritimus, Phragmites australis, Puccinellia distans, Bassia hirsuta, Salicornia perennans, S. prostrata, Suaeda salsa, Elaeagnus angustifolia, Elytrigia elongata, Tripolium vulgare. The northwestern part of the strait is occupied by the area of jet streams of suspensions coming from the North to the South from the Sea of Azov. This caused the accumulation of sand-shell material in the northern and northwestern parts of the island forming raised areas covered by psammophytic and steppe communities. The main dominant species here are Crambe maritima var. pontica, Cakile euxina, Eryngium maritimum, Lactuca tatarica, Salsola tragus, Leymus sabulosus, Artemisia arenaria, Gypsophila perfoliata.
As a result of the transport crossing construction, the vegetation cover was heavily transformed. The vegetation map of Tuzla Spit and Island for 2019 shows the changes that have occurred — the drainage of the territory and the reduction of the vegetated area (Fig. 3). Distribution of weed species, in particular Ambrosia artemisiifolia, is noted.
The remained vegetation in the southern part of the Tuzla Spit and the southern part of the Tuzla Island has a great nature conservation value; there are unique plant communities and rare plant species listed in the Red books of different ranks (Red..., 2007, 2008, 2015): Cakile euxina, Crambe maritime, Glaucium flavum, Euphorbia paralias, E. peplis, Eryngium maritimum, Astrodaucus littoralis, Asparagus maritimus, Centaurea arenaria, Argusia sibirica, Astragalus varius, Verbascum pinnatifidum, Leymus racemosus subsp. sabulosus, Secale sylvestre. There is an obvious need to organize a specially protected natural area in these areas.
Transformation of Geosystems of the Northern Part of the Baikal Natural Territory (Research and Mapping)