Terrestrial algae of hypersaline environments of the Central Syvash islands (Kherson Region, Ukraine)

In hypersaline environments of the Churiuk and Kuyuk-Tuk islands located in Central Syvash lagoon (Ukraine) 93 species of oxygenic phototrophs (49 Cyanoprokaryota, 29 Chlorophyta, 12 Bacillariophyta, 2 Xanthophyta, 1 Streptophyta, 1 Eustigmatophyta) are recorded. The sites studied represent four basic types of habitats: semi-terrestrial ecotone (littoral heavy-loam solonchak free of vascular plants), wet gleyic solonchak covered by sparce halophytic vegetation, gleyic solonetz under saline meadow vegetation, and chestnut solonetzic soil with Steppa salsuginosa formation. They differ in the taxonomic composition and species diversity of algae. The highest species diversity is observed at sites of wet gleyic solonchaks (71 species of five divisions), the lowest diversity (23 species belonging to three divisions) in the harsh littoral ecotone. The distribution and abundance of species in the four habitats are discussed with reference to their ecology. Descriptions and original drawings of noteworthy taxa of Chlorophyta and Xanthophyta are presented.