Extrazonal desertified steppe vegetation in Ukraine
1Vynokurov D.S., 2Moysiyenko I.I.
1M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine
2Kherson State University, Ukraine
e-mail: phytosocio@ukr.net, ivan.moysiyenko@gmail.com 

Annotation. Desertified steppe vegetation occurs in the southernmost part of Ukraine. There are two distinct types of this type of vegetation: edaphic and climatic. They are represented by the communities dominating by the sagebrushes: Artemisia taurica, A. santonica, A. lerchiana.

One of the most unstudied types of vegetation in Ukraine is desertified steppe. It occurs on the southernmost part of the country, in the lowlands along the Black Sea and along the Sea of Azov, between the Tiligul and Molochna rivers, Tarkhankut and Kerch Peninsulas, and in the Crimean Prysyvashshia. According to the geobotanical zoning of Ukraine, the study area belongs to the Pontic steppe province of the Eurasian steppe region, a strip of sagebrush steppes (Barbarych 1997, Didukh & Shelyag-Sosonko 2003). According to the common approach, this type of vegetation is classified as desert steppes (Bilyk 1973). Average precipitation in this region is about 350-400 mm per year. Soils mostly are chestnut (loam).
We identify two distinct types of the desertified steppe vegetation in Ukraine: edaphic and climatic. The edaphic type is defined by a high salt content in the soil. Such communities are characterized by a number of halophilic species:  Artemisia taurica, A. santonicum, Camphorosma monspeliaca, Limonium gmelinii and others. Such type of vegetation is bordering with Festuco-Puccinellietea class. The most common association is Agropyro pectinati-Artemisietum tauricae Kolomiychuk & Vynokurov 2016, which is spread in the Syvash region. On the mud volcanoes of the Kerch Peninsula, communities of the association Ferulo orientalis-Artemisietum tauricae Korzhenevskij & Kljukin 1991 are found.
The other type of the desertified steppe vegetation is climatic one. It is rarely distributed on the cliffs of the Black Sea, the Sea of Azov and of the estuaries (Dnipro Estuary, Tylihul Estuary, Berezan Estuary etc.). This type of vegetation was not noted before for Ukraine. The dominant species of such communities is a sagebrush Artemisia lerchiana, which has a discontinuous area of distribution. We can assume that these communities are the remains of zonal desertified steppe vegetation which was distributed in this region in historical times.