Studies on the halophyte desert vegetation in the Northern Caspian Region (Caspian Lowland and Mangyshlak)

Abstract

Halophyte vegetation is a characteristic feature of the temperate desert of Turan, in the Northern Caspian Region - the westernmost part of Turan. It includes the Caspian Lowland and the Mangyshlak. The Caspian Lowland belongs to the steppe and desert regions. The boundary between these Regions runs along the Kuma River on the south-west of the Caspian Lowland (45° N) and further - along the Kuma-Manych Depression and the eastern slope of the Ergeni Height (45° E), reaches 47° N and than turns to the north-east, crosses the Volga river at 48°N and runs to the east along this latitude. The Mangyshlak lies completely within the desert region. It is situated to the south of the Caspian Lowland at the eastern shore of the Caspian Sea between 45° and 42° N. Halophytes play a great role in desert vegetation of the Northern Caspian Region. They form communities that are confined to salted soils and to salted variants of zonal soils. The halophytes comprise a significant number of species, including the families Chenopodiaceae, Poaceae and Asteraceae, together with Tamaricaceae and Limoniaceae. The most numerous is the group of dwarf semishrub halophytes. Some shrub species and two semishrubs are common. Some species of halophilous perennial grasses and one annual grass are characteristic of the desert vegetation. Many species of the annual saltworts also occur. The halophytes can be divided into three groups: (1) those restricted to the solonchak (salt marshes); (2) those restricted to solonetz and takyr; and (3) those with their distribution connected with the salted variants of the zonal soil types. The latitudinal (zonal) and longitudinal (regional) regularities are revealed in distribution of halophytic desert vegetation. Halophyte communities in the desert zone are of a great importance as pastures. There are well adapted to environmental conditions and suitable for phytomelioration of pastures with low productivity.