ИСТИНА

Arid wetlands are recognized as the temporary inundated territories, located in the zones of arid and semi-arid climate which are the habitats for very specific and diverse ecosystems. Representing the local biodiversity hotspots, the arid wetlands may be called as ‘the lands of contrasts’ where over-moistened territories are adjacent to deserted areas. Among all the wetland types, arid wetlands are the most sensitive to environmental changes and human impact, as they are often the only source of fresh water and other natural resources in arid regions. They are of a great social importance in terms of ecosystem services, and they are critical in regional and local biodiversity conservation in arid or semi-arid lands. Desertification and freshwater ecosystem loss, occur in response to climate change, environmental disturbances and human impact are the most urgent problems in many arid wetlands, so its monitoring by remote sensing is crucial not only for understanding of their functioning and seasonality, but also for the development of the standards for the wetland estimation, land use regulation, and prediction of the response of wetland ecosystems to the future environmental changes. Generally, the following basic research fields for satellite imagery application for wetlands exist: delineation and inventory of wetlands, habitat mapping and monitoring, ecosystem health estimation (seasonal and long-term dynamics, biomass estimation), desertification monitoring and land use monitoring (change detection). This overview is based mainly on the methodologies of original researches on satellite data applications in the large arid and semi-arid wetlands located in lower flow of the rivers Volga, Terek,Sulak (Russia), lower Ural (Kazakhstan), and Indus River (Pakistan).