Land-use change and land degradation in Turkmenistan in the post-Soviet era

The Central Asian Newly Independent States have experienced dramatic political and economic changes over the last three decades. Despite these changes, significant areas of the drylands in this region have not been studied since the 1980s. Landsat images acquired before and after the collapse of the Soviet Union, were analyzed to evaluate land-use/land-cover changes and desertification processes in northern Turkmenistan. Vegetation and crust indices, albedo, and spectral mixture analysis, supplemented by field work, were applied to estimate the long-term degradation/re-growing of vegetation cover.The major land-use change identified was an 86% increase in irrigated agricultural areas, equivalent to a loss of about 4500km² previously available for natural pastures. Pastures adjacent to the irrigated (and populated) areas were not affected, and in many places, increased vegetation cover was observed. The main degradation processes in these pastures are flooding and technogenic desertification; both occur around man-made structures. Remote pastures have experienced a higher degree of vegetation degradation, mainly due to the development of soil biogenic crust. These observations emphasize the controversy and variability of land degradation processes in this region: distant pastures show a degradation trend, while closer to populated areas, there are signs of rehabilitation.