Natural and semi-natural land dynamics under water resource change during 1990-2015 in the Tarim Basin, China

Tarim Basin is one of the typical arid areas with the most severe desertification from natural and semi-natural land in the world due to the limited water resource. However, the knowledge about the impacts of water resource changes on the spatio-temporal dynamics of natural and semi-natural land is still limited. We analyzed the spatio-temporal changes in natural and semi-natural land and the associations with desertification in the Tarim Basin during the 1990-2015 period. We then investigated the water resource change and its impacts on the spatio-temporal changes of natural and semi-natural land using the integration of Gravity Recovery and Climate Experiment (GRACE) territorial water storage (TWS) and field observations. The results showed that a total area of 10.32×103 km2 natural and semi-natural land was converted to the desert during the 1990-2015 period. Desert-vegetation type and saline type were the most sensitive natural and semi-natural land converting to the desert. Natural and semi-natural land area decreased by 0.83% every year, and desertification area proportion was 34.79% on average during the 2000-2010 period, less than that of the 1990-2000 period (1.14%/y and 52.01%) due to increased availability of water resources through the water conveyance program. However, the decreasing rate of natural and semi-natural land area (0.93%/y) and desertification area proportion (58.88%) rose again during the 2010-2015 period because of the rapid decrease in water resources. The natural and semi-natural land area loss rate (-7.89%) in the decreased water resource region was about two times that in the increased water resource region (-3.88%) during the 2000-2015 period, highlighting the critical role of water resources in maintaining the natural and semi-natural land and slowing desertification.