Optimization of functional zoning and spatial patterns of water conservation on the Qinghai-Tibetan Plateau under different SSP-RCP scenarios

The Qinghai-Tibetan Plateau (QTP) is known as the water tower of Asia, and its water conservation has an important impact on China and even on South, Southeast, and Central Asia. Currently, the water conservation is unstable due to climate and anthropogenic impacts. Strengthening the water conservation of the QTP is crucial for coping with climate change and maintaining the stability of the downstream water supply. Based on the raster data of 2000, 2005, 2010, 2015, and 2020, this study employed the Bayesian network to assess the water conservation on the QTP, and to determine key variables and states that affect water conservation. Finally, we identified the optimized zones under the SSP-RCP scenarios for the years 2021–2100 through grid coding analysis. The results show that: (1) The water conservation of the QTP shows a decreasing trend from the southeast to the northwest. The average value of Yarlung Tsangpo River Basin (YTRB) and Three-Rivers Source Region (TRSR) were 36.47 % and 24.93 % higher than that of the QTP. (2) Precipitation, land use, and potential evapotranspiration contribute more than 1 percent to water conservation and are key variables. (3) The QTP can be divided into four ecological subzones in future scenarios. Among them, the area proportion of ecological conservation zone increases by an average of 7.65 %, and the area proportion of ecological control zone decreases by an average of 8.38 %. Targeted management strategies can be implemented in these distinct zones. The research methodology of this paper can be extended to other regions to enhance water conservation, which has practical guiding value for optimizing the ecological engineering layout and ecosystem management on the QTP.