The condition of the ecosystem in the Three-River-Source region has a great deal of influence on the basins of the Yellow River, the Yangtze River and the Lancang (Mekong) River. A research team at the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences estimated the likely situation in the future for ecological services in the Three-River-Source region.
The researchers used a combination of land use change simulation models, climate models, and ecosystem service assessment models to identify possible future scenarios. The possible states of water yields and soil erosion in the future are simulated, and the effect of different land use developments and global climate change on water yields and soil erosion were revealed. The study was published in the Journal of Resources and Ecology.
Most previous studies have focused on analysis of one or several specific ecological services. The current study is broadly based on the characteristics of the study area, historical trends in changing land use and climate change trends, all considered against a background of different human lifestyles.
The researchers designed different future scenarios for land use and climate change, using the Future Land Use Simulation (FLUS) model, and the output data and downscaling correction method of Community Climate System Model v4.0 (CCSM4). The Integrated Valuation of Ecosystem Services and Tradeoffs Tool model was then used to develop scenario simulations of ecosystem water yields and soil erosion in the region.
The study found that under different land use/cover development scenarios, grassland remained the dominant land use/cover type in the Three-River-Source region. With an increase in precipitation, water yields and soil erosion in the Three-River-Source region increased. With a decrease in precipitation, water yields and soil erosion in the Three-River-Source region decreased. Climate change played a leading role in changes of water yields and soil erosion.
The research also showed that a comprehensive regional land use development strategy must consider issues such as regional development, the impact of returning farmland to forest and grassland, and impact of the ecological benefits that result from such efforts.
Spatial distribution of water yield in 2015 (Image by HU Yunfeng's team)