Temporal and Spatial Evolution and Driving Force Analysis of Water Conservation Function in Yunnan Province Based on Climate and Land Use Change

[Objective] Exploring the water-holding function is an important way to cope with future climate change. Existing research mainly focuses on the assessment of historical and current water-holding function, and lacks the understanding of the future water-holding function, which limits the value of guiding the sustainable development and dynamic management of the region. [Methods] Taking Yunnan Province as an example, this paper combined the system dynamics model, patch-level land use change simulation model (PLUS model), and InVEST model to build a water conservation evaluation framework under the impact of future climate and land use change. The framework can predict land use change and assess water conservation in the context of future climate change and different economic developments. Water conservation in Yunnan Province was evaluated based on the coupling scenarios of three shared socioeconomic paths and typical concentration paths (SSP1-1.9, SSP2-4.5, SSP5-8.5). The main driving factors of temporal and spatial changes in water conservation in Yunnan Province were identified by using the optimal parameter geodetector. [Results] (1) From 2000 to 2030, the total area of cultivated land and unused land decreased, the area of water area and construction land increased gradually, and the forest land and grassland changed in a wavy line; The trend of land use change in different scenarios is roughly the same, namely: grassland > construction land > cultivated land > unused land > water area > forest land. (2) From 2000 to 2020, water conservation showed a gradually decreasing trend, decreasing by 2.27×109m3; Under the influence of different climate and land use models, the water conservation under different scenarios is different, and the water conservation under the SSP2-4.5 scenario is the highest, which is 9.338×109m3. The spatial distribution pattern is “high in the southwest and low in the northeast”. (3) The results of geographical detection show that the average annual precipitation, soil type, and DEM are the main driving factors affecting the spatiotemporal distribution difference of water conservation, and the interaction between precipitation and other factors is significantly enhanced. [Conclusion] According to the temporal and spatial differences in water conservation in Yunnan Province, different suggestions were put forward in this study to provide scientific reference for ecosystem service research and sustainable development route planning in Yunnan Province.