The impact of multi-scenario land use change on the water conservation in central Yunnan urban agglomeration, China

As an important ecosystem service, water conservation is consistently disturbed and influenced by human activities. Land use change, as one of the main human influences, has extensive and far-reaching impacts on water conservation. Therefore, it is of great practical significance to accurately assess the impact of future land use changes on water conservation. Taking the central Yunnan urban agglomeration (CYUA) as an example, coupled with the PLUS-InVEST model, four scenarios of natural development (NDS), urban development (UDS), cropland protection (CPS) and ecological protection (EPS) were set to simulate the impact of land use change on water conservation under different planning scenarios in 2035, revealing the response mechanisms to land use change. The results showed that (1) under different planning scenarios, there were obvious differences in regional land use changes, and the expansion effect of construction land under the NDS, UDS, and CPS was significant, with increases of 27.54%, 27.95%, and 21.19%, respectively, compared with 2020. Under the EPS, the expansion rate of construction land was effectively controlled, and the growth rate was only 0.64%. (2) The EPS optimized the water conservation capacity of the CYUA, while the regional water conservation capacity showed a varying declining trend under the NDS, the CPS and the UDS. (3) The occupation of grassland by construction land and forestland was the main reason for the deterioration of the water conservation function of the urban agglomeration in central Yunnan. The results of this study can provide a reference for national land space planning, the efficient use of land resources and ecological environmental protection of the CYUA.