Regional ecosystem service value (ESV) is significantly influenced by factors such as land use/cover change (LUCC). In this study, from the perspective of spatio-temporal heterogeneity, we constructed a dynamic and zonal equivalence table of ecosystem service values using the equivalence factor method and analyzed the spatio-temporal changes in ecosystem service values of different agricultural plantation regions of the karst mountainous areas of southwestern China (Yunnan Province, YP) in the years from 1990 to 2020. Also, the ESV of YP in 2030 was simulated using the Patch-generating Land Use Simulation (PLUS) model. The results showed the following: (1) land use/land cover (LULC) in YP from 1990 to 2020 was dominated by needle-leaved forestland, broadleaved forestland, grassland, and rainfed cropland. (2) The total ESV in YP fluctuated between CNY 876.74 and 1323.68 B from 1990 to 2020, expanding at a rate of 50.98%. The largest portion of the total ESV comes from climate regulation. The ESV increased from east to west, and the positive spatial correlation of the ESV gradually weakened. (3) The ESV in YP was projected to reach CNY 1320.70 B by 2030, representing a decrease of ~CNY 2.98 B since 2020. The results showed a decline in the ecological environment’s quality in YP.

Understanding the influence of landscape patterns on the water quality of agricultural wetlands is critically important for their management and related decision-making. However, the question of how to quantify this objectively remains a challenge in the relevant scientific fields. In this study, the location-weighted landscape index (LWLI), a process-oriented indicator that integrates ecological processes with landscape patterns based on the source and sink theory, was modified into the SLWLI by assigning nutrient-based weights in the Honghe Hani Rice Terraces World Heritage Site (HHRT). The results indicate that the five watersheds are dominated by sink landscapes, representing 64 percent of the total area. Rice terraced fields were a composite “source–sink” landscape, and their areas in the five watersheds ranged from 4.82 to 20.40%. The nutrient retention function of the sink landscapes of total nitrogen (TN) ranged from 0.64 to 0.86, whereas the total phosphorus (TP) ranged from 0.72 to 0.82, showing good retention function in regard to both nutrients. The contribution rates of forest land and rice terraces to TN and TP retention were greater than 47.07 and 17.07%, respectively, which indicates their key regulation of the nutrient retention function, reducing the risk of water eutrophication and leading to optimized conservation. The vertical pattern of the HHRT plays an important role in nutrient retention function. The SLWLI is an effective index that can be used to assess nutrient retention function and to identify sink landscapes for regulating water pollution in agricultural wetlands.