Landscape pattern variation, protection measures, and land use/land cover changes in drinking water source protection areas: A case study in Danjiangkou Reservoir, China

Understanding the changes and interactions between landscape patterns and land use/land cover (LULC) in drinking water source protection areas (DWSPAs) is fundamentally important for effective land management to ensure landscape sustainability and the protection of water quality. However, there is limited research on LULC changes, landscape patterns and the relationship between them in DWSPAs. This study focused on the DWSPAs of the Danjiangkou Reservoir, one of the most important water sources in China. Four LULC maps (2000, 2005, 2010, and 2015) were extracted to study the temporal-spatial relationship between landscape patterns and LULC. According to the results of the change processes and trends, a series of dramatic changes occurred in the LULC, including percentage decreases in cultivated land (10.31%) and water bodies (20.23%) and a percentage increase in built-up land (116.96%). A comprehensive index for Status, Direction, and Trend with a value of 0.66 indicated an imbalanced and one-way transition in the study region. The Aggregation index metric decreased from 98.2885 to 98.2120, and the Simpson's diversity index metric increased from 0.7161 to 0.7369, which suggested a diversification and fragmentation of the landscape trends. The relationship analysis revealed that the changes in the LULC due to protection measures were the driving factors of the variation in landscape patterns, especially in cultivated land and water bodies. These insights on LULC changes, landscape pattern variations, and temporal-spatial relationships have important implications for future land-use planning polices and environmental activities.