Quantitative evaluation on the impact of the Sloping Land Conversion Program on landscape pattern of land use in Karst area

By the implementation of the Sloping Land Conversion Program in Puding County, which is characterized as the special Karst region, the land use/cover pattern has been confirmed to be greatly altered with the improvement of ecological environment in the region. In this study, we analyzed and evaluated the effect of the Sloping Land Conversion Program on the landscape patterns and land use types by methods of principal component analysis (PCA) based on three series of Landsat TM images in 1999, 2003 and 2009. The results showed that: 1) in 1999—2009 after the implementation of the Program, the changes of landscape pattern in Puding County were characterized in dynamic variation of land use area, landscape heterogeneity, landscape structure, and shape transformation. The changes on area of land use and the landscape heterogeneity were the leading factors affecting the changes of landscape pattern of the region; 2) Regarding the variation of area, conversion from farmland and bare land to forestland and grassland was the most prominent, and the area of forestland, grassland and built-up area increased rapidly by 53%,50% and 140%, respectively. At the same time, farmland decreased by 133.32 km2; 3) the number of patches (NP), one of the landscape indices, was confirmed on the rise with the other index mean patch size (MPS) decreasing, and fragmentation of the landscape ecological system was aggravated; 4) Considering landscape heterogeneity, the dominant components were more diverse, the degree of landscape heterogeneity gradually rose, and the overall characteristics of ecological landscape became more regular. Forestland, grassland and construction land were more concentrated, however farmland and bare land were more decentralized. The degree of fragmentation increased somehow. In conclusion, evaluation results provide useful guidelines for the restoration and reconstruction of degraded Karst ecosystem.