Ecosystem service value change analysis of Chishui River Basin based on land use change

Based on the remote sensing interpreted land use data of Chishui River basin in 1990, 1999, 2010 and 2018, the localization-corrected equivalent factor method and GIS spatial analysis techniques were used to analyze the land use change characteristics, the ecosystem services value (ESV) change characteristics and the effects of land use change on the change of ESV. The results showed that the area of cultivated land, grassland and unused land decreased, and the area of construction land, forest land and water increased from 1990 to 2018. The land use transfer was mainly reflected in the mutual flow between cultivated land-forest-grassland and the encroachment of construction land on cultivated land and grassland. From 1990 to 2018, ESV increased from 41.190 billion yuan to 41.354 billion yuan in Chishui River basin, forest land was the main contributing part of ESV, and the increase of water area was the main influencing factor of the increase of ESV. The spatial distribution of ESV showed the characteristics of "high in the middle reaches, low in the upper and lower reaches", and the distribution of high value areas overlapped highly with that of forest land. The continuous expansion of urban construction land caused a decrease in ESV, and forest land and watershed, and cropland and grassland contributed positively and negatively to ESV due to area changes, respectively. The implementation of policies such as the change of population structure between rural and urban areas, the return of farmland to forest and watershed ecological management had promoted an increase to ESV.