[Spatiotemporal Changes of Land Use and Their Impacts on Ecosystem Service Value in the Agro-pastoral Ecotone of Northern China].

Using the geographic information graph method to analyze the spatiotemporal changes of land use/land cover change （LUCC） in the agro-pastoral ecotone of northern China from 2000 to 2020, the ecosystem service value （ESV） in the study area was calculated based on an improved equivalent factor method, and the response degree between LUCC and ESV change was explored. The results showed that the main land use types in the agro-pastoral ecotone of northern China were grassland and cultivated land. The land use change rate from 2000 to 2020 was 0.59%. After 2010, the land use change rate decreased, and construction land was the most significant land use type in the study area. The most obvious change in the land use transfer map in the study area was the "cultivated land → grassland" map type, followed by the "grassland → cultivated land" map type. In the land use increase map of the research area from 2000 to 2020, the newly added grassland area was the largest, followed by newly added cultivated land. In the land use decrease map, the shrinking cultivated land area was the largest, followed by shrinking grassland. The overall spatial pattern of ESV in the agro-pastoral ecotone of northern China showed a characteristic of "high in the central region and low in the east-west region," showing an increasing trend, mainly manifested as a general increase. The conversion of cultivated land to grassland and forest land, as well as the conversion of grassland to forest land, were the main driving forces for the increase in ESV in the agro-pastoral ecotone of northern China. The conversion of grassland to cultivated land and water to cultivated land was the main driving force for the decrease in ESV in the study area. The research results reveal the characteristics of land use change in the agro-pastoral ecotone of northern China, clarify the impact of different types of land use transformation on the value of ecosystem services, and provide scientific basis for optimizing regional land use structure and spatial pattern and enhancing ecosystem services.