Temporal and spatial changes of ecosystem service value in Loess Hilly-gully region based on land use change

As an important part of the ecosystem of the Loess Plateau, it is of great significance to study the land use change and ecosystem service value in the hilly and gully region of the Loess Plateau for maintaining regional ecological security. Taking Qingyang City, Gansu Province as an example, based on the Landsat remote sensing satellite image data from 1990 to 2020, the land use correlation analysis and ecosystem service value equivalent factor estimation methods were used to analyze the spatio-temporal evolution characteristics of land use and ecosystem service value changes in Qingyang City. The results show that: (1) In the past 30 years, the land use type of Qingyang City gradually formed a pattern of arable land, woodland, grassland, construction land and other continental types accounted for a relatively balanced proportion; (2) In the past 30 years, the cultivated land area of Qingyang City has decreased significantly, with a range of 4.83%, and it is mainly changed into forest land, grassland and construction land; Among them, the degree of comprehensive land use dynamics in 2010 was 0.3%, the highest in four years, mainly due to the implementation of the policy of returning farmland to forest (grass); (3) In the past 30 years, the ecosystem service value of Qingyang City has increased, reaching 987 million yuan, an increase of 5.33%; In 2020, the ecosystem service value of grassland is the largest, reaching 127.257 billion yuan. Climate regulation is the most important ecological service function, accounting for 26% of the total ESV. In general, the restoration and protection of forest and grass plays an important role in maintaining the ecosystem service function of Qingyang City.