2002–2022 SPATIAL-TEMPORAL DYNAMICS OF LAND USE CHANGE IN TIANSHUI CITY AND ITS ECOLOGICAL AND ENVIRONMENTAL IMPACTS

Based on land use data of Tianshui City from 2002 to 2022, this study analyzed the spatiotemporal change trajectory of land use transfer and the ecological environment index by applying land use change dynamics, land transfer matrix, kernel density analysis model, and ecological environment quality index.The results showed that the main land use types in Tianshui City were cultivated land and woodland.Over the past 20 years, the area of construction land and woodland increased, while cultivated land, grassland, and unused land decreased, and water areas remained relatively unchanged.Land use types in Tianshui City changed primarily from cultivated land to woodland, construction land, and grassland.These changes occurred mainly in the urban area and its surroundings, with the highest frequency in the main urban area.Additionally, the service value of cultivated land, grassland, and unused land showed a downward trend, while forest ecological service value showed an upward trend.Furthermore, the land use types providing services include cultivated land, grassland, and woodland, with woodland and grassland being the main types providing regulating and supporting services.