Spatiotemporal Evolution of Ecosystem Services in the Wanhe Watershed Based on Cellular Automata (CA)-Markov and InVEST Models

Abstract

The evaluation of habitat quality and its genesis is of great significance to ecological protection of the watershed. Based on land use data, Digital Elevation Model (DEM), and road network data and population data, the Cellular Automata (CA)-Markov model and InVEST model were used to analyzed the land use change in the Wanhe Watershed, predicting the land use in 2025. Based on this, the degree of the habitat degradation and habitat quality in 2000, 2005, 2010, 2015, 2020, and 2025 were predicted and analyzed, and combined with the particularity of the terrain in the study area, the topography was introduced. Landform relief gradient was used to discuss the relationship between habitat quality and topographic factors in the Wanhe Watershed, and to reveal the distribution law. The result shows that from 2000 to 2025, farmland and forestland are the main land use types in the study area, and the main change is due to the expansion of the construction land, whereby the area increased by 62.86 km2, with an increase of 34.41%, mainly from farmland and forestland. From 2000 to 2020, mainly due to the expansion in urban land and the reduction in forestland, the habitat degradation tends to be serious, and the habitat quality generally shows a downward trend, with areas with low habitat quality having had the largest increase from 452.67 km² in 2000 to 526.15 km² in 2025. The topography of the study area affects the distribution of natural landscapes and the intensity of human activities, resulting in significant differences in the landscape pattern of habitat degradation and habitat quality. The western mountains are relatively better. After 2020, due to the implementation of environmental protection policies, the habitat quality has tended to improve. This study can promote the adjustment of land use planning policies in the study area, maintain the biodiversity in the watershed, and realize the coordinated development of environmental benefits and social and economic development. The research results have theoretical significance and practical value for ecological environmental protection and land use layout in Wanhe Watershed.