Characterization and projection of spatial and temporal changes in habitat quality of Sanjiangyuan based on land use change

Sanjiangyuan is an extremely important biodiversity-conservation area with notable worldwide ecological significance. However, due to global climate change and increased human activities, the natural environment in this region has undergone major alterations. In this work, we used the InVEST model to assess the spatial and temporal distribution of habitat quality and habitat degradation in the Sanjiangyuan region from 2000 to 2020. CA-Markov model was used to predict the land use changes under "natural development" (ND) and "ecological protection" (EP) scenarios from 2025 to 2050, and a comparative analysis of land use and habitat-quality changes was made in combination with the results of ecological zoning planning. We found that changes in human use land and bare land directly affect changes in habitat quality in Sanjiangyuan and are a major threat to habitat quality. Using the human-footprint index, Sanjiangyuan was divided into key protected areas, key restoration areas, and moderately developed areas. We compared the changes in habitat quality under two scenarios and discovered that under the EP scenario, the region of high habitat quality expanded, indicating that the EP scenario is beneficial for the sustainable development and conservation of biodiversity in Sanjiangyuan.