Spatio-temporal evolution and multi-scenario simulation of landscape ecological risk in the Taohe River Basin based on the PLUS model

Xiaodan Li^1*Zhenting Yin²Xiaoning Zhang³Xuelu Liu³

• ¹College of Forestry, School of management，Gansu Agricultural University, Lanzhou, China
• ²School of management，Gansu Agricultural University, Lanzhou, China
• ³College of Resources and Environmental Sciences, School of management，Gansu Agricultural University, Lanzhou, China

Ecological conservation and high-quality development in the Yellow River Basin represent a major national strategy in China. The Taohe River Basin, the second-largest tributary in the upper reaches of the Yellow River Basin, lies at the transition zone between the northeastern edge of the Qinghai-Tibet Plateau and the western edge of the Loess Plateau. To date, no studies have yet been published on landscape ecological risk assessments (LERA) for this watershed based on simulations of future land-use changes. Therefore, this study focuses on the Taohe River Basin as the research area. It systematically analyzes the evolution of landscape patterns and the spatiotemporal distribution characteristics of ecological risks from 2000 to 2020. The patch-generating land use simulation (PLUS) model was employed to predict the spatial distribution patterns and evolution trends of risks under different scenarios up to 2040. The research results indicate that: (1)From 2000 to 2020, forest land and grassland areas accounted for 80% of the basin, with the most significant expansion occurring in construction land (dynamic degree: 3.69%). The area of arable land and unutilized land shrank by 447.78 km2 and 35.65 km2, respectively. (2)Landscape ecological risks exhibited a "high in northeast, low in south pattern". The proportion of low and very low risks increased from 37.87% to 50.74%, while medium and high risks decreased from 62.13% to 49.26%. (3)Land use simulations for the Tao River Basin under different scenarios by 2040 indicate that forest land and grassland remain the dominant landscape types. Under the natural development scenario (NDS), grassland and construction land increase by 141.79 km2 and 56.79 km2, respectively. Under the urban development scenario (UDS), arable land expands by 68.21 km2. Under both the ecological conservation scenarios (ECS) and farmland protection scenarios (FPS), grassland and construction land expansion are significant. (4)Scenario simulations indicate that the ecological conservation scenario (ECS) yields the largest increase in low-risk areas (+463.14 km2) while reducing high-risk areas by 205.58 km2, making it most conducive to mitigating ecological risks and aligning with sustainable development requirements. These findings provide scientific basis for ecological conservation and high-quality development in the Taohe River Basin.