南水北调中线水源区景观格局演变及生态风险评估

Landscape pattern evolution and ecological risk assessment in water source region of middle route of South-to-North water diversion project

南水北调中线工程水源区位于地理单元过渡带和生态敏感区,其生态环境变化直接影响水量与水质.水源区生态景观格局变化和生态风险评估研究,对南水北调中线工程健康发展有重要理论与实践意义.根据水源区1990年、2005年、2020年三期土地利用数据,分析了景观格局及生态风险时空分布特征.研究发现:地貌和气候是地理单元过渡带和生态敏感区的景观格局的本底.水源区林地和草地是主要景观,也是优势景观,这是由地貌和气候所决定的.耕地斑块形状最复杂,林地的结合度和聚集度最大.地理单元过渡带和生态敏感区在短时间尺度上的生态景观格局变化主要影响因素是人类活动区的分布及活动强度.南水北调中线水源区景观生态风险逐年降低,高风险区不断减少,中风险区仍然在区域中占主体.景观生态风险在空间上呈西高东低趋势.

The middle route of the South-to-North Water Diversion Project is located in the transition zone of geographical units and ecologically sensitive area.The changes of ecological environment would directly affect the water quantity and quality of the project.Based on the land use data of the water source area of the middle route of South-to-North Water Diversion Project in 1990,2005 and 2020,the spatial and temporal distribution characteristics of landscape pattern and ecological risk were analyzed.It showed that geomorphology and climate are the framework of landscape pattern in transitional zone and ecologically sensitive area.Woodland and grassland were still the main landscape and the dominant landscape types,it depends on the landscape and climate.The shape of cultivated land patches were the most complex,and the integration degree and aggregation degree of woodland were the largest types.The distribution and intensity of human activities are the main factors affecting the change of landscape pattern in transitional zone and ecologically sensitive area in small and medium time scales.In the water source area of the middle route of the South-to-North Water Transfer project,the ecological risk is decreased year by year.The number of high risk areas decreased a lot,and the middle risk areas are still the largest areas.The ecological risk is higher in the west and lower in the east.