石羊河流域景观生态风险时空分布特征

Temporal and spatial distribution characteristics of landscape ecological risk in the Shiyang River basin

石羊河流域地处干旱内陆河流域,是西北乃至中国重要的生态屏障。以1986、2000和2015年三期土地利用数据为基础,构建景观生态风险评价指数,研究其景观生态风险时空分布特征及其与地形因子之间的关系。结果表明:(1)石羊河流域景观生态风险空间分布呈南低北高的趋势。Ⅰ、Ⅳ、Ⅴ级景观生态风险区域为石羊河流域的主要风险类型。(2)Ⅰ级景观生态风险在较高海拔、中坡度出现的频率高,Ⅱ级景观生态风险在高海拔、中坡度具有优势,Ⅲ级景观生态风险分布优势在高海拔、低坡度,Ⅳ—Ⅴ级景观生态风险均在低海拔、低坡度出现的频率高。(3)Ⅰ—Ⅱ级景观生态风险中土地类型主要为草地和耕地,Ⅲ—Ⅴ级景观生态风险主要土地类型为未利用地。研究结果对流域生态保护和经济社会可持续发展具有重要意义。

The Shiyang River basin is located in the arid inland river basin and is an important ecological barrier in Northwestern China and even China. Based on the three phases of land use data in 1986, 2000, and 2015, a landscape ecological risk assessment index was constructed to study the spatial and temporal distribution characteristics of landscape ecological risk and its relationship with terrain factors. The results show that:(1) The spatial distribution of landscape ecological risk in the Shiyang River basin showed a trend of low in the south and high in the north. Ⅰ, Ⅳ, and Ⅴ landscape ecological risk areas were the main types of risks in the Shiyang River basin.(2) Ⅰ landscape ecological risks had a high frequency at higher altitude and mid-slope, and Ⅱ landscape ecological risks had high-altitude and mid-slope. Advantages,the distribution advantages of grade Ⅲ landscape ecological risk were at high altitude and low slope, and the frequency of grade Ⅳ-Ⅴ landscape ecological risks were high at low altitude and low slope.(3) The land types in the landscape ecological risks of grades Ⅰ-Ⅱ were mainly grassland and cultivated land, and the main land types of landscape ecological risks in grades Ⅲ-Ⅴ were unused land. The research results are of great significance to the ecological protection of the river basin and the sustainable development of the economy and society.