基于地理探测器模型的疏勒河流域景观生态风险评价及驱动因素分析

Landscape ecological risk assessment and driving factors of the Shule River Basin based on the geographic detector model

疏勒河流域地处河西走廊最西端,是典型的干旱内陆河流域,生态环境极其脆弱,也是我国重要的生态屏障之一。借助Fragstats软件从斑块和景观2个尺度,结合2000—2018年土地利用数据,评价分析疏勒河流域景观生态风险时空变化特征,利用地理探测器定量分析了该流域景观生态风险驱动因素。结果表明:(1)疏勒河流域主要景观类型为未利用地和草地,其斑块个数(NP)、景观形状指数(LSI)、最大斑块指数(LPI)和聚集度指数(AI)值均较高;2000—2018年蔓延度指数(CONTAG)值下降、香农多样性指数(SHDI)和香农均匀度指数(SHEI)值缓慢上升,流域景观破碎度严重。(2)疏勒河流域景观生态风险空间分布呈现北高南低,2000—2018年呈现流域景观生态风险逐渐下降趋势,其中较高风险和高风险地区面积下降明显。(3)人为干扰度是影响景观生态风险空间分布的主要因子,归一化植被指数(NDVI)次之,人口密度影响最小;景观生态风险的影响均为双因子增强或非线性增强,无显著差异大多表现在自然和自然因子间,自然和人为因子之间存在显著性差异。因此,对流域进行景观生态风险指数评价和驱动因素分析至关重要。

The Shule River Basin is a typical arid inland river basin with an extremely fragile ecological environment. It is also one of the most important ecological barriers of northwest China. This study analyzes the spatial and temporal variation characteristics of the landscape ecological risk in the Shule River Basin with land use data from 2000 to 2018 using Fragstats software. First, the results show that the main landscape types in the Shule River Basin are unused land and grassland with high number of patches (NP), landscape shape index (LSI), largest patch index (LPI), and aggregation index (AI) values. The contagion (CONTAG) value dramatically declined, while the Shannon’s diversity index (SHDI) and Shannon’s evenness index (SHEI) values slowly increased during the period from 2000 to 2018. This indicates that the landscape fragmentation is serious in the basin. Second, the landscape ecological risk in the Shule River Basin in the north was higher than that in the south, and a gradual downward trend was observed from 2000 to 2018, especially for the high-risk area. Third, human disturbance is the main factor affecting the spatial distribution of the landscape ecological risk, followed by NDVI and population density. The impact of the landscape ecological risk was double factor or nonlinear enhancement. No significant differences were found between natural and natural factors, while significant differences were determined between natural and anthropogenic factors.