黄土高原地区生态脆弱性时空变化及其驱动因子分析

黄土高原是我国生态系统最脆弱的地区之一,科学评估其生态脆弱性是制定有效环境保护和管理措施的前提.然而,过去研究多关注某一小区域的生态脆弱性,不能反映该地区生态脆弱性的整体特征.基于"暴露-敏感性-适应力"模型框架,结合层次分析、空间主成分分析和地理探测器等方法评估了黄土高原地区2000~2015年生态脆弱性的时空变化特征及其驱动因子.结果表明,黄土高原地区生态脆弱性整体较高,并呈现出从东南到西北递增的趋势,且不同土地利用类型脆弱性差异大;2000~2015年生态脆弱性呈先增后降趋势,整体呈微弱降低趋势,其中约64%地区的脆弱性发生了变化;植被覆盖度和降水是控制生态脆弱性时空变化的主要因子,且所有指标因子间均存在明显的交互作用.说明气候变化和人类活动可能有助于降低黄土高原地区的生态脆弱性,但其作用有限.

Spatial-temporal Variations and Their Driving Forces of the Ecological Vulnerability in the Loess Plateau

The Loess Plateau is one of the most eco-fragile regions in China, and therefore the scientific evaluation of its ecological vulnerability provides a premise for the effective implication of ecological protection and management practices. However, previous studies have mainly focused on the ecological vulnerability in a small region, which cannot reflect the overall picture of the ecological vulnerability in the Loess Plateau. Based on the "exposure-sensitivity-adaptation" framework, this study investigated the spatial-temporal patterns and their driving forces of the ecological vulnerability in the Loess Plateau from 2000 to 2015 through a combined use of the analytic hierarchy process, spatial principal component analysis, and Geodetector analysis. The results showed that the ecological vulnerability was overall at a moderate to high level, and the vulnerability was clearly higher in the northwestern part of the Loess Plateau than that in the southeastern counterparts. Additionally, the ecological vulnerability differed greatly by land use type. The ecological vulnerability decreased after an increase from 2000 to 2015 and in general decreased slightly throughout the study period. Therein, approximately 64% of the total land area experienced an upward or downward trend in the vulnerability. Vegetation coverage and precipitation were the two main factors contributing to the spatial-temporal variability in the ecological vulnerability, and there were significant interactions among all the used indicators. This study suggests that climate change and human activities may help reduce the ecological vulnerability over the Loess Plateau, although their contributions are limited.