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.
Keywords: Geodetector; Loess Plateau; ecological vulnerability; spatial principal component analysis; spatial-temporal variations.