Observed divergence in vegetation sensitivity to climate variability across bedrocks in Southwest China based on new...

The vegetation sensitivity to climate variability is an important component of ecosystem response to environmental perturbation. Understanding the vegetation sensitivity and its trends is crucial for the ecosystem management. However, this aspect remains inadequately understood for the Southwest China region with highly eco-fragile karst ecosystems. By employing a latest remote-sensed vegetation index, we examined the vegetation sensitivity index (VSI) of three bedrocks and its temporal trends. The bedrocks were categorized as continuous carbonate region (CCR) (more than 65% carbonate rock) or discontinuous carbonate region (DCR) (15-65% carbonate rock). The results showed that vegetation sensitivity exhibited high spatial heterogeneity during the 1982-2022 growing season. In general, VSI was higher in the Yunnan-Guizhou Plateau and the Hengduan Mountains, indicating that these high-altitude areas are highly sensitive to climate. The DCR region has the largest mean VSI, indicating more sensitive to climate than other bedrocks. Vegetation sensitivity decreased significantly in more than 56% of the area covered by vegetation. The greatest reduction in VSI was observed in DCR areas. Temperature was the primary driver of vegetation sensitivity in CCR regions, while precipitation dominated vegetation in DCR regions. Climate controls on VSI were likewise time-varying. The effect of temperature in the CCR was increasing, while the effect of radiation in karst areas was decreasing. The turning points occurred in the period of 2005-2010, indicating that ecological engineering had a lag effects on vegetation sensitivity reduction. Our findings provide unique insights for practicing site-specific ecological restoration on different bedrock.