Widespread drought-induced tree mortality at dry range edges indicates that climate stress exceeds species' compensating mechanisms
Widespread drought-induced tree mortality at dry range edges indicates that climate stress exceeds species' compensating mechanisms
复制标题
干旱引起的干旱区边缘树木大面积死亡表明，气候压力超过了物种的补偿机制
DOI：
10.1111/gcb.14771
复制
发表时间：
2019-08-13
影响因子：
11.6
通讯作者：
Trugman, Anna T.
中科院分区：
文献类型：
--
作者：
Anderegg, William R. L.;Anderegg, Leander D. L.;Trugman, Anna T.
干旱导致的树木死亡率预计将因气候变化而增加，这将产生多方面的生态和社会影响，包括可能削弱或逆转陆地碳汇。树木死亡率的预测仍然有限，在很大程度上是因为种内的变化，由于可塑性或适应性和生态系统的调整，可以缓冲死亡率在干旱地区。在这里，我们对全球超过100种木本植物的50项研究进行了荟萃分析，以量化物种内种群对干旱死亡率的脆弱性以及功能性状或气候是否介导死亡率模式。我们发现，死亡率主要发生在干燥的人口，这种模式是更明显的木质部的物种，可以容忍高度负水势，通常被认为是一种适应性特征的干旱地区，和物种的经验，在水分胁迫的变化更高。我们的研究结果表明，气候压力已经超过生理和生态系统水平的容忍度或补偿机制，在干旱区边缘触发广泛的死亡率，并提供了一个基础，为未来的死亡率预测经验分布和机械植被模型。
Drought-induced tree mortality is projected to increase due to climate change, which will have manifold ecological and societal impacts including the potential to weaken or reverse the terrestrial carbon sink. Predictions of tree mortality remain limited, in large part because within-species variations in ecophysiology due to plasticity or adaptation and ecosystem adjustments could buffer mortality in dry locations. Here, we conduct a meta-analysis of 50 studies spanning >100 woody plant species globally to quantify how populations within species vary in vulnerability to drought mortality and whether functional traits or climate mediate mortality patterns. We find that mortality predominantly occurs in drier populations and this pattern is more pronounced in species with xylem that can tolerate highly negative water potentials, typically considered to be an adaptive trait for dry regions, and species that experience higher variability in water stress. Our results indicate that climate stress has exceeded physiological and ecosystem-level tolerance or compensating mechanisms by triggering extensive mortality at dry range edges and provides a foundation for future mortality projections in empirical distribution and mechanistic vegetation models.