Low growth resilience to drought is related to future mortality risk in trees

First author: Lucía DeSoto; Affiliations: Estación Experimental de Zonas áridas, CSIC (EEZA-CSIC): Almería, Spain

Corresponding author: Lucía DeSoto

Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions may be crucial to long-term survival. We assessed how growth resilience to severe droughts, including its components resistance and recovery, is related to the ability to survive future droughts by using a tree-ring database of surviving and now-dead trees from 118 sites (22 species, >3,500 trees). We found that, across the variety of regions and species sampled, trees that died during water shortages were less resilient to previous non-lethal droughts, relative to coexisting surviving trees of the same species. In angiosperms, drought-related mortality risk is associated with lower resistance (low capacity to reduce impact of the initial drought), while it is related to reduced recovery (low capacity to attain pre-drought growth rates) in gymnosperms. The different resilience strategies in these two taxonomic groups open new avenues to improve our understanding and prediction of drought-induced mortality.

严重的干旱会降低森林的生产力，同时也会诱导树木的死亡。大多数的树木在其一生过程中总要面临几次严重的干旱事件，因此对于干旱环境的生长弹性可能对于树木的长期生存至关重要。作者基于118个地点包含22个物种，超过3500颗树木，通过现在仍然存活树木和目前已经死亡树木的年轮数据库评估了林木生长在经历严重干旱后的弹性状况，包括树木组分对于干旱的抗性以及未来面对干旱条件能够存活的能力。作者发现，在不同地区或不同的取样物种中，同一物种内，相对于那些生长在一起、目前在存活的树木，在缺水时期死亡的树木对于先前非致死性的干旱抗性更弱。在被子植物中，干旱相关的死亡风险与更低的干旱抗性相关，即干旱发生时不能有效降低干旱所带来的负面影响；而在裸子植物中，干旱相关的死亡风险却与更低的干旱后恢复能力相关，即干旱后再难恢复到干旱前的生长速率。本文的研究揭示了两种分类学上完全不同的种子植物，即被子植物与裸子植物，采用了完全不同的抗干旱生长弹性策略，这有助于加深我们对于这一问题的理解，同时也可以提升我们对于干旱诱导型死亡的预测。

通讯：Lucía DeSoto (https://luciadesoto.wordpress.com)

个人简介：2002年，奥维耶多大学，学士、硕士；2010年，巴利亚多利德大学，博士；2010-2016年，科英布拉大学，博士后。

研究方向：不同因素驱动下的植物生长，例如生殖成本、气候条件、种群动态以及其它驱动植物生长的生态压力。

doi: https://doi.org/10.1038/s41467-020-14300-5

Journal: Nature Communications

Published date: January 28, 2020