School of Biological Sciences, University of Utah, Salt Lake City, UT, USA.
Department of Earth System Science, Stanford University, Stanford, CA, USA.
Nature. 2018 Sep;561(7724):538-541. doi: 10.1038/s41586-018-0539-7. Epub 2018 Sep 19.
Plants influence the atmosphere through fluxes of carbon, water and energy, and can intensify drought through land-atmosphere feedback effects. The diversity of plant functional traits in forests, especially physiological traits related to water (hydraulic) transport, may have a critical role in land-atmosphere feedback, particularly during drought. Here we combine 352 site-years of eddy covariance measurements from 40 forest sites, remote-sensing observations of plant water content and plant functional-trait data to test whether the diversity in plant traits affects the response of the ecosystem to drought. We find evidence that higher hydraulic diversity buffers variation in ecosystem flux during dry periods across temperate and boreal forests. Hydraulic traits were the predominant significant predictors of cross-site patterns in drought response. By contrast, standard leaf and wood traits, such as specific leaf area and wood density, had little explanatory power. Our results demonstrate that diversity in the hydraulic traits of trees mediates ecosystem resilience to drought and is likely to have an important role in future ecosystem-atmosphere feedback effects in a changing climate.
植物通过碳、水和能量的通量来影响大气，并通过陆地-大气反馈效应加剧干旱。森林中植物功能性状的多样性，特别是与水（水力）输送有关的生理性状，在陆地-大气反馈中可能起着关键作用，特别是在干旱期间。在这里，我们结合了 40 个森林站点的 352 个站点年的涡度协方差测量、植物水分含量的遥感观测和植物功能性状数据，以测试植物性状的多样性是否会影响生态系统对干旱的响应。我们有证据表明，较高的水力多样性在温带和北方森林的干旱期缓冲了生态系统通量的变化。水力性状是干旱响应跨站点模式的主要显著预测因子。相比之下，标准的叶片和木材性状，如比叶面积和木材密度，几乎没有解释能力。我们的结果表明，树木水力性状的多样性调节了生态系统对干旱的恢复能力，并且在气候变化下，在未来的生态系统-大气反馈效应中可能发挥重要作用。
