Quantifying within‐species trait variation in space and time reveals limits to trait‐mediated drought response
Quantifying within‐species trait variation in space and time reveals limits to trait‐mediated drought response
复制标题
量化物种内性状在空间和时间上的变化揭示了性状介导的干旱反应的局限性
DOI：
10.1111/1365-2435.14112
复制
发表时间：
2022
影响因子：
5.2
通讯作者：
Anderegg, William R. L.
中科院分区：
文献类型：
--
作者：
Kerr, Kelly L.;Anderegg, Leander D. L.;Zenes, Nicole;Anderegg, William R. L.
气候变化给地球仪上的许多森林带来了压力，但有些树种可能能够通过驯化和适应新的环境条件而生存下来。树木在其一生中通过生理和功能性状的变化来适应环境的能力，这里定义为适应潜力，还不为人所知。我们通过检查干旱响应功能性状在空间和时间上的种内变化，以及性状变化如何影响干旱诱导的树木死亡率，研究了颤抖的白杨和黄松的适应潜力。我们测量了美国西南部科罗拉多成熟树木的木质部张力、形态性状和生理性状，跨越了每个物种的分布范围和3年的气候差异。颤抖的白杨功能性状显示出很高的种内变异，渗透调节和碳同位素辨别力是干旱地区和干旱年份耐旱性提高的关键决定因素。然而，在2018年严重干旱的年份，由于死亡率上升，低海拔的颤抖白杨树被推到了耐旱极限。干旱期间较高的比叶面积与第二年较高的冠层顶枯百分比相关。黄松功能性状表现出较少的种内变异，虽然渗透调节也是提高耐旱性的关键机制。值得注意的是，这两个树种几乎所有性状的年际变化都比海拔变化大。我们的研究结果揭示了种内性状变异的范围和限制，以介导美国西南部主要树种的干旱反应，并将有助于提高我们建模和预测森林对气候变化的反应的能力。
Climate change is stressing many forests around the globe, yet some tree species may be able to persist through acclimation and adaptation to new environmental conditions. The ability of a tree to acclimate during its lifetime through changes in physiology and functional traits, defined here as its acclimation potential, is not well known.We investigated the acclimation potential of trembling aspenPopulus tremuloidesand ponderosa pinePinus ponderosatrees by examining within‐species variation in drought response functional traits across both space and time, and how trait variation influences drought‐induced tree mortality. We measured xylem tension, morphological traits and physiological traits on mature trees in southwestern Colorado, USA across a climate gradient that spanned the distribution limits of each species and 3 years with large differences in climate.Trembling aspen functional traits showed high within‐species variation, and osmotic adjustment and carbon isotope discrimination were key determinants for increased drought tolerance in dry sites and in dry years. However, trembling aspen trees at low elevation were pushed past their drought tolerance limit during the severe 2018 drought year, as elevated mortality occurred. Higher specific leaf area during drought was correlated with higher percentages of canopy dieback the following year. Ponderosa pine functional traits showed less within‐species variation, though osmotic adjustment was also a key mechanism for increased drought tolerance. Remarkably, almost all traits varied more year‐to‐year than across elevation in both species.Our results shed light on the scope and limits of intraspecific trait variation for mediating drought responses in key southwestern US tree species and will help improve our ability to model and predict forest responses to climate change.Read the free Plain Language Summary for this article on the Journal blog.