How to cope with drought and not die trying: drought acclimation across tree species with contrasting niche breadth

Worldwide drought events have been reported to cause tree growth decline and mortality, thus altering the carbon (C) balance of forest ecosystems. While most of the attention has been focused on the physiological mechanisms associated with drought-induced tree responses of a few species at specific locations, the ecological attributes of these species, like their niche breadth, may be also important in determining species’ sensitivity or resilience to drought. We postulated that wide-niche breadth tree species should be more drought-resilient than narrow-niche breadth species. 2. Using the most severe 2015-2016 El Niño drought event in the last 70 years in Patagonia, we determined pre- and post-drought growth (BAI, basal area increment), C reserves in the form of non-structural carbohydrates (NSCs = starch and soluble sugars), wood isotope (δ13C, iWUE and δ18O) signaling, and xylem anatomy (mean vessel diameter, mvd) in eight angiosperm tree species of contrasting niche breadth across a...

据报道，全球范围内的干旱事件已引发树木生长衰退与死亡，进而改变森林生态系统的碳（carbon, C）平衡。当前多数研究聚焦于特定区域内少数物种受干旱诱导的生理响应机制，但这些物种的生态属性——如其生态位幅——在决定物种对干旱的敏感性或恢复力方面同样可能至关重要。我们提出如下假说：生态位幅较宽的树木物种，其干旱恢复力应优于生态位幅较窄的物种。
2. 本研究依托巴塔哥尼亚地区过去70年间最为严重的2015-2016年厄尔尼诺（El Niño）干旱事件，针对8个生态位幅存在显著差异的被子植物树种，测定了干旱前后的生长指标（茎干横断面积增量，basal area increment, BAI）、以非结构性碳水化合物（non-structural carbohydrates, NSCs = 淀粉与可溶性糖）形式存在的碳储备、木质部同位素信号（δ¹³C、内在水分利用效率（intrinsic water use efficiency, iWUE）与δ¹⁸O），以及木质部解剖结构指标（平均导管直径，mean vessel diameter, mvd），相关测定横跨……