Mechanisms of a coniferous woodland persistence under drought and heat
Mechanisms of a coniferous woodland persistence under drought and heat
复制标题
DOI：
10.1088/1748-9326/ab0921
复制
发表时间：
2019-04-01
影响因子：
6.7
通讯作者：
Xu, Chonggang
中科院分区：
文献类型：
--
作者：
McDowell, Nate G.;Grossiord, Charlotte;Xu, Chonggang
越来越多的人预测，变暖的干旱会导致森林死亡率上升，但很少有研究调查森林持久性的机制。为了研究森林对温暖干旱的抗性，我们在一个成熟的毛松-单种松孤立林分进行了5年的降水减少（类似于45%的减少）、加热（高于环境温度+4℃）和干旱和热联合实验。尽管实验中出现了严重的干旱和高温，但没有树木死亡，我们只观察到少量的水力衰竭或碳饥饿的证据。两种促进生存的机制得到了支持。首先，获得基岩水或“水力避难所”有助于树木抵抗实验条件。其次，这片林分被隔离在一片死树的景观中，这就阻止了ipusus的入侵，ipusus通常是pinon的最终生物致死因子。这些结合了非生物和生物景观尺度的过程可以通过使树木避免水力衰竭、碳饥饿和暴露于非生物攻击剂来缓和未来干旱对树木死亡率的影响。
Predictions of warmer droughts causing increasing forest mortality are becoming abundant, yet few studies have investigated the mechanisms of forest persistence. To examine the resistance of forests to warmer droughts, we used a five-year precipitation reduction (similar to 45% removal), heat (+4 degrees C above ambient) and combined drought and heat experiment in an isolated stand of mature Pinus edulis-Juniperus monosperma. Despite severe experimental drought and heating, no trees died, and we observed only minor evidence of hydraulic failure or carbon starvation. Two mechanisms promoting survival were supported. First, access to bedrock water, or 'hydraulic refugia' aided trees in their resistance to the experimental conditions. Second, the isolation of this stand amongst a landscape of dead trees precluded ingress by Ips confusus, frequently the ultimate biotic mortality agent of pinon. These combined abiotic and biotic landscape-scale processes can moderate the impacts of future droughts on tree mortality by enabling tree avoidance of hydraulic failure, carbon starvation, and exposure to attacking abiotic agents.