热带森林的干旱死亡是由水力系统引发的,
L Rowland1, A C L da Costa2, D R Galbraith3
1School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
Nature
|November 24, 2015
概括
热带雨林面临干旱死亡, 大型树木在长期干旱后最容易受到水力故障的影响, 表明水运输问题引发树木死亡.
科学领域:
- 生态学
- 森林科学
- 气候变化生物学
背景情况:
- 干旱对热带雨林构成重大威胁,
- 在干旱条件下导致树木死亡的确切机制,特别是碳饥饿和水力故障的作用,尚未完全理解.
研究的目的:
- 调查是否碳饥饿或水力恶化是干旱热带雨林树木死亡的主要原因.
- 分析实验性干旱对树木非结构性碳水化合物 (NSC) 储量和水力功能的长期影响.
主要方法:
- 在巴西亚马逊热带雨林中使用最长时间的干旱实验数据.
- 在实验干旱和对照地块之间比较NSC度和树木死亡率.
- 评估水力损坏和树木大小是影响死亡风险的因素.
主要成果:
- 经过十多年的土壤湿度降低后,干旱森林中因树木死亡而出现显著的生物质损失.
- 与较小的树木相比,较大的树木表现出较高的液压恶化和死亡风险.
- 没有发现碳饥饿的证据;NSC度保持相似,干旱树木的生长率没有下降.
结论:
- 干旱造成的树木死亡的主要原因是水力系统的故障, 而不是碳排放不足.
- 长期干旱对大树造成不成比例的影响,
- 在干旱条件下保持水路运输对于树木生存至关重要.
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