Asymmetric root distributions reveal press–pulse responses in retreating coastal forests
Asymmetric root distributions reveal press–pulse responses in retreating coastal forests
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不对称的根分布揭示了退缩的沿海森林的压力脉冲响应
DOI：
10.1002/ecy.3468
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发表时间：
2021
期刊：
影响因子：
4.8
通讯作者：
Kirwan, Matthew L.
中科院分区：
文献类型：
--
作者：
Messerschmidt, Tyler C.;Langston, Amy K.;Kirwan, Matthew L.
气候变化对生态系统的影响表现在生物体如何应对偶发和持续的压力。沿海森林向盐沼的转变是生态系统状态变化的一个突出例子，这是由海平面上升（press）和偶发风暴（pulse）的持续压力驱动的。在这里，我们测量了生根尺寸和下降方向的143风东红雪松（Juniperus virginiana）树木在迅速撤退的沿海森林在切萨皮克湾（美国）。我们发现，树木的根系分布不对称远离土壤盐渍化的前沿和淡水来源。根的长度、数量和周长在上坡方向上始终高于下坡方向，表明对海平面上升和盐度胁迫的积极形态适应。被风吹倒的树木一致地落在上坡方向，无论方面和盛行风向，这表明不对称的生根不稳定的站立的树木，并降低了他们的能力，承受大风。总之，这些观察结果有助于解释沿海森林恢复力的奇怪观察，并强调了一个有趣的非加性响应气候变化，适应压力压力增加了对脉冲压力的脆弱性。
The impacts of climate change on ecosystems are manifested in how organisms respond to episodic and continuous stressors. The conversion of coastal forests to salt marshes represents a prominent example of ecosystem state change, driven by the continuous stress of sea‐level rise (press), and episodic storms (pulse). Here, we measured the rooting dimension and fall direction of 143 windthrown eastern red cedar (Juniperus virginiana) trees in a rapidly retreating coastal forest in Chesapeake Bay (USA). We found that tree roots were distributed asymmetrically away from the leading edge of soil salinization and towards freshwater sources. The length, number, and circumference of roots were consistently higher in the upslope direction than downslope direction, suggesting an active morphological adaptation to sea‐level rise and salinity stress. Windthrown trees consistently fell in the upslope direction regardless of aspect and prevailing wind direction, suggesting that asymmetric rooting destabilized standing trees, and reduced their ability to withstand high winds. Together, these observations help explain curious observations of coastal forest resilience, and highlight an interesting nonadditive response to climate change, where adaptation to press stressors increases vulnerability to pulse stressors.