Microclimate moderates plant responses to macroclimate warming
Microclimate moderates plant responses to macroclimate warming
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DOI：
10.1073/pnas.1311190110
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发表时间：
2013-11-12
影响因子：
11.1
通讯作者：
Verheyen, Kris
中科院分区：
文献类型：
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作者：
De Frenne, Pieter;Rodriguez-Sanchez, Francisco;Verheyen, Kris
最近的全球变暖正在影响海洋、淡水和陆地生态系统，有利于适应温暖条件的物种和/或减少适应寒冷的生物体的数量（即群落的“嗜热化”）。然而，据报道，一些类群和地区对气温升高缺乏社区反应，这表明“气候滞后”可能很频繁。在这里，我们表明，森林冠层关闭带来的小气候效应可以缓冲生物对大气候变暖的反应，从而解释了明显的气候滞后。使用来自欧洲和北美温带森林 1,409 个植被样地的数据（每个样地在 12-67 年的时间间隔内至少进行两次调查），我们记录了地面植物群落的显着嗜热化。这些变化反映了适应较冷条件的物种同时减少和适应较温暖条件的物种增加。然而，嗜热作用，特别是适应温暖的物种的增加，在树冠变得更密集的森林中减弱，这可能通过增加遮荫反映了较凉爽的生长季节地面温度。近几十年来，随着许多温带森林的立木蓄积量增加，当地的小气候效应通常可能会减轻宏观气候变暖对森林林下植被的影响。相反，增加木质生物质的采伐（例如用于生物能源）可能会打开森林树冠并加速温带森林生物多样性的嗜热化。
Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., "thermophilization" of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that "climatic lags" may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass-e.g., for bioenergy-may open forest canopies and accelerate thermophilization of temperate forest biodiversity.