Widespread crown condition decline, food web disruption, and amplified tree mortality with increased climate change-type drought
Widespread crown condition decline, food web disruption, and amplified tree mortality with increased climate change-type drought
复制标题
DOI：
10.1073/pnas.1010070108
复制
发表时间：
2011-01-25
影响因子：
11.1
通讯作者：
Penuelas, Josep
中科院分区：
文献类型：
--
作者：
Carnicer, Jofre;Coll, Marta;Penuelas, Josep
气候变化正在逐步增加北方半球的严重干旱事件，造成区域性树木死亡事件，并导致全球森林碳汇效率下降。严重缺乏对森林中干旱引起的宏观生态反应，包括落叶、死亡率和食物网反应的全社区综合评估。在这里，我们报告了1987-2007年期间发生在南欧森林的树冠落叶普遍增加。森林树种一致和显着改变其冠叶结构，在其分布的干燥部分落叶的百分比增加，以应对水分亏缺增加。我们评估了与南欧森林，特别是伊比利亚半岛地区落叶增加的树木的人口响应。我们发现，落叶趋势是由树木死亡率显着增加，在干燥的地区，与树木密度和温度的影响。此外，我们表明，严重的干旱影响与昆虫和真菌落叶动态的突然变化有关，干旱对食物网产生长期的破坏性影响。我们的研究结果揭示了一个复杂的地理马赛克的物种特异性的气候变化驱动的干旱压力的伊比利亚半岛，具有压倒性的主要趋势增加干旱损害。
Climate change is progressively increasing severe drought events in the Northern Hemisphere, causing regional tree die-off events and contributing to the global reduction of the carbon sink efficiency of forests. There is a critical lack of integrated community-wide assessments of drought-induced responses in forests at the macroecological scale, including defoliation, mortality, and food web responses. Here we report a generalized increase in crown defoliation in southern European forests occurring during 1987-2007. Forest tree species have consistently and significantly altered their crown leaf structures, with increased percentages of defoliation in the drier parts of their distributions in response to increased water deficit. We assessed the demographic responses of trees associated with increased defoliation in southern European forests, specifically in the Iberian Peninsula region. We found that defoliation trends are paralleled by significant increases in tree mortality rates in drier areas that are related to tree density and temperature effects. Furthermore, we show that severe drought impacts are associated with sudden changes in insect and fungal defoliation dynamics, creating long-term disruptive effects of drought on food webs. Our results reveal a complex geographical mosaic of species-specific responses to climate change-driven drought pressures on the Iberian Peninsula, with an overwhelmingly predominant trend toward increased drought damage.