Large-scale climatic and geophysical controls on the leaf economics spectrum
Large-scale climatic and geophysical controls on the leaf economics spectrum
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DOI：
10.1073/pnas.1604863113
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发表时间：
2016-07-12
影响因子：
11.1
通讯作者：
Vaughn, Nicholas
中科院分区：
文献类型：
--
作者：
Asner, Gregory P.;Knapp, David E.;Vaughn, Nicholas
叶经济谱（LES）理论表明植物在资源获取和储存策略之间存在普遍的权衡，表现为叶片氮（N）和磷（P）、单位面积叶质量（LMA）和光合作用之间的关系。然而，环境条件如何介导LES性状的相互关系，特别是在大的生物圈尺度上，仍然是未知的，因为缺乏空间上明确的数据，这最终限制了我们对生态系统过程的理解，如初级生产力和地球化学循环。据我们所知，我们使用机载成像光谱和地理空间建模来生成LES特征的第一个生物圈地图，这里以7600万公顷的安第斯山脉和亚马逊森林为中心，以评估LES特征及其相互关系的气候和地球物理决定因素。海拔和基质是叶片性状分布的共显性驱动因子。多个额外的气候和地球物理因素是植物性状的次要决定因素。N和LMA之间的反相关性遵循一般LES理论，但地形土壤条件强烈介导，有时，消除这种经典的关系。我们没有发现森林冠层中简单的P-LMA或N-P权衡的证据;相反，我们绘制了对海拔和温度敏感的N-P-LMA相互作用的连续体。我们的研究结果揭示了嵌套的气候和地球物理过滤LES性状及其相互关系，森林生产力和适应快速气候变化的预测具有重要意义。
Leaf economics spectrum (LES) theory suggests a universal trade-off between resource acquisition and storage strategies in plants, expressed in relationships between foliar nitrogen (N) and phosphorus (P), leaf mass per area (LMA), and photosynthesis. However, how environmental conditions mediate LES trait interrelationships, particularly at large biospheric scales, remains unknown because of a lack of spatially explicit data, which ultimately limits our understanding of ecosystem processes, such as primary productivity and biogeochemical cycles. We used airborne imaging spectroscopy and geospatial modeling to generate, to our knowledge, the first biospheric maps of LES traits, here centered on 76 million ha of Andean and Amazonian forest, to assess climatic and geophysical determinants of LES traits and their interrelationships. Elevation and substrate were codominant drivers of leaf trait distributions. Multiple additional climatic and geophysical factors were secondary determinants of plant traits. Anticorrelations between N and LMA followed general LES theory, but topo-edaphic conditions strongly mediated and, at times, eliminated this classic relationship. We found no evidence for simple P-LMA or N-P trade-offs in forest canopies; rather, we mapped a continuum of N-P-LMA interactions that are sensitive to elevation and temperature. Our results reveal nested climatic and geophysical filtering of LES traits and their interrelationships, with important implications for predictions of forest productivity and acclimation to rapid climate change.