Why large-scale climate indices seem to predict ecological processes better than local weather
Why large-scale climate indices seem to predict ecological processes better than local weather
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DOI：
10.1038/nature02708
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发表时间：
2004-07-01
期刊：
影响因子：
64.8
通讯作者：
Grenfell, BT
中科院分区：
文献类型：
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作者：
Hallett, TB;Coulson, T;Grenfell, BT
北大西洋涛动(1)等大尺度气候指数与许多物种的种群动态(2)、人口比率变化(3)和表型性状值（4,5）有关。矛盾的是，这些大尺度指数似乎比当地气候更能预测生态过程（5-8）。利用来自Soay羊种群的详细数据（9,10），我们表明，在3个月期间的任何时间，强降雨、大风或低温都可能立即或延迟几天导致死亡。生态学家使用的大多数当地气候测量都无法捕捉天气和生态过程之间的复杂联系，这可能有助于解释为什么跨越几个月的大规模季节性气候指数可以优于当地气候因素。此外，我们展示了为什么理解气候影响种群生态的机制是重要的。通过模拟，我们证明了在死亡周期内恶劣天气的时间可以对物种间的食物竞争产生重要的调节影响，揭示了气候和密度依赖之间的相互作用（11），使用大规模气候指数或不适当的当地天气变量可能会掩盖这一点。
Large-scale climatic indices such as the North Atlantic Oscillation(1) are associated with population dynamics(2), variation in demographic rates(3) and values of phenotypic traits(4,5) in many species. Paradoxically, these large-scale indices can seem to be better predictors of ecological processes than local climate(5-8). Using detailed data from a population of Soay sheep(9,10), we show that high rainfall, high winds or low temperatures at any time during a 3-month period can cause mortality either immediately or lagged by a few days. Most measures of local climate used by ecologists fail to capture such complex associations between weather and ecological process, and this may help to explain why large-scale, seasonal indices of climate spanning several months can outperform local climatic factors. Furthermore, we show why an understanding of the mechanism by which climate influences population ecology is important. Through simulation we demonstrate that the timing of bad weather within a period of mortality can have an important modifying influence on intra-specific competition for food, revealing an interaction between climate and density dependence(11) that the use of large-scale climatic indices or inappropriate local weather variables might obscure.