Environmental context explains Levy and Brownian movement patterns of marine predators
Environmental context explains Levy and Brownian movement patterns of marine predators
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DOI：
10.1038/nature09116
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发表时间：
2010-06-24
期刊：
影响因子：
64.8
通讯作者：
Sims, David W.
中科院分区：
文献类型：
--
作者：
Humphries, Nicolas E.;Queiroz, Nuno;Sims, David W.
最优搜索理论，即所谓的利维飞行觅食假说（1），预测捕食者应该采用被称为利维飞行的搜索策略，其中猎物稀疏且分布不可预测，但布朗运动足以有效地定位丰富的猎物（2-4）。实证研究产生了争议，因为用于识别Levy行为的统计方法的准确性最近受到质疑（5，6）。因此，觅食动物是否在野外表现出利维飞行仍不清楚。此外，至关重要的是，尚未测试在具有不同预期资源分布的自然景观中观察到的运动模式是否符合该理论的中心预测。在这里，我们使用最大似然方法来测试利维模式与环境梯度在最大的动物运动数据集为此目的组装。在14种公海掠食性鱼类（鲨鱼，金枪鱼，长嘴鱼和海洋太阳鱼）中发现了强烈的支持Levy搜索模式，其中一些人在Levy和布朗运动之间切换，因为他们穿越不同的栖息地类型。我们测试了这两个主要模式的空间发生，并发现利维行为与生产力较低的沃茨（稀疏的猎物）和布朗运动与生产货架或收敛前的栖息地（丰富的猎物）。这些结果与Levy飞行觅食假说（1，7）一致，支持生物搜索策略自然进化的方式，他们利用最佳Levy模式的论点（8，9）。
An optimal search theory, the so-called Levy-flight foraging hypothesis(1), predicts that predators should adopt search strategies known as Levy flights where prey is sparse and distributed unpredictably, but that Brownian movement is sufficiently efficient for locating abundant prey(2-4). Empirical studies have generated controversy because the accuracy of statistical methods that have been used to identify Levy behaviour has recently been questioned(5,6). Consequently, whether foragers exhibit Levy flights in the wild remains unclear. Crucially, moreover, it has not been tested whether observed movement patterns across natural landscapes having different expected resource distributions conform to the theory's central predictions. Here we use maximum-likelihood methods to test for Levy patterns in relation to environmental gradients in the largest animal movement data set assembled for this purpose. Strong support was found for Levy search patterns across 14 species of open-ocean predatory fish (sharks, tuna, billfish and ocean sunfish), with some individuals switching between Levy and Brownian movement as they traversed different habitat types. We tested the spatial occurrence of these two principal patterns and found Levy behaviour to be associated with less productive waters (sparser prey) and Brownian movements to be associated with productive shelf or convergence-front habitats (abundant prey). These results are consistent with the Levy-flight foraging hypothesis(1,7), supporting the contention(8,9) that organism search strategies naturally evolved in such a way that they exploit optimal Levy patterns.