COLLABORATIVE: US-GLOBEC NEP PHASE IIIA-CCS: SCALE-DEPENDENT DYNAMICS OF TOP-TROPHIC PREDATORS AND PREY - TOWARD PREDICTING PREDATOR RESPONSE TO CLIMATE CHANGE

顶层捕食者在构建群落和影响陆架系统中碳流动方面的生态作用是显著的。什么是不太好理解的是如何在中尺度强迫的空间和时间变化影响跨货架和沿货架结构的中营养群落和碳从浮游动物和鱼类转移到顶级捕食者。 调查人员将研究中尺度和更细尺度的空间和时间之间的关系，顶级捕食者（海洋哺乳动物，海鸟），他们的猎物和物理-生物过程中的北方加利福尼亚当前系统（CCS）的数据集收集在多船GLOBEC NEP的努力，调查水域俄勒冈州和北方加州在2000年和2002年。 由于气候在时间尺度上的变异性，从日（上升流）到年际（ENSO）再到十年（太平洋十年涛动），CCS生产力的变异性非常大。 虽然这些趋势可以从大尺度的角度最好地看到，但从中尺度或更细尺度的角度来看，捕食者正在利用可获得的猎物。 将检验两个主要的零假设：1）中尺度强迫，改变沿岸涌升锋和向赤道急流，但不影响顶部捕食者的跨陆架和沿陆架密度和群落结构; 2）通过空间自相关测量的浮游生物和游泳生物分布的空间尺度，处处与物理参数的尺度相当;反过来，食草动物或食鱼动物分布的空间尺度分别与浮游生物和鱼类分布的尺度相当。研究人员将根据2000年的数据建立一个影响顶级捕食者分布的因素的预测模型，并将使用2002年的数据对其进行测试。他们还将使用一般的加法模型估计捕食者的丰度和分布，并构建一个碳流模型，以估计高营养级的碳排放、呼吸和固存（以及迁移者的碳清除）。几种建模方法将被用来确定猎物对应或消耗在一系列尺度的幅度和意义。 空间异质性将在两个层次的生态系统：密度或斑块大小的猎物相对于物理海洋学特征和捕食者的密度相对于他们的猎物。 本文提出的合成提供了一个有价值的基线，在本世纪的早期，在北方CCS的顶部捕食者响应的几个尺度和来源的变化。此外，综合前进的长期发展的预测生物物理模型的发生模式的顶部捕食者（其中许多是濒危物种）在CCS。这些模型的发展将有助于资源管理和人类活动的规划（例如，主要渔业，5个海洋保护区，运输和商业）在北方加州目前的生态系统关闭美国西海岸。

The ecological roles of top predators in structuring communities and affecting the flow of carbon in shelf systems are known to be significant. What is less well understood is how the spatial and temporal variability in mesoscale forcing influences cross-shelf and along-shelf structure of mid-trophic communities and the transfer of carbon from zooplankton and fish to top predators. The investigators will examine mesoscale and finer-scale spatial and temporal relationships between top predators (marine mammals, seabirds), their prey and physical-biological processes in the northern California Current System (CCS) with data sets collected during the multi-ship GLOBEC NEP effort that surveyed waters off Oregon and northern California in 2000 and 2002. Variability in the productivity of the CCS is notably large owing to climate variability on time scales ranging from days (upwelling) to interannual (ENSO) to decadal (Pacific Decadal Oscillation, PDO). While these trends can be best seen from a large-scale view, it is at the mesoscale or finer-scale perspective that predators are exploiting the patches of prey that become available. Two major null hypotheses will be tested: 1) mesoscale forcing, that alters the alongshore upwelling front and equatorward jet, does not affect the cross-shelf and along-shelf density and community structure of top predators; and 2) the spatial scale of plankton and nekton distribution, measured by spatial autocorrelation, is everywhere comparable to that of physical parameters; in turn, the spatial scale of planktivore or piscivore distributions is comparable to the scale of plankton and fish distributions, respectively. The investigators will construct a predictive model of factors affecting top-predator distribution based on 2000 data and will test it using 2002 data. They will also estimate predator abundance and distribution using general additive models and construct a carbon flow model to estimate carbon egested, respired and sequestered by upper trophic levels (as well as carbon removed by migrants). Several modeling approaches will be used to determine the magnitude and significance of prey correspondence or depletion at a range of scales. Spatial heterogeneity will be examined at two levels of the ecosystem: the density or patch size of prey relative to physical oceanographic features and the density of predators relative to their prey. The syntheses proposed herein provide a valuable baseline, for the early part of this century, on top predator response to several scales and sources of variability in the northern CCS. In addition, the synthesis forwards the longer-term development of predictive biophysical models of occurrence patterns of top-predators (many of which are endangered species) in the CCS. Evolution of such models will assist with resource management and planning of human activities (e.g., major fisheries, 5 marine sanctuaries, transportation and commerce) in the northern California Current ecosystem off the west coast of the U.S.