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

众所周知，顶级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。较少了解的是，中尺度强迫的时空变异性如何影响中间营养群落的跨陆架和沿陆架结构，以及从浮游动物和鱼类向顶级捕食者的碳转移。研究人员将利用2000年和2002年GLOBEC NEP多船调查俄勒冈州和加利福尼亚州北部水域期间收集的数据集，研究顶级捕食者(海洋哺乳动物、海鸟)、它们的猎物和加利福尼亚州北部洋流系统(CCS)中的中尺度和更精细尺度的空间和时间关系。由于气候在时间尺度上的变化，从天数(上升流)到年际变化(ENSO)到年代际(太平洋年代际涛动，PDO)，CCS生产力的变异性非常大。虽然这些趋势可以从大尺度上看得最清楚，但捕食者正在利用可用的猎物斑块，这是在中尺度或更精细的尺度上。将检验两个主要的零假设：1)中尺度强迫改变了沿岸上涌锋和赤道向喷流，不影响顶端捕食者的跨陆架和沿陆架的密度和群落结构；2)通过空间自相关测量的浮游生物和Nekton分布的空间尺度，在任何地方都可与物理参数的空间尺度相媲美；反过来，浮游生物或鱼类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年的数据构建一个影响顶级捕食者分布因素的预测模型，并将使用2002年的数据对其进行检验。他们还将使用通用的加法模型估计捕食者的数量和分布，并构建碳流模型，以估计上层营养水平排放、呼吸和封存的碳(以及候鸟移走的碳)。将使用几种建模方法来确定一系列规模的猎物对应或消耗的大小和重要性。空间异质性将在生态系统的两个层面上进行审查：捕食者相对于其猎物的密度或斑块大小相对于物理海洋特征，以及捕食者相对于其猎物的密度。本文提出的综合方法为本世纪初研究捕食者对CCS北部几个尺度和变异性来源的反应提供了有价值的基线。此外，这项合成还推进了CCS顶端捕食者(其中许多是濒危物种)发生模式的预测生物物理模型的长期发展。这些模型的演变将有助于资源管理和人类活动(例如，主要渔业、5个海洋保护区、运输和商业)在美国西海岸外的加利福尼亚州北部洋流生态系统中的规划。

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.