Functional responses and ecosystem dynamics: how clearance rates explain the influence of satiation, food-limitation and acclimation
Functional responses and ecosystem dynamics: how clearance rates explain the influence of satiation, food-limitation and acclimation
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DOI：
10.1093/plankt/fbn078
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发表时间：
2008-11-01
影响因子：
2.1
通讯作者：
Neuheimer, A. B.
中科院分区：
文献类型：
--
作者：
Gentleman, W. C.;Neuheimer, A. B.
建模人员很早就意识到，浮游动物死亡或闭合的数学形式对浮游生态系统模型的动力学有很大影响。另一个重要的公式是功能反应，即摄食率如何随着猎物密度的变化而变化。在这里，我们解释为什么不同的放牧反应会对建模的动态产生截然不同的影响，以及常见的做法如何由于对取食行为的误导描述而限制模型。在营养-浮游植物-浮游动物(NPZ)模型中使用不同的摄食功能会导致密度波动而不是恒定。与以前的研究结论相反，研究表明，这些结果并不是由于浮游动物饱和与不饱和造成的。通过对捕食者-食饵模型的分析，得到了与食物限制捕获率有关的生态稳定的必要条件。敏感性研究表明，浮游动物清除率对更复杂的模型的动力学有很大的影响。此外，研究表明，驯化时间滞后可以显著改变浮游动物对猎物密度变化的适应结果，这是由于对捕获率的必然影响。这些结果将作为对模型师的实用建议，这些模型师在选择功能反应的表达时面临不确定性。
Modellers have long been aware that the mathematical form of zooplankton mortality, or closure, significantly affects the dynamics of planktonic ecosystem models. Another important formulation is the functional response, i.e. how ingestion rates change with prey density. Here we explain why different grazing responses can have profoundly differing influences on modelled dynamics, and how common practices may limit models due to misguided characterization of feeding behaviours. Use of different ingestion functions in a Nutrient-Phytoplankton-Zooplankton (NPZ) model results in oscillating versus constant densities. Contrary to the conclusions of previous studies, it is shown that these results are not due to zooplankton satiation versus non-satiation. Analysis of a predator-prey model is used to derive the necessary condition for ecological stability, which is related to food-limited clearance rates. Sensitivity studies demonstrate that zooplankton clearance rates have a strong influence on the dynamics of more complex models. Moreover, it is shown that acclimation time lags can dramatically alter results from those where zooplankton instantly adapt to changing prey densities due to the corollary effect on clearance rates. These results are discussed in terms of practical advice to modellers who face uncertainty in choosing expressions for the functional response.