Trends and cohort resonant effects in age-structured populations
Trends and cohort resonant effects in age-structured populations
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DOI：
10.1111/j.0021-8790.2004.00888.x
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发表时间：
2004-11-01
影响因子：
4.8
通讯作者：
Fromentin, JM
中科院分区：
文献类型：
--
作者：
Bjornstad, ON;Nisbet, RM;Fromentin, JM
1.种群的趋势和波动是由外在强迫和内在动力之间复杂的相互作用决定的。作为一个例子，许多海洋鱼类的动态特征是年龄结构的动态被迫随机招聘。在这项研究中，我们开发了两个案例研究，大西洋蓝鳍金枪鱼和大西洋鳕鱼的随机年龄结构模型。前者证实了群体内相互作用和密度依赖性繁殖，后者证实了密度依赖性生存和群体间相互作用.我们使用传递函数和延迟坐标模型来研究年龄结构的相互作用和随机招聘的组合如何引起低频变异。我们称这种效应为“群体共振”，它可以引起明显的丰度趋势，在年龄结构的人群中可能很常见。我们的研究补充了结构化种群理论，该理论侧重于周期和混沌（高频动力学）。我们所描述的固有低频波动可能会模拟或掩盖与环境变化、过度开发或其他类型的人为强迫有关的丰度的关键变化。从管理和保护的角度来看，重要的是要找到办法，从队列共振效应和/或了解它们的相互作用方式分开人为强迫。
1. Trends and fluctuations in populations are determined by complex interactions between extrinsic forcing and intrinsic dynamics. As an example, the dynamics of many marine fish are characterized by age-structured dynamics forced by stochastic recruitment.2. In this study we develop stochastic age-structured models for two case studies, the Atlantic bluefin tuna and the Atlantic cod. The former exemplifies intracohort interactions and density-dependent reproduction, the latter exemplifies density-dependent survival and intercohort interactions.3. We use transfer functions and delay-coordinate models to study how the combination of age-structured interactions and stochastic recruitment can induce low-frequency variability. 'Cohort resonance', as we dub this effect, can induce apparent trends in abundance and may be common in age-structured populations.4. Our study complements the theory of structured populations that focuses on cycles and chaos (high-frequency dynamics).5. The innate low-frequency fluctuations we describe can potentially mimic or cloak critical variation in abundance linked to environmental change, over-exploitation or other types of anthropogenic forcing.6. From a management and conservation viewpoint, it will be important to find ways to separate anthropogenic forcing from cohort resonant effects and/or to understand the way they interact.