VKR Centre for Ocean Life, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
J Theor Biol. 2021 Aug 21;523:110663. doi: 10.1016/j.jtbi.2021.110663. Epub 2021 Apr 20.
Individuals of different interacting populations often adjust to prevailing conditions by changing their behavior simultaneously, with consequences for trophic relationships throughout the system. While we now have a good theoretical understanding of how individuals adjust their behavior, the population dynamical consequences of co-adaptive behaviors are rarely described. Further, mechanistic descriptions of ecosystem functions are based on population models that seldom take behavior into account. Here, we present a model that combines the population dynamics and adaptive behavior of organisms of two populations simultaneously. We explore how the Nash equilibrium of a system - i.e. the optimal behavior of its constituent organisms - can shape population dynamics, and conversely how population dynamics impact the Nash equilibrium of the system. We illustrate this for the case of diel vertical migration (DVM), the daily movement of marine organisms between food-depleted but safe dark depths and more risky nutrition-rich surface waters. DVM represents the archetypal example of populations choosing between a foraging arena (the upper sunlit ocean) and a refuge (the dark depths). We show that population sizes at equilibrium are significantly different if organisms can adapt their behavior, and that optimal DVM behaviors within the community vary significantly if population dynamics are considered. As a consequence, ecosystem function estimates such as trophic transfer efficiency and vertical carbon export differ greatly when fitness seeking behavior is included. Ignoring the role of behavior in multi-trophic population modeling can potentially lead to inaccurate predictions of population biomasses and ecosystem functions.
不同相互作用的种群的个体通常会通过同时改变行为来适应流行的环境条件，这会对整个系统中的营养关系产生影响。虽然我们现在对个体如何调整行为有很好的理论理解，但协同适应行为的种群动态后果很少被描述。此外，生态系统功能的机制描述基于很少考虑行为的种群模型。在这里，我们提出了一个同时结合两个种群的生物种群动态和适应性行为的模型。我们探索了系统的纳什均衡（即其组成生物体的最佳行为）如何塑造种群动态，以及相反，种群动态如何影响系统的纳什均衡。我们以昼夜垂直迁移（DVM）为例来说明这一点，即海洋生物在食物匮乏但安全的黑暗深处和更危险的营养丰富的水面之间的日常移动。DVM 代表了种群在觅食场（阳光充足的海洋上层）和避难所（黑暗深处）之间进行选择的典型例子。我们表明，如果生物体能够适应其行为，那么在平衡时的种群规模会有显著差异，如果考虑种群动态，那么社区内的最佳 DVM 行为会有显著差异。因此，如果包括寻求适应性行为，那么生态系统功能估计，如营养转移效率和垂直碳输出，会有很大差异。在多营养层次种群建模中忽略行为的作用可能会导致对种群生物量和生态系统功能的预测不准确。
