Fast behavioral feedbacks make ecosystems sensitive to pace and not just magnitude of anthropogenic environmental change
Fast behavioral feedbacks make ecosystems sensitive to pace and not just magnitude of anthropogenic environmental change
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DOI：
10.1073/pnas.2003301117
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发表时间：
2020-10-13
影响因子：
11.1
通讯作者：
Hein, Andrew M.
中科院分区：
文献类型：
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作者：
Gil, Michael A.;Baskett, Marissa L.;Hein, Andrew M.
人为的环境变化正在改变世界各地生态系统中动物的行为。虽然行为通常发生在比人口统计快得多的时间尺度上，但它仍然可以影响人口统计过程。在这里，我们使用详细的数据，从珊瑚礁生态系统的行为和经验估计的人口发展一个耦合behavioraldemographic生态系统模型。模型的分析表明，行为和人口相互反馈，以确定生态系统如何响应人为强迫。特别是，经验观察到的草食性鱼类的密度和觅食行为之间的反馈导致替代稳定的生态系统状态的珊瑚种群的持久性或崩溃（和完整的藻类优势）。这种反馈使生态系统更容易在捕捞压力下珊瑚崩溃，但也更容易随着捕捞量的减少而恢复。此外，由于行为反馈，生态系统对捕捞压力变化的反应不仅取决于捕捞变化的幅度，还取决于施加变化的速度。例如，迅速增加捕鱼量到一定水平可能会破坏一个在渐进变化下持续存在的生态系统。我们的研究结果揭示了外部强迫的速度而不仅仅是强度可以决定生态系统对环境变化的反应的条件。更一般地说，我们的多尺度行为人口框架演示了如何将高分辨率行为数据纳入生态模型，以更好地了解生态系统将如何应对扰动。
Anthropogenic environmental change is altering the behavior of animals in ecosystems around the world. Although behavior typically occurs on much faster timescales than demography, it can nevertheless influence demographic processes. Here, we use detailed data on behavior and empirical estimates of demography from a coral reef ecosystem to develop a coupled behavioraldemographic ecosystem model. Analysis of the model reveals that behavior and demography feed back on one another to determine how the ecosystem responds to anthropogenic forcing. In particular, an empirically observed feedback between the density and foraging behavior of herbivorous fish leads to alternative stable ecosystem states of coral population persistence or collapse (and complete algal dominance). This feedback makes the ecosystem more prone to coral collapse under fishing pressure but also more prone to recovery as fishing is reduced. Moreover, because of the behavioral feedback, the response of the ecosystem to changes in fishing pressure depends not only on the magnitude of changes in fishing but also on the pace at which changes are imposed. For example, quickly increasing fishing to a given level can collapse an ecosystem that would persist under more gradual change. Our results reveal conditions under which the pace and not just the magnitude of external forcing can dictate the response of ecosystems to environmental change. More generally, our multiscale behavioral-demographic framework demonstrates how highresolution behavioral data can be incorporated into ecological models to better understand how ecosystems will respond to perturbations.