Threshold harvesting removes the surplus of a population above a set threshold and takes no harvest below the threshold. This harvesting strategy is known to prevent overexploitation while obtaining higher yields than other harvesting strategies. However, the harvest taken can vary over time, including seasons of no harvest at all. While this is undesirable in fisheries or other exploitation activities, it can be an attractive feature of management strategies where removal interventions are costly and desirable only occasionally. In the presence of population fluctuations, the issue of variable harvests and population sizes becomes even more notorious. Here, we investigate the impact of threshold harvesting on the dynamics of both population size and harvests, especially in the presence of population cycles. We take into account semelparous and iteroparous life cycles, Allee effects, observation uncertainty, and demographic as well as environmental stochasticity, using generic mathematical models in discrete time. Our results show that threshold harvesting enhances multiple forms of population stability, namely persistence, constancy, resilience, and dynamic stability. We discuss plausible choices of threshold values, depending on whether the aim is resource exploitation, pest control, or the stabilization of fluctuations.

阈值收割会去除高于设定阈值的剩余人口，并且不会收割低于阈值的收割。已知这种收割策略可以防止过度开采，同时获得比其他收割策略更高的产量。但是，收成会随时间变化，包括根本没有收成的季节。尽管这在渔业或其他开发活动中是不可取的，但它可能是管理策略的一个吸引人的特征，在这种策略中，移除干预的成本很高，并且仅在偶尔需要时才需要。在人口波动的情况下，可变收成和人口规模问题变得更加臭名昭著。在这里，我们调查阈值收获对种群规模和收获动态的影响，尤其是在种群周期存在的情况下。我们使用离散时间的通用数学模型考虑了同生命周期和异生命周期，阿利效应，观测不确定性，人口统计和环境随机性。我们的结果表明，阈值收获可以增强人口稳定性的多种形式，即持久性，恒定性，适应性和动态稳定性。我们讨论阈值的合理选择，这取决于目标是资源开发，害虫控制还是波动稳定。