Department of Biological Sciences, University of Alberta, CW 405 Biological Sciences Bldg, Edmonton, AB T6G 2E9, Canada.
Department of Biological Sciences, University of Alberta, CW 405 Biological Sciences Bldg, Edmonton, AB T6G 2E9, Canada; Mathematical and Statistical Sciences, University of Alberta, 632 CAB, Edmonton, AB T6G 2G1, Canada.
J Environ Manage. 2020 Apr 15;260:110167. doi: 10.1016/j.jenvman.2020.110167. Epub 2020 Jan 25.
The efficacy of direct control methods in bark beetle outbreaks is a disputed topic. While some studies report that control reduces tree mortality, others see little effect. Existing models, linking control rate to beetle population dynamics and tree infestations, give insights, but there is a need to take into account the environment spatial variability and its impact on beetle life cycle. Here, we use natural variability found in a carefully monitored and controlled infestation to simulate outbreak dynamics under different control effort and to explore the impact of control on outbreaks suppression and tree mortality. Our semi-empirical predictive model of the number of infested trees as a function of ecological and environmental variables is coupled to a simulation model for infestation dynamics. We show that even a little control can have a major impact on the number of infested trees after several years of sustained effort. However, a moderate control of 60% is required to reduce the beetle population on the long term. Furthermore, a control rate of 69%-83% is needed to achieve outbreak suppression in under 13 years depending on the abundance of incoming flights from outside sources.
直接控制方法在树皮甲虫爆发中的效果是一个有争议的话题。虽然一些研究报告称控制可以降低树木死亡率，但也有一些研究几乎没有看到效果。现有的将控制率与甲虫种群动态和树木侵染联系起来的模型提供了一些见解，但需要考虑环境空间变异性及其对甲虫生命周期的影响。在这里，我们利用在经过精心监测和控制的侵染中发现的自然变异性，模拟不同控制力度下的爆发动态，并探讨控制对爆发抑制和树木死亡率的影响。我们将侵染树木数量的半经验预测模型与侵染动态模拟模型相结合，该模型是基于生态和环境变量的。我们表明，即使是少量的控制，在持续多年的努力之后，也会对侵染树木的数量产生重大影响。然而，需要进行适度的 60%的控制，才能在长期内降低甲虫种群数量。此外，根据外部来源传入飞行物的丰度，需要 69%-83%的控制率才能在 13 年内实现爆发抑制。
