Klapwijk Maartje J
Department of Ecology Swedish University of Agricultural Sciences Uppsala Sweden.
Ecol Evol. 2019 Jul 17;9(16):9052-9060. doi: 10.1002/ece3.5451. eCollection 2019 Aug.
Natural enemy diversity is thought to be important for effective suppression of herbivores in production systems. Studies investigating the importance of the diversity and composition of the natural enemy complex often use within-year empirical studies or experimental exclusion setups.However, within-year population suppression might not translate in long-term population regulation. Therefore, I used a combination of long-term data collection and an exclusion experiment to investigate mechanisms behind year-to-year population changes and potential effects of disturbance of the natural enemy complex.Using the holly leaf miner study system in Wytham Woods, I find that the dominant predator in the system does not necessarily contribute the most to the reduction in year-to-year changes in mine density or within-patch fluctuations. Using the exclusion experiment, it becomes clear that parasitism later in the prey life cycle can to a certain level compensate for disruption of mortality in the earlier life stage of the prey.Thus, for host suppression in perennial systems the mortality pressure over the whole life cycle is important and disturbance during one part of the life cycle might not necessarily be buffered by mortality in other parts of the life cycle, especially if the natural enemy complex consists of multiple predator guilds.
天敌多样性被认为对于生产系统中有效抑制食草动物至关重要。研究天敌复合体的多样性和组成的重要性时，通常采用年内实证研究或实验性排除设置。然而，年内种群抑制可能无法转化为长期的种群调节。因此，我结合长期数据收集和一项排除实验，来研究逐年种群变化背后的机制以及天敌复合体受到干扰的潜在影响。利用怀瑟姆森林中的冬青潜叶虫研究系统，我发现该系统中的优势捕食者对矿坑密度逐年变化的减少或斑块内波动的贡献不一定最大。通过排除实验可以清楚地看到，猎物生命周期后期的寄生在一定程度上可以补偿猎物早期生命阶段死亡率的干扰。因此，对于多年生系统中的寄主抑制而言，整个生命周期的死亡压力很重要，生命周期某一阶段的干扰不一定能被生命周期其他阶段的死亡率所缓冲，尤其是当天敌复合体由多个捕食者类群组成时。
