Département de sciences biologiques, Institut de recherche en biologie végétale, Université de Montréal, Montréal, QC, Canada, H1X 2B2.
Glob Chang Biol. 2013 Mar;19(3):833-42. doi: 10.1111/gcb.12094. Epub 2012 Dec 29.
Greater climatic variability and extreme climatic events are currently emerging as two of the most important facets of climate change. Predicting the effects of extreme climatic events, such as heat waves, is a major challenge because they may affect both organisms and trophic interactions, leading to complex responses at the community level. In this study, we set up a simple three-level food chain composed of a sweet pepper plant, Capsicum annuum; an aphid, Myzus persicae; and a ladybeetle, Coleomegilla maculata, to explore the consequences of simulated heat waves on organism performance, trophic interactions, and population dynamics. We found that (1) heat waves do not affect plant biomass, significantly reduce the abundance and fecundity of aphids, and slightly affect ladybeetle developmental time and biomass, (2) heat waves decrease the impact of ladybeetles on aphid populations but do not modify the effect of aphids on plant biomass, and (3) food chains including predatory ladybeetles are more resistant to heat waves than a simple plant-aphid association, with aphid abundance being less influenced by heat waves in the presence of C. maculata. Our results suggest that more biodiverse ecosystems with predators exerting a strong biotic control are likely to be less influenced by abiotic factors and then more resistant to extreme climatic events than impoverished ecosystems lacking predators. Our study emphasizes the importance of assessing the effects of climatic change on each trophic level as well as on trophic interactions to further our understanding of the stability, resilience, and resistance of ecological communities under climatic forcing.
目前，气候变化的两个最重要方面是气候变异性增大和极端气候事件增多。预测极端气候事件（如热浪）的影响是一项重大挑战，因为它们可能同时影响生物和营养相互作用，导致群落层面的复杂响应。在这项研究中，我们构建了一个简单的三级食物链，由甜椒（Capsicum annuum）、烟粉虱（Myzus persicae）和龟纹瓢虫（Coleomegilla maculata）组成，以探索模拟热浪对生物表现、营养相互作用和种群动态的影响。结果发现：（1）热浪不会影响植物生物量，显著降低蚜虫的丰度和繁殖力，略微影响龟纹瓢虫的发育时间和生物量；（2）热浪降低了龟纹瓢虫对蚜虫种群的影响，但不改变蚜虫对植物生物量的影响；（3）包含捕食性龟纹瓢虫的食物链比简单的植物-蚜虫组合更能抵抗热浪，在有 C. maculata 存在的情况下，蚜虫丰度受热浪影响较小。研究结果表明，与缺乏捕食者的贫瘠生态系统相比，生物多样性更高、捕食者具有更强生物控制作用的生态系统可能受非生物因素的影响较小，因此在面对极端气候事件时更具抵抗力。本研究强调了评估气候变化对每个营养水平以及营养相互作用的影响的重要性，以进一步了解在气候胁迫下生态群落的稳定性、弹性和抵抗力。
