The ecological and evolutionary legacy of extreme climatic events for food web resilience

极端气候事件对食物网恢复力的生态和进化遗产

• 批准号: NE/X000117/1
• 负责人: Owen Lewis
• 金额: $ 64.21万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX000117%2F1
• 关键词: ecological; evolutionary; legacy; extreme; climatic

There is growing evidence that extreme events such as heatwaves, rather than increases in average temperatures, will have the most immediate and harmful effects on plants and animals as the climate changes. This is particularly true for species-rich tropical ecosystems, where recent heatwaves have already caused severe population crashes for some species.Most studies investigating the impact of extreme climatic events on biodiversity focus on individual species in isolation. However, natural communities are complex, interacting networks of species, linked by competition, mutualism, predation and parasitism. We therefore need to understand what happens when whole communities of interacting species are subjected to a heatwave or other extreme climatic event, and how these effects change depending on the duration and intensity of the event. How resilient will the surviving populations and species be in the longer term, when faced with further extremes? The answer is likely to depend on both ecological responses (changes in the abundance and interactions of different species depending on their ecological tolerances), and evolutionary processes (the evolution of novel tolerances through natural selection). To understand fully how and why ecological communities are altered by extreme events, we need to carry out experiments simulating extreme conditions and follow the consequences over multiple generations. In most contexts such experiments would be practically or ethically impossible. However, we can design experiments that do exactly this by focusing on a special study system: food webs of Drosophila fruit flies and the parasitic wasps that consume them. At our study site in the rainforests of tropical Queensland, Australia, these flies and wasps form discrete ecological communities within individual rotting fruits. They have short generation times, allowing us to observe community responses to climate extremes in real time. Australian tropical rainforests are a high-diversity ecosystem that is threatened by climate change, and we expect rainforest insects to be particularly vulnerable because they are already operating close to the upper limits of their thermal tolerances: modest further increases in temperatures could make populations and communities unviable. These characteristics make our study system ideal for understanding the resilience of ecological systems to extreme climatic events.In our experiments, we will use heating cables in the rainforest to simulate heatwave conditions that are expected to affect Australian rainforests in the coming decades. We will then investigate the ecologically and evolutionary responses of individual species and the food web of interactions among them to further perturbations. By challenging communities that have previously been subjected to heat waves with further heat waves, we will be able to test under what conditions climatic extremes make communities more or less resilient to future shocks and understand the ecological and evolutionary mechanisms that underpin community resilience.

越来越多的证据表明，随着气候变化，热浪等极端事件，而不是平均温度的升高将对动植物产生最直接和最有害的影响。对于富含物种的热带生态系统而言，尤其如此，最近的热浪已经导致某些物种严重的人口崩溃。大多数研究研究了极端气候事件对生物多样性的影响，以孤立地关注各个物种。然而，自然社区是复杂的，相互作用的物种网络，与竞争，互惠，捕食和寄生虫相关。因此，我们需要了解当整个相互作用物种的社区受到热波或其他极端气候事件的影响，以及这些影响如何根据事件的持续时间和强度而变化。在面对进一步的极端时，尚存的人群和物种将如何韧性？答案很可能取决于生态反应（不同物种的丰度和相互作用的变化，取决于它们的生态耐受性）和进化过程（通过自然选择的新耐受性进化）。要充分了解极端事件的生态社区的方式以及为什么会改变生态社区，我们需要进行模拟极端条件并遵循多代后果的实验。在大多数情况下，这种实验实际上或道德上是不可能的。但是，我们可以通过专注于特殊研究系统来设计实现这一目标的实验：果蝇果蝇的食物网和食用它们的寄生黄蜂。在澳大利亚热带昆士兰州雨林的研究地点，这些苍蝇和黄蜂形成了单个腐烂水果中的离散生态群落。他们的生成时间很短，使我们能够实时观察社区对极端气候的反应。澳大利亚热带雨林是一个受气候变化威胁的高多样性生态系统，我们希望雨林昆虫尤其容易受到伤害，因为它们已经接近其热公差的上限：温度的适度升高可能会使人口和社区的种群和社区不可避免。这些特征使我们的研究系统非常适合了解生态系统对极端气候事件的弹性。在我们的实验中，我们将使用雨林中的加热电缆来模拟预计在未来几十年中会影响澳大利亚雨林的热浪条件。然后，我们将研究单个物种的生态和进化反应以及它们之间的相互作用的食物网，以进一步扰动。通过挑战以前曾经过进一步热浪的热浪的挑战，我们将能够在气候极端的条件下测试，使社区或多或少地使社区有抵御量的抗击，并了解基于社区抵御能力的生态和进化机制。