Oxidative stress and climate change: effects of elevated temperatures on oxidative status, fertility and ageing in a tropical species of conservation concern

了解动物物种对气候变化的反应对于确定气候变化对它们在自然栖息地的生存构成的威胁至关重要。由于气候变暖导致的温度升高与健康恶化之间的关系潜在的一个关键生理学候选者是氧化应激（即活性氧（ROS）的产生与抗氧化防御之间的不平衡）。事实上，暴露于高温会增加ROS的产生和对氧化应激的敏感性，这反过来可能会对生育力、衰老和生存产生负面影响。这些影响对热带物种最为严重，这些物种对温度上升的耐受性有限，在其自然栖息地已经经历了接近其临界温度上限的温度。要表征的威胁，由于气候变暖的氧化变化可能构成的热带物种的保护问题，我将首先描述的氧化应激和健身组件在近威胁的黄喉燕雀（刺桐）热条件下施加的影响。为了达到这些目的，我将测量暴露于不同温度条件和膳食抗氧化剂的可用性对（i）氧化标志物的伴随影响（氧化损伤和抗氧化防御），（ii）生育力和生殖力标志物（精子质量、卵子生产、生殖性能）和（iii）衰老（通过端粒缩短测量）。这种综合方法，符合新兴的保护生理学领域，将首次在气候变化的背景下建立热条件和氧化平衡之间的联系。这种创新的方法将为气候诱导的氧化应激对热带物种衰退及其抵抗气候变化的能力的潜在影响提供新的见解。

Understanding the response of animal species to climate variation is of primary importance to characterize the threat that climate change will constitute for their maintenance in their natural habitat. One key physiological candidate potentially underlying the relationship between elevated temperature due to climate warming and fitness deterioration is oxidative stress (i.e. the imbalance between the production of Reactive Oxygen Species (ROS) and antioxidant defences). Indeed, exposure to elevated temperatures increases ROS production and susceptibility to oxidative stress, which may in turn negatively impact fertility, ageing and survival. These effects should be most critical in tropical species with limited tolerance to temperature increase and already experiencing temperatures close to their upper critical temperature in their natural habitat. To characterize the threat that oxidative changes due to climate warming may constitute for a tropical species of conservation concern, I will first characterize the effects imposed by hot conditions in terms of oxidative stress and fitness components in the near-threatened Gouldian finch (Erythrura gouldiae). I will then test whether deleterious effects of elevated temperature on oxidative markers and fitness components can be alleviated by the consumption of natural food resources of high antioxidant potency.To achieve these objectives, I will measure the concomitant effects of exposure to different temperature conditions and of the availability of dietary antioxidants on (i) oxidative markers (oxidative damage and antioxidant defences), (ii) fertility and fecundity markers (sperm quality, egg production, reproductive performance) and (iii) ageing (measured through telomere shortening).This integrative approach, in line with the emerging field of conservation physiology, will establish for the first time a link between thermal conditions and oxidative balance in the context of climate change. This innovative approach will provide a novel insight into the potential implications of climate induced oxidative stress for the decline of tropical species and their capacity to resist climate changes.