A Novel Testing Paradigm to Identify and Manage Multiple Stressor Impacts on Wildlife

生物多样性正在以惊人的速度下降。多种压力因素导致了这些下降，淡水生态系统受到的影响尤其严重。短暂的生态系统（如沼泽、池塘）具有特别的生物多样性和高度暴露于各种环境压力，但在学术界和监管中通常被忽视。两栖动物是这些栖息地的主要动物组成部分，至少有3.5亿年的历史，它们高度进化到这些生态系统。两栖动物和湿地是全球最受威胁的门/生态系统，湿地健康是气候危机的关键，因为人类影响的系统排放了大量的甲烷。在这里，我们将使用现场和实验室的方法，研究环境压力源组合对两栖动物（普通青蛙，临时蛙）的负面影响，并寻求开发一种生物监测方法来评估这些重要生态系统的健康状况。由于两栖动物是最受威胁的脊椎动物门，该项目与保护重点高度相关。将测量野生和圈养蝌蚪的一般健康状况、疾病状况、应激标志物和全球基因表达。利用毒物基因组学和生理变化来评估对蝌蚪的影响，既可以将分子启动事件锚定到下游生理终点和由此产生的逆境，也可以将这些反应映射到应激源组合中。这种图谱提出了一种非常新颖的方法，可以识别导致负面影响的特定压力源及其组合，并广泛适用于整个生物群。流域尺度的野生分类群与压力源的存在/严重程度之间的生态流行病学研究通常将污染列为驱动浮游生物负面影响的最重要变量之一。然而，关于污染在环境相关水平和混合组合方面的影响的研究很少，特别是在多重压力源的情况下。在这里，污染物混合物的配方将直接基于短暂鱼类的测量水平，并结合其他无处不在的压力源（盐度、热浪和/或入侵小龙虾-太平洋小龙虾），所有这些都是与环境相关的水平和组合。这些实验室暴露将是非常新颖的，对于理解多重压力源对栖息在重要的短暂生态系统中的标志性两栖动物的真正影响至关重要。它将测试如何最好地利用来自单一压力源暴露的数据，使用理论模型预测影响。为此，我们将应用新的理论范式-优势（少数压力源对观察到的效应贡献不成比例）和负担（总压力源负荷决定效应）-这在多压力源科学中具有广泛应用的巨大潜力。与单端点方法相反，我们建议使用生态模型来研究对整个生物体及其种群的影响，以便大大提高这些数据在保护中的效用。最后，通过移植卵并对笼养蝌蚪和本地蝌蚪进行取样，将评估naïve/本地适应蝌蚪作为评估FW湿地健康的生物监测工具的效用。这项工作将解决文献中基于现场的流域级证据之间的重要差距，这些证据表明了多种应激源的重要性，而目前有限的基于实验室的证据/理解；并开发了一种具有实际应用价值的新测试范例。研究团队综合了本项目所需的FW生态毒理学、多压力源/混合效应生物学、FW生态学、生态建模、生物信息学和化学等方面的优势。此外，项目合作伙伴和支持组织包括一系列关注FW生态系统健康和减少污染影响的利益相关者。

Biodiversity is declining at an alarming rate. Multiple stressors are driving many of these declines with freshwater (FW) ecosystems particularly impacted. Ephemeral FWs (e.g. marshes, ponds) are exceptionally biodiverse and highly exposed to varied environmental stressors but are generally overlooked within academia and regulation. Amphibians have been a major faunal component of these habitats for at least 350 million years, being highly evolved to these ecosystems. Amphibians and wetlands are some of the most highly threatened Phyla/ecosystems globally, with wetland health key to the climate crisis, due to the high methane levels emitted from human impacted systems. Using both field and laboratory approaches, here we will investigate the environmental stressor combinations driving negative impacts in amphibians (common frog, Rana temporaria) and seek to develop a biomonitoring approach to assess the health of these vital ecosystems. As amphibians are the most highly threatened vertebrate Phyla, this project is highly relevant to conservation priorities. General health, disease status, stress markers and global gene expression in wild and caged tadpoles will be measured. The use of toxicogenomics and alterations to physiology to assess impacts on tadpoles allows both the anchoring of molecular initiating events to downstream physiological endpoints and resulting adversity, as well as mapping these responses to stressor combinations. This mapping presents a highly novel approach, allowing the identification of specific stressors and their combinations that are driving negative impacts, and is widely applicable across biota. Catchment-scale eco-epidemiological studies between wild taxa and the presence/severity of stressors often rank pollution as amongst the most important variables driving negative effects in FWs. However, studies on effects of pollution at environmentally relevant levels and mixture combinations are scarce, particularly in the context of multiple stressors. Here pollutant mixture formulations will be based directly on measured levels in ephemeral FWs and combined with other ubiquitous stressors (salinity, heat wave and/or invasive crayfish - Pacifasticus leniusculus cue), all at environmentally relevant levels and combinations. These laboratory exposures will be highly novel and of vital importance to understand the true impacts of multiple stressors on iconic amphibian biota that inhabit vital ephemeral FWs. It will be tested how best to utilise data from single stressor exposures, to predict effects using theoretical models. For this, we will apply novel theoretical paradigms to the data - dominance (few stressors contribute disproportionately to observed effects) and burden (total stressor load determines effects) - which have huge potential for wide applicability for multi-stressor science. In contrast to the single-endpoint approach, here we propose to use ecological modelling to investigate effects on whole organisms and their populations in order to drastically improve the utility of these data for conservation. Finally, by transplanting spawn and sampling both caged and native tadpoles, the utility of naïve/locally adapted tadpoles as a biomonitoring tool to assess the health of FW wetlands will be assessed. This work will address an important gap in the literature between field-based catchment-level evidence demonstrating the importance of multiple stressors and the current limited laboratory-based evidence/understanding; as well as developing a new testing paradigm with practical application for conservation. The research team combines excellence in FW ecotoxicology, multiple stressors/mixture effect biology, FW ecology, ecological modelling, bioinformatics and chemistry needed for this project. In addition, the project partners and supporting organisations comprise a range of stakeholders that are focused on the health of FW ecosystems and reducing the impacts of pollution.