Thermal tolerance and the response of freshwater communities to multiple stressors

加拿大人比世界上任何其他国家都要管理更多的内陆水体，这是一种独特的资源，我们致力于通过《加拿大水法》保护这一资源。然而，淡水生态系统面临着许多威胁，包括与流域土地使用有关的污染，以及由于定向气候变化和更频繁的热浪造成的沃茨变暖。要预测这些威胁对淡水生物多样性的影响，就需要评估它们的相互影响，即它们单独和共同作用时的影响。我的研究计划将解开气候变暖和农业污染对加拿大淡水动物（浮游生物和鱼类）的相互影响。我以前的研究表明，农业污染会对淡水生态系统造成广泛的生态和进化影响，社区会增加和减少物种，种群会随着流域土地利用的变化而进化（改变其特征）。我现在要问的是，这些变化是否会使社区对气候变暖的容忍度提高或降低。我的研究计划围绕三个目标。首先，使用“大数据”方法，我的团队将估计数百种湖泊浮游生物和鱼类的耐热性。然后，我们将使用两个大型的标准化调查浮游动物（664个湖泊在加拿大）和鱼类（768个湖泊在魁北克省）从不同的流域土地利用（从原始到高度农业）和量化的“平均耐热性”的动物在这些湖泊。第二，我们将依靠最先进的实验设施，在98个实验池塘中使浮游生物群落暴露于农业污染。我们将进行一项独特的大规模实验，根据实地数据将浮游生物暴露于两种梯度的农业污染。我们将跟踪生态和进化反应，然后将社区暴露于实验性但现实的热浪事件中，以测试污染是否会影响耐热性。最后，我们将从不同流域土地利用的湖泊中采集浮游动物和鱼类样本，并利用已建立的生理学测定方法测量它们的耐热性。这将使我们能够确定在原始与污染地点发现的种群（相同物种）是否在耐热性方面存在差异。作为一个整体，该计划将评估农业土地利用和气候变化是否可能对湖泊动物产生叠加或交互（拮抗或协同）影响。这些信息将使我们能够更好地预测和管理加拿大湖泊的生物多样性变化，这些湖泊面临着气候变暖和流域农业加剧的问题。

Canadians are the stewards of more inland water bodies than any other country in the world, a unique resource we have committed to preserve via the Canada water act. Yet, freshwater ecosystems face a number of threats that include pollution linked to watershed land use, and warming waters due to directional climate change and more frequent heat waves. Predicting impacts of these threats on freshwater biodiversity requires an assessment of their interactive effects, namely their impact when acting individually and when acting in combination. My research program will disentangle the interactive effects of climate warming and agricultural pollution on freshwater animals (plankton and fish) in Canada. My previous research has shown that agricultural pollution causes widespread ecological and evolutionary effects in freshwater ecosystems, with communities gaining and losing species and with populations evolving (changing their traits) in response to watershed land use. I will now ask whether these changes make communities more or less tolerant of a warming climate. My research program is centered around three objectives. First, using a 'big data' approach, my team will estimate the thermal tolerance of hundreds of species of lake plankton and fish. We will then use two large standardized surveys of zooplankton (664 lakes across Canada) and fish (768 lakes in Québec) from lakes that differ in watershed land use (from pristine to highly agricultural) and quantify the 'mean thermal tolerance' of animals in these lakes. Second, we will rely on a state-of-the-art experimental facility to expose plankton communities to agricultural pollution in 98 experimental ponds. We will conduct a unique large-scale experiment, exposing plankton to two gradients of agricultural pollution based on field data. We will track ecological and evolutionary responses, and then expose communities to an experimental but realistic heat wave event to test whether pollution influenced thermal tolerance. Finally, we will sample zooplankton and fish from lakes that differ in watershed land use and measure their thermal tolerance with established physiological assays. This will allow us to determine whether populations (of the same species) found in pristine vs. polluted sites differ in their thermal tolerance. As a whole, this program will assess whether agricultural land use and climate change are likely to have additive or interactive (antagonistic or synergistic) effects on lake animals. This information will allow us to better predict and manage biodiversity change in Canadian lakes facing a warming climate and intensifying agriculture in their watersheds.