An integrative approach to reveal community responses to multiple stressors

据估计，全球生物多样性的下降涉及的物种损失是人类压力开始之前的几倍，在淡水生态系统中最为明显。在这里，生态学家经常对这些新颖而极端的人为环境变化或“应激源”的累积影响感到惊讶，特别是当它们的综合影响不等于它们已知的单独影响的总和时。虽然许多研究集中在应激源的性质及其相互作用来解释这种非相加效应，但相对较少考虑受影响物种本身及其相互作用如何调节群落反应和生态系统过程(例如初级生产)。因此，在社区生态学中没有一个完善的概念框架，可以在此基础上进行经验性调查，以检验多种应激源的净影响。 在这里，我着重于对经常被引用的物种共同耐受性概念(SCC)进行实证升级，以推动它作为一种工具，从主要是淡水的角度揭示社区对多种压力来源的反应的性质。SCC的主要宗旨是，不同应激源的物种耐受性的相关性决定了它们对群落水平特性(例如，物种丰富度、总产量)的综合影响；然而，它仍然需要假设检验和进一步完善。我们最近的发现指出，SCC需要一个改进的基于物种的零模型，还需要更好地整合物种相互作用及其特征，以使其更具预测性和机械洞察力。在接下来的五年里，我的短期目标包括确定将这些因素整合到SCC中如何影响其突破性预测的潜力，以及了解社区对同时或连续暴露于应激源的反应。 HQP的广泛培训是我研究项目成功的核心。我亲自指导和协助HQP设计和启动现场和实验室研究，随后进行量化分析，并就他们的发现进行沟通。我采取了一种全面的方法来培训HQP的标准和新的和先进的藻类和无脊椎动物分类技术，开发在环境部门日益需求但短缺的技能集。我还鼓励在我的实验室中积极传授技能，以发展高级实验室成员的导师关系，同时也强烈鼓励建立一个高度协作和多样化的实验室环境。我特别兴奋的是，我们的发现将通过将群落生态学更多地放在全球变化的背景下，同时解决对多种应激源的累积生态影响进行更好的环境风险评估的需要，从而导致在教科书上改变群落生态学的进展。

Global decline in biodiversity is estimated to involve a several-fold greater loss of species than before the onset of human pressures, being most pronounced in freshwater ecosystems. Here, ecologists are often surprised by the cumulative impacts of these novel and extreme anthropogenic environmental changes, or "stressors," especially when their combined effect does not equal the sum of their known individual effects. While much research has focused on the properties of the stressors and their interactions to explain such non-additive effects, relative little consideration has been given to how the affected species themselves and their interactions may mediate community responses and ecosystem processes (e.g., primary production). Consequently, there does not exist a well-developed conceptual framework in community ecology upon which empirical investigations can be built to examine the net effects of multiple stressors. Here, I focus on empirically upgrading the often cited Species Co-tolerance Concept (SCC) to advance it as a tool for revealing the nature of community responses to multiple stressors from a mainly freshwater perspective. The primary tenet of the SCC is that the correlation of species tolerances of various stressors determines their combined impact on community-level properties (e.g., species richness, total production); however, it has remained in need of hypothesis-testing and further refinement. Our recent discoveries point to the SCC requiring an improved species-based null model, and also better integration of species interactions and their traits to make it more predictive and mechanistically insightful. Over the next five years, my short term objectives involve determining how integration of these factors into the SCC affect its potential for groundbreaking predictions and understanding of community responses to simultaneous or sequential exposures to stressors. Extensive training of HQP is at the core to the success of my research program. I personally mentor and assist HQP in their design and start of field and lab studies, subsequent quantitative analyses, and communication of their findings. I take a comprehensive approach to training HQP in standard to novel and advanced algal and invertebrate taxonomic techniques, developing skill sets that are increasingly in demand yet short in supply in the environmental sector. I also foster active transfer of skills in my lab to develop mentorship in senior lab members, while also strongly encouraging a highly collaborative and diverse lab environment. I am particularly excited that our findings will lead to textbook-changing advances in community ecology by placing it more in a global change context while also addressing the need for better environmental risk assessment of the cumulative ecological impacts of multiple stressors.