Mechanisms of plant and ecosystem responses to climate warming and increased atmospheric nitrogen deposition in temperate regions

我的研究目标是确定植物和生态系统对气候变化和北方温带地区工业和农业来源的大气氮污染增加的反应。 虽然这两个因素预计将在下一个世纪对植物和生态系统产生重大影响，但它们之间的潜在相互作用仍不清楚。 根据我以前使用NSERC发现补助金进行的初步研究，我假设，虽然较长的生长季节可能会增加植物生长，但变暖和更极端的气候事件导致的积雪减少可能会增加土壤冻结的强度，这可能会损害植物和土壤生物，导致土壤氮流失增加，植物生长减少。 我将探讨的背景下，我已经建立了一个长期的实验，在伦敦，ON.除了监测植物对变暖的反应（管理使用架空加热器）和氮的综合影响的变暖和氮添加，我正在研究的途径，其中氮是从土壤中损失的治疗。 我还将研究植物冻结反应在受控的实验室条件下，并在外地，以确定土壤冻结如何影响根氮吸收。 除了我对植物和氮的研究之外，我还将在实地实验的背景下探索整个生态系统的反应。 我将研究食草动物和分解者的活动如何改变我们对植物对实验处理的反应的看法。 我还将测量变暖和氮增加在多大程度上改变了生态系统二氧化碳的释放和遏制。 这些数据对于预测气候变化的生物反馈将如何影响未来的温室气体浓度尤为重要。 总的来说，我的研究将有重要的影响，自然植物群落和农业系统的管理，并预测如何生态系统服务可能会改变，以应对全球变化，在未来世纪。

My research objective is to determine plant and ecosystem responses to climate change and increased atmospheric nitrogen pollution from industrial and agricultural sources in northern temperate regions. While both of these factors are expected to have substantial effects on plants and ecosystems over the next century, their potential interactions remain unclear. Based on preliminary studies conducted using my previous NSERC Discovery Grant, I hypothesize that while a longer growing season might be expected to increase plant growth, reduced snow cover caused by warming and more extreme climate events will likely increase the intensity of soil freezing, which can damage plants and soil organisms, leading to increased soil nitrogen losses and reduced plant growth. I will explore the combined effects of warming and nitrogen addition in the context of a long-term experiment I have established in a grass-dominated field in London, ON. In addition to monitoring the plant responses to warming (administered using overhead heaters) and nitrogen addition, I am examining the pathways by which nitrogen is lost from the soil in response to the treatments. I will also study plant freezing responses under controlled laboratory conditions and in the field to determine how soil freezing influences root nitrogen uptake. In addition to my research on plants and nitrogen, I will explore entire ecosystem responses in the context of my field experiment. I will examine how the activities of herbivores and decomposers alter our perception of how the plants respond to the experimental treatments. I will also measure the extent to which warming and increased nitrogen alter the release and containment of carbon dioxide by the ecosystem. These data are particularly important for predicting how biological feedbacks to climate change will influence future greenhouse gas concentrations. Overall, my research will have important implications for the management of natural plant communities and agricultural systems and for predicting how ecosystem services may change in response to global change over the next century.