ETBC: Collaborative Research: Quantifying the Effects of Large-Scale Vegetation Change on Coupled Water, Carbon, and Nutrient Cycles: Beetle Kill in Western Montane Forests

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。对大规模植被变化对水、碳和养分循环耦合的影响进行量化：西山地森林的甲虫死亡我们正在量化与西部山地森林中的山松甲虫(MPB)侵袭相关的森林结构和组成的快速、广泛变化如何影响水、碳和氮循环的耦合。MPB侵染和相关的真菌病原体通过杀死寄主树木、改变表面能量和水分分配、减少碳吸收以及在短时间和长时间尺度上将有机质输入土壤，从根本上改变了生态系统的结构。这种干扰的广泛程度对政府和资源管理人员构成了重大挑战，他们必须对这些变化作出反应，但缺乏对这些系统将如何应对各种时间和空间尺度上的干扰的预测性了解。这种干扰使我们能够测试新兴的理论，即植被变化对耦合的生物地球化学循环的直接和间接影响，在最初只改变活生物量而保持土壤水文和化学特征不变的干扰之后。通过在具有不同MPB影响水平的地点工作，我们正在评估树木功能的急剧丧失如何直接(即蒸腾和固碳)和间接(即雪捕获、再分配和地表能量平衡)影响水、碳和氮的循环。我们的工作围绕着两个广泛的问题进行组织，这两个问题既需要跨学科的方法，也需要观察和建模的紧密结合。与MPB相关的植被结构的变化如何改变能量和水的分配？能源和水可获得性的这些变化如何影响地方到区域尺度的生物地球化学循环？我们已经组建了一个由生物地球化学家、生态学家、水文学家和大气科学家组成的不同团队，利用每个学科的测量、建模工具和概念方法来解决这些问题。我们的方法包括密集、协调的水文、生物地球化学和生态观测，旨在量化水、碳和养分循环的内部耦合，以及这些过程如何在陆地表面-大气交换和流域溶质输出中表达。这些观察结果与两个过程模型紧密结合在一起，一个来自地表群落，另一个来自集水区，以评估我们目前对植被变化如何改变耦合循环的理解。为了将我们的工作扩展到相对较短的时间尺度之外，我们与几个正在进行的项目进行协调，包括Boulder Creek CZO和Niwot Ridge LTER。通过量化森林植被对水和生物地球化学循环的生物和物理控制，我们的项目将提高我们对水、能量、碳和氮之间耦合的基本理解。通过与地面和集水区模型社区的协调，我们将把这些知识纳入更广泛的社区。我们的教育活动建立在所有机构成功努力的基础上，而与土地和水资源管理人员的协调将确保我们的知识转移到应用科学界。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Quantifying the Effects of Large-Scale Vegetation Change on Coupled Water, Carbon and Nutrient Cycles: Beetle Kill in Western Montane ForestWe are quantifying how rapid, extensive changes in forest structure and composition associated with Mountain Pine Beetle (MPB) infestation of western montane forests affect the coupling of water, carbon, and nitrogen cycles. MPB infestation and associated fungal pathogens radically change ecosystem structure by killing host trees, altering surface energy and water partitioning, reducing carbon uptake, and putting organic matter into soil on short and long time scales. The widespread extent of this disturbance presents a major challenge for governments and resource managers who must respond to the changes, yet lack a predictive understanding of how these systems will respond to the disturbance over various temporal and spatial scales. This disturbance allows us to test emerging theories of direct and indirect effects of vegetation change on coupled biogeochemical cycles following a disturbance that initially changes only the amount of living biomass while leaving soil hydrologic and chemical characteristics unchanged. By working at sites with different levels of MPB impact, we are evaluating how the dramatic loss of tree function both directly (i.e. transpiration and carbon fixation) and indirectly (i.e. snow capture, redistribution, and surface energy balance) affects water, carbon and nitrogen cycling. Our work is organized around two, broad questions that require both an interdisciplinary approach and close integration of observation and modeling. How do changes in vegetation structure associated with MPB alter the partitioning of energy and water? And How do these changes in energy and water availability affect local to regional scale biogeochemical cycles? We have assembled a diverse team of biogeochemists, ecologists, hydrologists, and atmospheric scientists to address these questions using measurements, modeling tools, and conceptual approaches from each discipline. Our approach includes intensive, coordinated hydrological, biogeochemical, and ecological observations designed to quantify the internal coupling of water, carbon, and nutrient cycling, as well as how these processes are expressed in both land surface-atmosphere exchanges and catchment solute export. These observations are closely integrated with two process models, one from the landsurface community and one from the catchment community, to evaluate our current understanding of how vegetation change alters coupled cycles. To extend our work beyond the relatively short time-scale of our observations, we coordinate with several ongoing projects, including the Boulder Creek CZO and the Niwot Ridge LTER.By quantifying both the biological and physical controls that forest vegetation has on water and biogeochemical cycles, our project will both improve our basic understand of the coupling between water, energy, carbon, and nitrogen. Through coordination with land surface and catchment modeling communities we will incorporate this knowledge into the broader community. Our educational activities build on successful efforts at all institutions, while coordination with land and water resource managers will ensure our knowledge is transferred to the applied science community.