LTER: Climate drivers, dynamics, and consequences of ecosystem state change in coastal barrier systems

弗吉尼亚海岸保护区（VCR）长期生态研究项目致力于发展对海岸屏障系统动态景观的预测性理解。健康的沿海生态系统是抵御海平面上升和风暴的第一道防线。这些系统的关键组成部分，即堰洲岛、潮间带沼泽和有海草的泻湖，减少了风暴的侵蚀，抑制了风和波，并吸收了洪水。因此，沿海生态系统保护沿海社区。此外，这些生态系统还为社会带来益处，包括支持渔业、娱乐、旅游和碳封存。海平面上升、风暴和极端温度导致景观成分之间的转变（例如，从高地到沼泽、从裸露到以海草为主的泻湖的变化）。这些转变发生在几年到几十年的时间尺度上，并影响沿海生态系统的效益。广阔的弗吉尼亚海岸保护区是美国大西洋沿岸最大的未开发海岸线。它提供了一个独特的环境来了解长期沿海变化的动态。这个模型系统使研究岛屿、泻湖、泥滩、沼泽和高地之间的联系成为可能。在生境破碎化和人类活动破坏自然联系的其他区域，很少能建立这种联系。单独了解这些生态系统的转变，以及变化如何通过相互关联的动态在景观中传播，是预测沿海系统对重大环境变化的长期响应的关键前沿。该项目将长期观测和实验数据与短期研究相结合，为生态系统动力学提供新的见解。这些数据促进了景观水平变化及其生态后果预测机制模型的发展和检验。世界上一半以上的人口生活在距离海岸100公里的范围内，更多的人口依赖沿海资源，这些地区的生态系统变化对沿海恢复能力产生了重要影响。VCR LTER计划通过与管理机构和大自然保护协会的合作，为海岸管理、恢复和保护提供信息，以增强海岸对环境变化的适应能力。它广泛地为培训弗吉尼亚的教师和编写教育材料和外联材料作出贡献，以达到国内和国际的受众。最后，支持本科生、研究生和博士后的研究培训。该项目与大西洋沿岸的其他LTER站点建立了网络，为管理人员、教师和学生提供了一个更大的关于东海岸的视角。VCR研究通过对驱动生态系统状态变化动力学的生态和物理（地貌、水文）过程的综合研究推进了这一认识。变化可能是线性的，也可能涉及阈值（引爆点），导致一个突然的、非线性的过渡到一个不同的生态状态。解决景观组成部分的复杂性和相互依赖性对于实现对沿海动态的整体理解至关重要，并将推进生态系统状态变化和恢复力的一般理论。VCR的研究活动围绕四个相关的主题问题展开：(1)长期变化的驱动因素和模式：生态系统的分布、空间范围和特征如何随时间变化，这些变化与气候趋势和变率之间的关系如何？(2)景观单元内的动态：生态和物理过程如何相互作用以维持生态系统状态或促进向新状态的过渡？(3)景观单元间动态：连通性如何影响生态系统状态变化？(4)状态变化的生态后果：生态系统状态变化对生态系统功能的影响是什么？VCR研究的重点是碳固存和生境供应，这两个功能与重要的沿海生态系统服务有关。总的来说，这项研究将增加我们对沿海生态系统及其功能如何在多个空间、时间和生态尺度上响应气候强迫的预测性理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Virginia Coast Reserve (VCR) Long Term Ecological Research project is dedicated to developing a predictive understanding of the dynamic landscapes of coastal barrier systems. Healthy coastal ecosystems are the first line of defense against sea-level rise and storms. Key components of those systems, i.e., barrier islands, intertidal marshes, and lagoons with seagrass, reduce erosion from storms, dampen wind and waves, and absorb flooding waters. Thus, coastal ecosystems protect coastal communities. In addition, these ecosystems provide benefits to society including support for fisheries, recreation, tourism, and sequestration of carbon. Sea-level rise, storms, and temperature extremes cause transitions among landscape components (e.g., changes between uplands to marsh, bare to seagrass-dominated lagoons). These transitions occur on time scales of years to many decades and influence the benefits of coastal ecosystems. The vast Virginia Coast Reserve is the greatest expanse of undeveloped coastline along the U.S. Atlantic seaboard. It provides a unique setting to understand the dynamics of long-term coastal change. This model system makes it possible to examine linkages among islands, lagoons, mudflats, marshes, and uplands. Such linkages can rarely be made in other regions where habitat fragmentation and human activities disrupt natural connections. Understanding these ecosystem transitions individually, and how changes propagate across the landscape through linked dynamics is a critical frontier in predicting the long-term response of coastal systems to significant environmental change. This project synthesizes long-term observations and experimental data with shorter-term studies to provide novel insights on ecosystem dynamics. These data promote the development and testing of mechanistic models that can predict landscape level change and its ecological consequences. With more than half the world's population living within 100 km of the coast, and even more depending on coastal resources, ecosystem changes in these regions have important consequences for coastal resilience. The VCR LTER program informs coastal management, restoration, and conservation to enhance coastal resilience to environmental changes through partnerships with management agencies and The Nature Conservancy. It contributes extensively to the training of Virginia teachers and the development of educational and outreach materials that reach national and international audiences. Finally, it supports the research training of undergraduates, graduate students and postdoctoral fellows. The program networks with other LTER sites along the Atlantic coast to provide a larger perspective on the eastern seaboard to managers, teachers, and students.VCR research advances this understanding through integrated studies of the ecological and physical (geomorphic, hydrologic) processes that drive ecosystem state change dynamics. Changes may be linear, or they may involve thresholds (tipping points) that lead to an abrupt, non-linear transition to a different ecological state. Addressing the complexity and interdependence of landscape components is critical to achieving a holistic understanding of coastal dynamics and will advance general theory on ecosystem state change and resilience. Research activities at VCR are organized around four related thematic questions: (1) Drivers and Patterns of Long-term Change: How have the distribution, spatial extent, and characteristics of ecosystems changed over time and how are these changes related to climate trends and variability? (2) Dynamics within Landscape Units: How do ecological and physical processes interact to maintain ecosystem states or facilitate transitions to new ones? (3) Dynamics between Landscape Units: How does connectivity influence ecosystem state change? (4) Ecological Consequences of State Change: What are the consequences of ecosystem state change for ecosystem function? VCR research focuses on carbon sequestration and habitat provisioning as two functions that are linked to important coastal ecosystem services. Collectively, this research will increase our predictive understanding of how coastal ecosystems and their functions respond to climate forcing at multiple spatial, temporal, and ecological scales.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.