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，即障碍岛、潮间带沼泽和带有海草的泻湖，可以减少风暴的侵蚀，抑制风和海浪，并吸收洪水。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提供了好处，包括支持渔业、娱乐、旅游业和碳封存。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)。这些转变发生在数年到数十年的时间尺度上，并影响到沿海生态系统的效益。辽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。它为理解沿海长期变化的动态提供了独特的背景。这一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。在栖息地碎片化和人类活动破坏自然联系的其他区域，这种联系很少发生。在预测沿海系统对重大环境变化的长期反应方面，了解这些生态系统的个别转变，以及变化如何通过相互关联的动态在整个景观中传播，是一个关键的前沿。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。这些数据促进了能够预测景观水平变化及其生态后果的机械模型的开发和测试。由于世界上一半以上的人口居住在距离海岸100公里的范围内，更多的人依赖沿海资源，这些地区的生态系统变化对沿海的复原力具有重要影响。VCR LTER计划通过与管理机构和自然保护协会的合作，为海岸管理、恢复和保护提供信息，以提高海岸对环境变化的适应能力。它对弗吉尼亚州教师的培训以及教育和宣传材料的开发做出了广泛的贡献，这些材料可以接触到全国和国际受众。最后，支持本科生、研究生和博士后研究员的研究培训。该计划与大西洋沿岸的其他LTER站点建立了网络，为管理人员、教师和学生提供了关于东海岸的更广阔的视角。VCR研究通过对驱动生态系统状态变化动态的生态和物理(地貌、水文)过程的综合研究来促进这一理解。变化可能是线性的，也可能涉及导致突然、非线性过渡到不同生态状态的阈值(临界点)。处理景观组成部分的复杂性和相互依存性对于实现对沿海动态的全面了解至关重要，并将推动关于生态系统状态变化和复原力的一般理论。VCR的研究活动围绕四个相关的主题问题组织：(1)长期变化的驱动因素和模式：生态系统的分布、空间范围和特征随着时间的推移如何变化，这些变化与气候趋势和变异性有何关系？(2)景观单元内的动力学：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)景观单元之间的动力学：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提供栖息地，作为与重要的沿海生态系统服务相联系的两项功能。总而言之，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。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.