Is overfishing triggerng the die-off of New England salt marshes?

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。过度捕捞正在成为海洋生态系统及其提供的社会服务的完整性的最大威胁之一。虽然捕食者枯竭的后果越来越受到重视，包括海带森林和珊瑚礁在内的一些经过充分研究的沿海栖息地，过度捕捞对包括盐沼在内的其他宝贵海洋生态系统的风险仍然不确定和有争议。二十多年来，盐沼植被的死亡一直在西大西洋蔓延，威胁着沼泽地提供沿海环境的重要苗圃、营养过滤和风暴屏障生态系统服务。该项目的前提是，最近描述的马萨诸塞州科德角盐沼死亡是由本地草食蟹，芝麻网，这些死亡是一个广泛的和积极扩大的威胁附近的海岸海洋生态系统在整个周围地区。研究人员概述了一项研究计划，通过探索以下问题来检验以下一般假设：中上层海洋捕食者的过度捕捞正在使相马种群摆脱捕食者的控制，并引发食草动物驱动的死亡和美国东北部盐沼的退化：1）区域性捕食者的枯竭是否会通过将食草性相马种群从捕食者的控制中释放出来而导致美国东北部盐沼的死亡？将对螃蟹和捕食者丰度以及沼泽死亡进行大规模区域调查，并对捕食压力和螃蟹食草性进行实验分析。2)当地的捕鱼压力是否引发并加剧了盐沼的死亡？在大量捕捞和附近的海洋保护区的捕食和食草动物的影响将被量化，探索初步数据表明当地的捕捞压力，螃蟹食草动物的压力和小溪银行死亡之间的因果关系。3)溪岸死亡如何影响美国东北部盐沼的结构及其提供生态系统服务的能力？研究人员将绘制并跟踪整个地区的死亡命运，以预测螃蟹死亡的个体发育和轨迹及其对盐沼提供的生态系统服务的影响。这项工作具有保护意义，因为它将捕食者的管理联系起来（商业和娱乐收获的螃蟹和鱼），可能会控制沼泽植物消费者与沿海湿地的健康和长期持久性，并将提供对这些系统的机械理解，这些系统是管理和持续提供生态系统服务所必需的。该研究将由一个强大的本科和研究生教育重点和社区外展组成部分的补充。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Overfishing is emerging as one of the greatest threats to the integrity of marine ecosystems and the societal services they provide. Though the consequences of predator depletion are increasingly appreciated for a few well-studied coastal habitats including kelp forests and coral reefs, the risks of overfishing to other valuable marine ecosystems including salt marshes remain uncertain and controversial. For over two decades, die-offs of salt marsh vegetation have been spreading across the Western Atlantic, threatening the critical nursery ground, nutrient filtering and storm barrier ecosystem services that marshes provide coastal environments. This project is based on the premise that recently described salt marsh die-offs on Cape Cod, Massachusetts are being driven by the native herbivorous crab, Sesarma reticulatum, and that these die-offs are an extensive and actively expanding threat to the near shore marine ecosystems throughout the surrounding region. The investigators outline a research program to examine the general hypothesis that overfishing of pelagic marine predators is releasing Sesarma populations from predator control and triggering herbivore-driven die-off and the degradation of Northeastern US salt marshes by exploring the following questions: 1) Is regional depletion of predators causing the die-off of Northeastern US salt marshes by releasing herbivorous Sesarma populations from predator control? Large-scale, regional surveys of crab and predator abundance and marsh die-off and experimental assays of predation pressure and crab herbivory will be conducted. 2) Is local fishing pressure triggering and intensifying salt marsh die-off? Impacts of predation and herbivory in heavily fished and nearby marine conservation areas will be quantified to explore preliminary data suggesting a strong causal relationship between local fishing pressure, crab herbivore pressure and creek bank die-off. 3) How are creek bank die-offs influencing the structure of Northeastern US salt marshes and their ability to provide ecosystem services? The investigators will map and follow the fate of die-offs throughout the region to develop a predictive understanding of the ontogeny and trajectory of crab-driven die-offs and their effect on the ecosystem services provided by salt marshes.This work has conservation implications since it links the management of predators (commercially and recreationally harvested crabs and fish) that may control marsh plant consumers with the health and long-term persistence of coastal wetlands, and will provide a mechanistic understanding of these systems necessary for their management and continued provision of ecosystem services. The research will be complemented by a strong undergraduate and graduate educational focus and a community outreach component.