Biodiversity and Complex Forcing of Ecosystem Functioning in the Marine Foundation Species, Eelgrass: A Global Experimental Network

智力优势。该项目将开发一个全球合作网络的实地实验，以量化资源和放牧如何相互影响生物量，生产，营养转移沿着自然梯度的生物多样性和非生物强迫。它侧重于无脊椎动物mesograzers和全球分布的鳗草（Zostera marina）之间的一个关键的互惠关系，作为一个模型系统，并作为全球重要但受威胁的沿海生态系统的基础。这种相互作用为将生物多样性与多营养生态系统功能联系起来的有影响力的实验提供了一个模型。然而，海草生态学在历史上几乎完全集中在自下而上的强迫，和这些无处不在的动物在外地的影响几乎是unknowed.The研究计划将解决三个问题：（1）什么样的作用，甲壳类中食动物，底栖食草桡足类，在调节植被海岸生态系统功能和缓冲富营养化的影响？(2)从15年的BEF实验中得出的结论是否与复杂开放海洋系统中生态系统特性沿着自然多样性梯度的变化一致？(3)资源供应、放牧压力和生物多样性对生态过程的相对影响和相互作用是否随气候和非生物环境驱动因素而系统地变化？方法将包括两个新的方法。首先，一种新的技术，排除甲壳类mesograzers没有笼子文物将严格测试其长期怀疑的作用，促进大型植物的优势。该项目汇集了经验丰富的合作者，他们将在12个地点进行相同的析因实验，在多样性和非生物强迫变量的伴随梯度中，在每个地点操纵食草动物和营养负荷。第二，结构方程模型（SEM），专门设计来量化复杂系统中变量之间的相对重要性和相互作用，将梳理除了资源供应，食草动物生物量，物种组成和丰富度，以及几个非生物变量的影响，对鳗草和藻类生物量，生产和营养转移。对综合群落进行的小规模实验表明，生物多样性通常会提高一系列生态系统的生产和资源利用，但相对于其他有充分记录的强迫因素，对多样性的重要性仍然知之甚少。有趣的是，BEF的关系在少数研究野生生态系统往往饱和在更高的丰富度比在实验中，这表明以前的工作可能低估，而不是高估多样性的功能效果。然而，很少有大规模的数据集可用于评估这一猜想。这项研究将在全球范围内对鳗草床进行研究，鳗草床是少数几个可以进行这种测试的群落类型之一。该项目将启动一个持久、开放、协作的研究人员网络，研究多营养海洋植被生态系统的功能。它利用了全球分布的合作者的丰富专业知识，人力资源和跨国合作伙伴关系的经验，包括由澳大利亚研究理事会资助的海洋植物-草食动物生态学家的新网络;海洋生物普查的NaGISA项目;以及MarBEF的BIOFUSE项目的主要合作伙伴。因此，它将促进几个以前独立的研究工作的整合。该项目还将通过学生交流计划帮助建立下一代合作海洋植被生态学家：来自每个合作伙伴网站的学生将充分参与其他网站之一的实验，提供新系统的实地经验，并培养与新同事的关系。学生将从现有的霍尔-邦纳海洋科学少数民族博士学者计划中招募，其中VIMS是合作伙伴，并从其他几个培训海洋科学代表性不足的群体的地方计划中招募。

Intellectual Merit. This project will develop a global collaborative network of field experiments to quantify how resources and grazing interactively affect biomass, production, and trophic transfer along natural gradients in biodiversity and abiotic forcing. It focuses on a key mutualism between invertebrate mesograzers and the globally distributed eelgrass (Zostera marina), as a model system and as the foundation of important but threatened coastal ecosystems worldwide. This interaction provided a model for influential experiments linking biodiversity to functioning (BEF) of multitrophic ecosystems. Yet, seagrass ecology has historically focused almost exclusively on bottom-up forcing, and impacts of these ubiquitous animals in the field are nearly unknown.The research program will address three questions: (1) What role do crustacean mesograzers, the benthic equivalents of grazing copepods, play in regulating vegetated coastal ecosystem functioning and buffering effects of eutrophication? (2) Are generalizations derived from 15 years of BEF experiments consistent with variation in ecosystem properties along natural diversity gradients in complex, open marine systems? (3) Do relative influences and interactions of resource supply, grazing pressure, and biodiversity on ecological processes vary systematically with climate and abiotic environmental drivers? Methods will include two novel approaches. First, a new technique that excludes crustacean mesograzers without cage artifacts will rigorously test their long-suspected role in fostering macrophyte dominance. The project assembles experienced collaborators who will conduct identical factorial experiments manipulating grazers and nutrient loading at each of 12 sites spanning the sub-global range of eelgrass, across concomitant gradients in diversity and abiotic forcing variables. Second, Structural Equation Models (SEM), designed specifically to quantify relative importance and interactions among variables in complex systems, will tease apart effects of resource supply, grazer biomass, species composition, and richness, and several abiotic variables on eelgrass and algal biomass, production, and trophic transfer. Small-scale experiments with synthesized communities show that biodiversity generally enhances production and resource use in a range of ecosystems, but the importance of diversity relative to other well-documented forcing factors remains poorly understood. Intriguingly, BEF relationships in the few studies from wild ecosystems often saturate at much higher richness than in experiments, suggesting that prior work may underestimate rather than overestimate functional effects of diversity. Yet few large-scale data sets are available to evaluate this conjecture. This research will do so on a global scale in eelgrass beds, one of the few community types in which such a test is possible.Broader Impacts. This project will initiate a lasting, and open, collaborative network of researchers studying the functioning of multitrophic marine vegetation ecosystems. It leverages a wealth of globally distributed collaborator expertise, person power, and experience with multinational partnerships including a new network of marine plant-herbivore ecologists funded by the Australian Research Council; the Census of Marine Life's NaGISA project; and key partners in MarBEF's BIOFUSE project. It will thus catalyze integration of several formerly independent research efforts. The project will also help establish the next generation of collaborative marine vegetation ecologists through a student exchange program: students from each partner site will participate fully in the experiment at one of the other sites, providing field experience in new systems, and fostering relationships with new colleagues lasting well beyond the tenure of this award. Students will be recruited from the existing Hall- Bonner Program for Minority Doctoral Scholars in Ocean Sciences, of which VIMS is a partner, and from several other local programs that train underrepresented groups in marine science.