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

智力上的功绩。该项目将开发一个全球合作的实地实验网络，以量化资源和放牧如何交互影响生物多样性和非生物强迫中的自然梯度上的生物量、生产和营养转移。它侧重于无脊椎动物和全球分布的鳗草(Zostera Marina)之间的一种关键的互惠关系，作为一个模式系统，并作为世界各地重要但受到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的功能(BEF)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只关注自下而上的强迫，而这些无处不在的动物在野外的影响几乎是未知的。研究计划将解决三个问题：(1)甲壳类中尺度动物(相当于放牧的桡足类)在调节植被覆盖的海岸生态系统功能和富营养化的缓冲作用方面发挥了什么作用？(2)在复杂的开放海洋系统中，15年的BEF实验得出的结论与生态系统特性的变化是否一致？(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？方法将包括两种新的方法。首先，一项排除没有笼状人工制品的甲壳类中划虫的新技术将严格测试它们在培育大型植物优势方面长期被怀疑的作用。该项目汇集了经验丰富的合作者，他们将在横跨亚全球范围内的12个地点的每个地点进行相同的析因实验，操纵食草动物和养分负荷，跨越多样性和非生物强迫变量的伴随梯度。第二，结构方程模型(SEM)，专门用于量化复杂系统中变量之间的相对重要性和相互作用，将梳理出资源供应、牧草生物量、物种组成和丰富度以及几个非生物变量对鳗草和藻类生物量、产量和营养转移的影响。综合群落的小规模实验表明，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，多样性的重要性仍然知之甚少。有趣的是，在来自野生生态系统的少数研究中，BEF关系的饱和程度往往比实验中高得多，这表明先前的工作可能低估了而不是高估了多样性的功能影响。然而，几乎没有大规模的数据集可以用来评估这一猜测。这项研究将在全球范围内的鳗草床上进行，这是为数不多的可能进行此类测试的群落类型之一。该项目将启动一个持久的、开放的、合作的研究人员网络，研究多营养海洋植被生态系统的功能。它利用了分布在全球各地的丰富的合作者专业知识、人力和与跨国伙伴关系的经验，包括由澳大利亚研究理事会资助的新的海洋植物-草食生态学家网络；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，它将促进几项以前独立的研究努力的整合。该项目还将通过学生交流计划帮助建立下一代合作的海洋植被生态学家：来自每个合作伙伴地点的学生将全面参与其他地点之一的实验，提供新系统的实地经验，并培养与新同事的关系，这种关系将远远超过该奖项的任期。学生将从现有的霍尔-邦纳海洋科学少数族裔博士学者计划(VIMS是该计划的合作伙伴)以及其他几个培训海洋科学方面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.