Collaborative Research: Habitat fragmentation effects on seagrass fish diversity at landscape scales: experimental tests of multiple mechanisms

栖息地的数量和质量被认为对维持沿海海洋生态系统至关重要。这项研究将使用大规模的实地实验，以帮助了解鱼类种群如何以及为什么对海草栖息地的碎片化做出反应。这个问题是复杂的，因为海草床的碎片化程度增加，减少了数量，也减少了栖息地的配置（一个斑块分裂成许多斑块，斑块变得更远，边缘数量增加等）。研究人员以前在天然海草草甸中的工作提供了证据，表明碎片化与栖息地数量相互作用，影响沿海海洋景观中鱼类的群落动态。具体而言，破碎化没有影响时，栖息地是大的，但有负面影响时，栖息地是较小的。在这项研究中，研究人员将建立人工海草栖息地，用于一系列雄心勃勃的规模操纵实地实验。研究结果将提供新的，更具体的信息，沿海鱼类群落动态是如何影响海草栖息地的总量和碎片的变化，在音乐会的因素，如干扰，幼虫扩散，和波能。该项目将支持两名早期职业调查员，为沿海管理提供栖息地保护战略，并为研究生和本科生提供培训机会。调查人员计划将研究机会瞄准来自代表性不足群体的学生。基于先前在海草环境中的研究，这项研究将在新的，但相关的尺度上进行一系列的实地实验，以测试栖息地面积和破碎化如何影响鱼类多样性和生产力。具体而言，将使用人工海草单元（ASU）创建15 × 15米的海草床，控制斑块内（~1-10平方米）的因素，如枝条密度和长度。调查人员将利用ASU来控制北卡罗来纳州一个温带河口的总栖息地面积和海草床内的破碎程度。在第一年，这些景观中的鱼类的反应将被测量为丰度，生物量，群落结构，以及分类和功能多样性。然后，有针对性的ASU清除将确定物种对栖息地干扰的具体反应。在第二年，景观阵列和采样制度将增加一倍，一半的景观将与低扩散能力的后仔鱼播种，以测试是否前或后招聘过程驱动的规模模式。在第三年，波曝光（海草碎片化的自然驱动因素）在介导鱼类群落对景观配置的反应的作用将通过在低能量和高能量环境中部署ASU草地进行测试。

Amount and quality of habitat is thought to be of fundamental importance to maintaining coastal marine ecosystems. This research will use large-scale field experiments to help understand how and why fish populations respond to fragmentation of seagrass habitats. The question is complex because increased fragmentation in seagrass beds decreases the amount and also the configuration of the habitat (one patch splits into many, patches become further apart, the amount of edge increases, etc). Previous work by the investigators in natural seagrass meadows provided evidence that fragmentation interacts with amount of habitat to influence the community dynamics of fishes in coastal marine landscapes. Specifically, fragmentation had no effect when the habitat was large, but had a negative effect when habitat was smaller. In this study, the investigators will build artificial seagrass habitat to use in a series of manipulative field experiments at an ambitious scale. The results will provide new, more specific information about how coastal fish community dynamics are affected by changes in overall amount and fragmentation of seagrass habitat, in concert with factors such as disturbance, larval dispersal, and wave energy. The project will support two early-career investigators, inform habitat conservation strategies for coastal management, and provide training opportunities for graduate and undergraduate students. The investigators plan to target students from underrepresented groups for the research opportunities. Building on previous research in seagrass environments, this research will conduct a series of field experiments approach at novel, yet relevant scales, to test how habitat area and fragmentation affect fish diversity and productivity. Specifically, 15 by 15-m seagrass beds will be created using artificial seagrass units (ASUs) that control for within-patch-level (~1-10 m2) factors such as shoot density and length. The investigators will employ ASUs to manipulate total habitat area and the degree of fragmentation within seagrass beds in a temperate estuary in North Carolina. In year one, response of the fishes that colonize these landscapes will be measured as abundance, biomass, community structure, as well as taxonomic and functional diversity. Targeted ASU removals will then follow to determine species-specific responses to habitat disturbance. In year two, the landscape array and sampling regime will be doubled, and half of the landscapes will be seeded with post-larval fish of low dispersal ability to test whether pre- or post-recruitment processes drive landscape-scale patterns. In year three, the role of wave exposure (a natural driver of seagrass fragmentation) in mediating fish community response to landscape configuration will be tested by deploying ASU meadows across low and high energy environments.