Positive Effects of Coral Biodiversity on Coral Performance: Patterns, Processes, and Dynamics

珊瑚礁极其多样，提供关键的生态系统服务，并且正在以惊人的速度崩溃，近几十年来，加勒比海和太平洋的珊瑚分别减少了80%和50%。以前的研究强调负相互作用(竞争、捕食)是珊瑚礁系统的结构，但在这种物种丰富的系统中的正相互作用在维持生态系统功能方面可能具有同等重要的作用。如果珊瑚等基础物种依赖于积极的相互作用，那么它们的适合度可能会随着周围物种的丧失而下降，从而造成生物多样性的崩溃，其中一种珊瑚的丧失会导致其他珊瑚的丧失。该项目进行操纵性野外实验，以了解珊瑚生物多样性在促进珊瑚生长、生存、恢复和保留这些基础物种以及它们在热带浅海提供的关键生态系统服务方面所起的作用。该项目致力于：1)在沿海海洋系统失去生态功能和价值之前，就沿海海洋系统的保护和恢复对有影响力的商界和民间领袖进行教育和激励。这将使北乔治亚州/亚特兰大(美国东南部的主要经济引擎)内有影响力的扶轮社作为最初的重点。2)利用佐治亚理工学院的研究新闻和研究所通讯办公室以及与科学作家的良好联系，就这些研究中出现的重要海洋生态发现制作受欢迎的新闻报道。(3)组织了一次国际知名科学家公开讲习班，重点是将维持海洋生物多样性作为维持生态系统服务以及沿海文化和经济的战略。此前，调查人员组织了一次类似的活动，吸引了大约200人参加，并向佐治亚州的许多高中以及无法参加的欠发达国家的外国调查人员进行了网络直播。演讲者还对当地高中班级进行了面对面的视频采访。由于这一成功，这种模式将会重复。4)与法属波利尼西亚的教育工作者和文化领袖协会合作，制作关于我们的工作和珊瑚礁保护的电子格式演示文稿，适合波利尼西亚文化中的教师和领导人使用。生态学家擅长于证明物种对之间直接(通常是负面的)相互作用的重要性。然而，当这些相互作用发生在该领域数以千计的其他物种之间的复杂背景下时，许多鲜为人知的间接相互作用的总和可以抵消甚至逆转更知名的直接相互作用，产生扩散互惠而不是竞争的结果。在一项概念验证初步实验中，珊瑚混合养殖的珊瑚生长和存活率比单一养殖的珊瑚更大，特别是在群落发展的早期阶段。产生这一结果的过程尚不清楚，但随着珊瑚礁的多样性和功能的下降，以及人类需要预测和适应不断变化的环境，了解这些过程至关重要。这项跨学科的调查融合了试验田生态学、化学生态学和微生物生态学的专业知识，以调查生物多样性在珊瑚礁生态系统中的功能作用。实验使用一种新的珊瑚移植方法和野外操作来评估：1)更大的珊瑚物种多样性是否提高了珊瑚群落的表现，以及单个珊瑚的生长和存活，2)更大的基因多样性是否提高了物种内的珊瑚表现，3)更大的海藻竞争对手的多样性是否进一步抑制了珊瑚并提高了海藻的表现，以及4)驱动上述模式的过程，包括疾病的作用，种内和种间竞争，捕食者，互助者，以及对资源的差别获取或使用。这项研究调查了从物种到基因类型的珊瑚分类多样性各维度之间的生物多样性和生态系统功能之间的关系，并创建了一系列实验，阐明了生态系统动力学的一般原理。填补这些知识空白有助于我们从根本上理解生物多样性如何在多个尺度上影响生态系统的功能，并有助于洞察在这些物种丰富的生态系统中促进珊瑚共存的过程。这一发现将对珊瑚管理和恢复具有实际意义，并可能改善对珊瑚礁在面对气候变化时的弹性和恢复的预测。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。

Coral reefs are extremely diverse, supply critical ecosystem services, and are collapsing at an alarming rate, with 80% coral loss in the Caribbean and 50% in the Pacific in recent decades. Previous studies emphasized negative interactions (competition, predation) as structuring reef systems, but positive interactions in such species-rich systems could be of equal importance in maintaining ecosystem function. If foundation species like corals depend on positive interactions, then their fitness may decline with the loss of surrounding species, creating a biodiversity meltdown where loss of one coral causes losses of others. This project conducts manipulative field experiments to understand the role of coral biodiversity in facilitating coral growth, survival, resilience, and retention of these foundation species and the critical ecosystem services they provide in shallow tropical seas. This project is committed to: 1) Educating and exciting influential business and civic leaders about conservation and restoration of coastal marine systems before these systems lose ecological function and value. This will involve influential Rotary clubs within North Georgia/Atlanta (the major economic engine of the southeastern US) as an initial focus. 2) Using the Research News and Institute Communications Office at Georgia Tech and well-developed contacts with science writers to produce popular press pieces on important ocean ecology discoveries emerging from these studies. (3) Organizing a public workshop of internationally prominent scientists focused on Maintaining Marine Biodiversity as a Strategy to Sustain Ecosystem Services and Coastal Cultures and Economies. A previous effort like this, organized by the investigators, attracted about 200 attendees and was webcast to numerous high schools in Georgia and to foreign investigators in less developed countries that could not attend. Speakers also conducted in-person video interviews with local high school classes. Due to that success, this model will be repeated. 4) Working with an association of educators and cultural leaders in French Polynesia to produce electronic format presentations on our work and on reef conservation that are appropriate for use by both teachers and leaders within Polynesian culture. Ecologists have excelled at demonstrating the importance of direct (often negative) interactions among species pairs. However, when these interactions occur in a complex context among thousands of other species in the field, the sum of the many, poorly-known, indirect interactions can counterbalance, or even reverse, the better-known direct interactions, generating diffuse mutualisms instead of agonistic outcomes. In a proof-of-concept initial experiment, coral growth and survivorship were greater in coral polycultures than monocultures, especially during early stages of community development. Processes generating this outcome are unclear but understanding these is of critical importance as diversity and function of reefs decline and as humans need to predict and adapt to changing environments. This interdisciplinary investigation merges expertise in experimental field ecology, chemical ecology, and the ecology of microbiomes to investigate the functional role of biodiversity in coral reef ecosystems. Experiments use a novel coral transplantation method and field manipulations to assess: 1) whether greater coral species diversity enhances coral community performance, as well as growth and survivorship of individual corals, 2) whether greater genotypic diversity enhances coral performance within a species, 3) whether greater diversity of seaweed competitors further suppresses corals and enhances seaweed performance, and 4) the processes driving the patterns documented above, including the roles of disease, intraspecific versus interspecific competition, predators, mutualists, and differential access to, or use of, resources. The research investigates the relationship between biodiversity and ecosystem function across dimensions of coral taxonomic diversity, from species to genotypes, and creates a series of experiments elucidating general principles underlying ecosystem dynamics. Filling these knowledge gaps advances our fundamental understanding of how biodiversity influences ecosystem function at multiple scales and provides insight into the processes promoting coral coexistence in these species-rich ecosystems. Findings will have practical implications for coral management and restoration and may improve predictions regarding coral reef resilience and recovery in the face of changing climate.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.