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

珊瑚礁极其多样化，提供重要的生态系统服务，但正在以惊人的速度崩溃，近几十年来，加勒比地区的珊瑚损失了80%，太平洋地区的珊瑚损失了50%。以前的研究强调负相互作用（竞争，捕食）作为构建珊瑚礁系统，但在这种物种丰富的系统中，积极的相互作用对于维持生态系统功能同样重要。如果像珊瑚这样的基础物种依赖于积极的相互作用，那么它们的适应性可能会随着周围物种的消失而下降，从而造成生物多样性的崩溃，即一种珊瑚的消失导致其他珊瑚的消失。本项目通过可操作的野外实验，了解珊瑚生物多样性在促进这些基础物种的生长、生存、恢复力和保留方面的作用，以及它们在热带浅海中提供的关键生态系统服务。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，教育和激励有影响力的商业和公民领袖保护和恢复沿海海洋系统。这将涉及在北乔治亚/亚特兰大（美国东南部的主要经济引擎）有影响力的扶轮社作为最初的焦点。2)利用佐治亚理工学院的研究新闻和研究所通讯办公室，并与科学作家建立良好的联系，就这些研究中出现的重要海洋生态学发现撰写流行的新闻稿件。(3)组织一次由国际知名科学家参加的公共研讨会，主题为“维持海洋生物多样性作为维持生态系统服务和沿海文化与经济的战略”。之前由调查人员组织的类似活动吸引了大约200名与会者，并通过网络向格鲁吉亚的许多高中和无法参加的欠发达国家的外国调查人员进行了直播。演讲者还对当地高中班级进行了面对面的视频采访。由于这种成功，这种模式将被重复。4)与法属波利尼西亚的教育工作者和文化领袖协会合作，制作适合波利尼西亚文化中教师和领导者使用的关于我们的工作和珊瑚礁保护的电子格式演示文稿。生态学家擅长于证明物种对之间直接（通常是消极）相互作用的重要性。然而，当这些相互作用发生在一个复杂的背景下，在该领域的数千个其他物种中，许多鲜为人知的间接相互作用的总和可以抵消，甚至逆转，众所周知的直接相互作用，产生扩散的相互作用，而不是激动的结果。在一项概念验证的初步实验中，珊瑚复合栽培比单一栽培的珊瑚生长和存活率更高，特别是在群落发展的早期阶段。产生这种结果的过程尚不清楚，但随着珊瑚礁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。这项跨学科的研究融合了实验场生态学、化学生态学和微生物组生态学的专业知识，以研究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现场操作来评估：1)更大的珊瑚物种多样性是否会提高珊瑚群落的性能，以及单个珊瑚的生长和存活，2)更大的基因型多样性是否会提高一个物种内珊瑚的性能，3)更大的海藻竞争对手多样性是否会进一步抑制珊瑚并提高海藻的性能，以及4)驱动上述模式的过程，包括疾病的作用，种内与种间竞争，捕食者，共生者，以及对资源的不同获取和使用。从物种到基因型，研究了珊瑚分类多样性与生态系统功能之间的关系，并进行了一系列实验，阐明了生态系统动力学的一般原理。填补这些知识空白促进了我们对生物多样性如何在多个尺度上影响生态系统功能的基本理解，并提供了在这些物种丰富的生态系统中促进珊瑚共存的过程的见解。研究结果将对珊瑚的管理和恢复具有实际意义，并可能改进对面对气候变化的珊瑚礁复原力和恢复的预测。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.