Collaborative Research: Pattern and process in the abundance and recruitment of Caribbean octocorals

珊瑚礁受到各种自然和人为干扰，生态系统退化的后果已被广泛宣传。然而，报告的变化偏向于鱼类和石珊瑚，对于加勒比珊瑚礁，这种偏见最显著的例子是八爪珊瑚（“软珊瑚”）。虽然它们数量丰富，在许多加勒比珊瑚礁中占主导地位，但由于难以识别和量化它们的丰度，它们很少被纳入研究。在一些地方，有令人信服的证据表明，软珊瑚的数量增加了，即使石珊瑚变得不那么常见。这表明软珊瑚比石珊瑚更能适应影响珊瑚的各种干扰。研究这些变化的最佳珊瑚礁是那些已经被研究了几十年的珊瑚礁，可以为最近的事件提供十年的背景，在这方面，美属维尔京群岛圣约翰的珊瑚礁是独一无二的。珊瑚礁上的石珊瑚从1987年开始研究，软珊瑚从2014年开始研究。这为评估八珊瑚的丰度和招募模式提供了无与伦比的平台；确定这些珊瑚礁上正在发生的变化模式，并确定造成八珊瑚种群恢复力的过程。该项目将把软珊瑚的监测时间由4年延长至8年，并在此框架内研究幼珊瑚的作用，以及它们对海底粗糙度、海水流动和海藻的反应，以确定软珊瑚的成功与否。这项工作还将评估飓风“厄玛”和“玛丽亚”的破坏性影响是否改变了变化的模式。为了配合这些努力，该项目将与当地高中紧密结合，调查人员将在那里举办海洋生物学俱乐部，并为学生和教师提供独立学习的机会。将为本科生和研究生以及一名博士后研究员提供独特的培训机会，所有这些人都将在圣约翰学习和工作，调查人员将通过在佛罗里达群岛举行的实践研讨会，培训珊瑚礁研究人员识别软珊瑚的种类。了解不断变化的环境条件将如何影响主要生物群系的群落结构是定义21世纪的生态学目标。这些条件对珊瑚礁的整体影响将在美属维尔京群岛圣约翰的维尔京群岛国家公园的浅层珊瑚礁上进行研究，这是该地区珊瑚礁群落动态的长期研究中运行时间最长的研究之一。在NSF-LTREB的支持下，自1987年以来，研究人员一直在研究该地区石珊瑚群落的长期变化，2014年，NSF-OCE的支持被用来建立一个十年期珊瑚“覆盖”。目前的项目从这段被飓风厄玛和玛丽亚打断的独特历史中延伸出来，将十月珊瑚的协同作用置于十年的背景下，研究人员利用丰富的遗留数据来更好地了解加勒比珊瑚礁的现在和不久的将来。这个为期四年的项目将同时在两个方面推进：第一，将八珊瑚群落的时间序列分析从4年延长到8年，以表征群落结构变化的模式和速度；第二，开展一个以八珊瑚定居为重点的假设驱动实验项目，该实验将揭示八珊瑚比现今珊瑚礁上的核状珊瑚更有效地定居底层的机制。具体而言，研究人员将针对以下四个假设进行测量和操作实验：(1)生境复杂性在区分八珊瑚和硬珊瑚招募生态位方面的作用；(2)招募生态位在调节定居后成功方面的作用；(3)海藻草皮和大型藻类的竞争在决定八珊瑚和硬珊瑚招募成功方面的作用；(4)八珊瑚冠层在调节颗粒和幼虫到海底的通量方面的作用。这项研究的结果将被综合起来，以评估在当今的加勒比珊瑚礁上，推动八爪珊瑚与硬核珊瑚具有更高生态恢复力的因素。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 exposed to a diversity of natural and anthropogenic disturbances, and the consequences for ecosystem degradation have been widely publicized. However, the reported changes have been biased towards fishes and stony corals, and for Caribbean reefs, the most notable example of this bias are octocorals ("soft corals"). Although they are abundant and dominate many Caribbean reefs, they are rarely included in studies due to the difficulty of both identifying them and in quantifying their abundances. In some places there is compelling evidence that soft corals have increased in abundance, even while stony corals have become less common. This suggests that soft corals are more resilient than stony corals to the wide diversity of disturbances that have been impacting coral corals. The best coral reefs on which to study these changes are those that have been studied for decades and can provide a decadal context to more recent events, and in this regard the reefs of St. John, US Virgin Islands are unique. Stony corals on the reefs have been studied since 1987, and the soft corals from 2014. This provides unrivalled platform to evaluate patterns of octocoral abundance and recruitment; identify the patterns of change that are occurring on these reefs, and identify the processes responsible for the resilience of octocoral populations. The project will extend soft coral monitoring from 4 years to 8 years, and within this framework will examine the roles of baby corals, and their response to seafloor roughness, seawater flow, and seaweed, in determining the success of soft corals. The work will also assess whether the destructive effects of Hurricanes Irma and Maria have modified the pattern of change. In concert with these efforts the project will be closely integrated with local high schools at which the investigators will host marine biology clubs and provide independent study opportunities for their students and teachers. Unique training opportunities will be provided to undergraduate and graduate students, as well as a postdoctoral researcher, all of whom will study and work in St. John, and the investigators will train coral reef researchers to identify the species of soft corals through a hands-on workshop to be conducted in the Florida Keys.Understanding how changing environmental conditions will affect the community structure of major biomes is the ecological objective defining the 21st century. The holistic effects of these conditions on coral reefs will be studied on shallow reefs within the Virgin Islands National Park in St. John, US Virgin Islands, which is the site of one of the longest-running, long-term studies of coral reef community dynamics in the region. With NSF-LTREB support, the investigators have been studying long-term changes in stony coral communities in this location since 1987, and in 2014 NSF-OCE support was used to build an octocoral "overlay" to this decadal perspective. The present project extends from this unique history, which has been punctuated by the effects of Hurricanes Irma and Maria, to place octocoral synecology in a decadal context, and the investigators exploit a rich suite of legacy data to better understand the present and immediate future of Caribbean coral reefs. This four-year project will advance on two concurrent fronts: first, to extend time-series analyses of octocoral communities from four to eight years to characterize the pattern and pace of change in community structure, and second, to conduct a program of hypothesis-driven experiments focused on octocoral settlement that will uncover the mechanisms allowing octocorals to more effectively colonize substrata than scleractinian corals on present day reefs. Specifically, the investigators will conduct mensurative and manipulative experiments addressing four hypotheses focusing on the roles of: (1) habitat complexity in distinguishing between octocoral and scleractinian recruitment niches, (2) the recruitment niche in mediating post-settlement success, (3) competition in algal turf and macroalgae in determining the success of octocoral and scleractian recruits, and (4) role of octocoral canopies in modulating the flux of particles and larvae to the seafloor beneath. The results of this study will be integrated to evaluate the factors driving higher ecological resilience of octocorals versus scleractinians on present-day Caribbean reefs.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.