RAPID: Hurricane Irma: Effects of repeated severe storms on shallow Caribbean reefs and their changing ecological resilience

长期以来，珊瑚礁因其多样性和独特的功能角色而受到认可，但这些特征已被数十年的干扰所破坏，使人们对其生存能力产生怀疑。在这种背景下，2017年加勒比地区遭遇了两场前所未有的飓风，这两场飓风都破坏了与几十年前相比已经退化的珊瑚礁。虽然这些风暴对美国国家公园和国家纪念碑系统内受保护的少数珊瑚礁的影响特别不幸，但它也为了解对珊瑚礁的影响创造了独特的机会，这些影响已经被详细研究了几十年。该项目利用这些机会，利用31年的珊瑚礁监测研究，其中大部分得到了美国国家科学基金会的支持，来描述飓风厄玛和玛丽亚对美属维尔京群岛圣约翰珊瑚礁的影响。分析将揭示严重的破坏是一个不可避免的结论，但仍然未知的是，今天的珊瑚礁将如何应对众所周知的严重干扰（飓风），以及这些影响将如何影响它们的长期生存。将使用风暴后调查和新的分析来确定珊瑚数量的持续减少是否影响了珊瑚礁对风暴的反应方式，特别是增加了风暴后死亡率，并降低了从这种事件中恢复的能力。为了实现这些结果，来自北岭加州州立大学的一组研究人员将乘坐R/V沃尔顿史密斯号游轮对圣约翰的珊瑚礁进行调查，使用摄影和水中计数来生成数据，这些数据将在2018年全年进行分析。这项研究的好处将超出科学发现的范围，包括为参与巡航的其他科学家提供支持，评估第六国家公园的自然资源状况，从迈阿密到圣约翰的救援物资运送，以及为参与项目所有阶段的研究生创造独特的研究和培训机会。自从20世纪50年代首次对珊瑚礁进行描述以来，它们的群落结构经历了巨大的变化，而目前来自气温上升、海水pH值下降、风暴和许多其他事件的威胁，使人们对它们在anthropo世的持久性产生了怀疑。随着这种深刻的变化，群落结构的时间序列分析是当代珊瑚礁研究的前沿。在加勒比地区，两次5级飓风的影响突出了时间序列的重要性，因为它们是描述这类事件影响的唯一手段，而且至关重要的是，它们为检验关于扰动影响和后果的假设创造了背景。该项目研究了飓风Irma和Maria对美属维尔京群岛圣约翰珊瑚礁的影响，该研究自20世纪50年代以来一直在研究，过去31年来主要得到了NSF LTREB的支持。该支持提供了重要珊瑚环轮虫种群动态和邻近生境珊瑚群落动态的描述。对这些风暴影响的任何研究都会证明大浪会杀死珊瑚，但这里的知识价值是通过对一般假设的测试获得的：(1)风暴对O. annularis的影响是依赖于种群密度的；(2)与之前的风暴相比，延迟珊瑚死亡率将会加剧；(3)自1989年以来，珊瑚群落对物理干扰的恢复能力有所下降；(4)进化救援将通过大的初始种群规模、依赖于密度的种群增长和招募来调解精选珊瑚的珊瑚礁恢复。这些假设将在沃尔顿·史密斯号上进行为期14天的巡航，收集关键的时间敏感数据，然后对新的和遗留的照片数据进行为期一年的分析。

Coral reefs have long been recognized for their diversity, and unique functional roles, but these features have been undermined by decades of disturbances that cast doubt on their ability to survive. Against this backdrop, 2017 brought two hurricanes of unprecedented magnitude to the Caribbean, both of which damaged coral reefs that already were degraded compared to those of a few decades ago. While the impacts of these storms on some of the few coral reefs protected within the US National Park and National Monument systems is particularly unfortunate, it also creates unique opportunities to understand the impacts on coral reefs that have been studied in detail for decades. This project builds on these opportunities by leveraging 31 years of coral reef monitoring research, much of which has been supported by NSF, to describe the impacts of Hurricanes Irma and Maria on coral reefs in St. John, US Virgin Islands. That the analyses will reveal severe destruction is a forgone conclusion, but what remains unknown is how present-day reefs will respond to severe versions of a well-known disturbance (hurricanes), and how these effects will impact their long-term survival. Post-storm surveys and new analyses will be used to determine whether ongoing declines in coral abundance have influenced the way coral reefs respond to storms, notably to enhance post-storm mortality, and reduce the capacity to recover from such event. To achieve these outcomes, a team of researchers from California State University, Northridge, will use a cruise on the R/V Walton Smith to survey the reefs of St. John using photography and in-water counts to generate data that will be analyzed throughout 2018. The benefits of this research will extend beyond scientific discoveries to include leveraged support for other scientists participating in the cruise, evaluation of the status of natural resources in the VI National Park, the delivery of relief supplies from Miami to St. John, and the creation of unique research and training opportunities for graduate students who will participate in all phases of the project. Coral reefs have undergone dramatic changes in community structure since they were first described in the 1950's, and the current onslaught of threats from rising temperature, declining seawater pH, storms, and numerous other events has cast doubt on their persistence in the Athropocene. With such profound changes underway, time-series analyses of community structure are on the cutting edge of contemporary studies of coral reefs. In the Caribbean, the impact of two category 5 hurricanes underscores why time-series are important, as they are the only means to describe the impact of such events, and critically, create the context for testing hypotheses regarding impacts and consequences of disturbances. This project addresses the impacts of Hurricanes Irma and Maria on the coral reefs of St. John, US Virgin Islands, which have been studied since the 1950's, and for the last 31 years largely with NSF LTREB support. This support provides descriptions of the population dynamics of the important coral, Orbicella annularis, and the coral community dynamics in adjacent habitats. Any study of the effects of these storms will demonstrate that large waves kill corals, but here intellectual merit is acquired through testing of general hypotheses: (1) storm impacts on O. annularis will be colony-density dependent, (2) delayed coral mortality will be accentuated compared to previous storms, (3) the resilience of coral communities to physical disturbances has declined since 1989, and (4) evolutionary rescue will mediate reef recovery for select corals through large initial population sizes, density-dependent population growth, and recruitment. These hypotheses will be tested using a 14 day cruise on the R/V Walton Smith to collect critical time-sensitive data, followed by a year of analysis of new and legacy photographic data.