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

珊瑚礁的多样性和独特的功能作用早已得到公认，但几十年来的干扰破坏了这些功能，使人们对它们的生存能力产生了怀疑。在此背景下，2017年加勒比地区发生了两次前所未有的飓风，这两次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少数受保护的珊瑚礁的影响特别不幸，但它也为了解几十年来一直在详细研究的珊瑚礁的影响创造了独特的机会。该项目利用了31年的珊瑚礁监测研究，其中大部分得到了NSF的支持，以描述飓风Irma和Maria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放弃的结论，但仍然未知的是，当今的珊瑚礁将如何应对众所周知的干扰（飓风）的严重版本，以及这些影响将如何影响它们的长期生存。将利用风暴后调查和新的分析来确定珊瑚丰度的持续下降是否影响了珊瑚礁应对风暴的方式，特别是增加了风暴后的死亡率，并降低了从这种事件中恢复的能力。为了实现这些成果，来自加州北岭州立大学的一个研究团队将利用R/V Walton Smith号游轮，利用摄影和水中计数来调查圣约翰的珊瑚礁，以生成将在2018年全年进行分析的数据。这项研究的好处将不仅限于科学发现，还包括为参加航行的其他科学家提供杠杆式支助，评价VI国家公园的自然资源状况，从迈阿密向圣约翰运送救济物资，以及为将参加项目所有阶段的研究生创造独特的研究和培训机会。 自20世纪50年代首次被描述以来，珊瑚礁的群落结构发生了巨大变化，目前温度上升，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人类世的持久性产生了怀疑。随着这种深刻的变化正在进行中，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，两个5级飓风的影响突出说明了为什么时间序列很重要，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，它们为检验有关扰动影响和后果的假设创造了背景。该项目解决了飓风Irma和Maria对美属维尔京群岛圣约翰珊瑚礁的影响，自20世纪50年代以来一直在研究，过去31年主要是在NSF LTREB的支持下。这一支持提供了重要珊瑚Orbicella annularis的种群动态以及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将表明，大浪杀死珊瑚，但这里的知识价值是通过检验一般假设获得的：（1）风暴对O。annularis将依赖于群体密度;（2）与以前的风暴相比，延迟的珊瑚死亡率将加剧;（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）进化拯救将通过大的初始种群规模、依赖密度的种群增长和补充来调解选定珊瑚礁的恢复。这些假设将通过R/V Walton Smith进行为期14天的巡航来进行测试，以收集关键的时间敏感数据，然后对新的和遗留的摄影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.