RAPID: COLLABORATIVE RESEARCH: Mechanisms of seagrass community injury and resilience post Hurricane Florence: implications for increasingly stormy coasts

快速：合作研究：佛罗伦萨飓风后海草群落损伤和恢复力的机制：对日益暴风雨海岸的影响

• 批准号: 1906651
• 负责人: Fredrick Fodrie
• 金额: $ 8.25万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-02-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1906651&HistoricalAwards=false
• 关键词: RAPID; COLLABORATIVE; RESEARCH; Mechanisms; seagrass

Seagrass meadows are conspicuous features of many estuarine and nearshore environments. By some estimates, these meadows contribute an average of $20,000 per hectare per year in goods and services. These include nutrient cycling, sediment stabilization, carbon burial, and provision of nursery habitat for juvenile fishes, crabs, and shrimps. Alarmingly, seagrasses are threatened by several environmental and human-driven stressors, and loss of seagrass habitat remains a key concern for conservation and sustainable development programs. Anticipated increases in storminess (frequency and intensity) and rainfall under many climate change modeling scenarios make understanding hurricane impacts on valuable coastal habitats such as seagrass meadows important on local, national, and global scales. Indeed, seagrass meadows potentially serve as a 'canary in the coal mine' regarding the effects of increased hurricane activity as they are found at shallow depths and are affected by turbidity and salinity; seagrasses are also vulnerable to burial or erosion due to large storms. Seagrasses (1) include a suite of species with distinct growth and reproductive strategies; (2) live in a range of meadow sizes and degrees of 'patchiness;' and (3) present divergent seasonal cycles. This represents a tremendous opportunity to explore the conditions and attributes that result in seagrass resilience or vulnerability to hurricanes as a model for coastal ecosystem responses more broadly. Hurricane Florence made landfall along the NC coast on September 14, 2018. Florence stalled approaching shore, and storm-related winds/rains persisted for 4 days (13th-16th) in southeastern NC. Subsequently, record high sea-level stands (surge + tide) were observed across the NC coastline. Furthermore, Florence became the second wettest US storm, behind only Harvey in 2017, dumping 65 trillion L of rain over land that depressed estuarine salinities for over a month. NC seagrasses are dominated by three species: eelgrass, shoalgrass, and widgeon grass. Meadows exist as polycultures or monocultures, and exhibit a diverse range of spatial configurations. Meadows are also defined by strong seasonality: eelgrass shoots senesce in summer due to heat stress, with sites transformed either into shoalgrass-dominated meadows or mudflats. Subsequent to dieback, eelgrass depends upon a combination of seedbank and surviving apical meristems for regeneration each winter. Using key seagrass datasets collected by the research team dating back decades across ~40 Florence-impacted meadows, several fundamental ecological questions are being addressed: (1) how sexual (eelgrass: seedbank) v. asexual (shoalgrass: vegetative growth and fragment colonization) life histories promote susceptibility or resilience of seagrass to disturbance; (2) how meadow landscape configuration and plant diversity modulate the effect of storms on seedbank retention; (3) how meadow disturbance (intense physical v. more chronic physiochemical drivers) affected community dynamics, with special focus on plant productivity and the critical 'nursery role' of seagrass habitat; and (4) how seasonality and species traits amplify or attenuate the effects of intense disturbance on seagrasses. This research expands upon previous post-hurricane studies by considering the interactive effects of hurricanes, landscape configuration, and biodiversity on ecosystem responses. It also leverages ongoing, NSF-supported work along the TX coast to compare-and-contrast the responses of different seagrass phenology/growth strategies to storm disturbance (e.g., turtlegrass in TX is a "leaf-on" species throughout the year while eelgrass and shoalgrass in NC both exhibit strong seasonality in biomass). Collectively, this work will result in more generalizable models of coastal ecological resilience to storminess.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.

海草草甸是许多河口和近岸环境的显著特征。据估计，这些草地每年平均为每公顷土地贡献2万美元的商品和服务。这些措施包括营养循环、沉积物稳定、碳掩埋以及为幼鱼、蟹和虾提供育苗栖息地。令人担忧的是，海草受到几种环境和人类驱动的压力的威胁，海草栖息地的丧失仍然是保护和可持续发展计划的关键问题。在许多气候变化模拟情景下，暴风雨(频率和强度)和降雨量的预期增加使得了解飓风对宝贵的沿海生境(如海草草地)的影响在地方、国家和全球范围内具有重要意义。事实上，海草草甸在飓风活动增加的影响方面有可能成为煤矿中的金丝雀，因为它们位于较浅的深处，受到浑浊和盐度的影响；海草也容易被掩埋或因大风暴而受到侵蚀。海草(1)包括一组具有不同生长和繁殖策略的物种；(2)生活在不同大小和斑块程度的草甸中；(3)呈现不同的季节周期。这是一个极大的机会，可以探索导致海草抗飓风能力或脆弱性的条件和属性，作为更广泛的沿海生态系统反应的模式。2018年9月14日，飓风佛罗伦萨在北卡罗来纳州沿海登陆。佛罗伦萨停滞不前，与风暴有关的风/雨在北卡罗来纳州东南部持续了4天(13日至16日)。随后，在北卡罗来纳州的海岸线上观察到了创纪录的高海平面(潮汐+潮汐)。此外，佛罗伦萨成为美国第二潮湿的风暴，仅次于2017年的哈维，给陆地带来了65万亿L的降雨，导致河口盐碱度下降了一个多月。北卡罗来纳州的海草主要由三种植物组成：鳗草、滩草和鹰嘴草。草甸以多元文化或单一文化的形式存在，并展示了各种不同的空间形态。草甸也有很强的季节性：夏季，由于热胁迫，鳗草的嫩枝会衰老，草场要么变成以滩涂为主的草甸，要么变成泥滩。在枯萎之后，鳗草依靠种子库和幸存的顶端分生组织的组合在每年冬天再生。利用研究小组几十年前在40个受佛罗伦萨影响的草甸上收集的关键海草数据集，正在解决几个基本的生态学问题：(1)有性(鳗草：种子库)和无性(草本植物：营养生长和碎片定居)生活史如何促进海草对干扰的敏感性或弹性；(2)草甸景观配置和植物多样性如何调节风暴对种子库保留的影响；(3)草甸干扰(强烈的物理和更长期的生理驱动因素)如何影响群落动态，特别是植物生产力和海草栖息地的关键‘苗圃作用’；以及(4)季节性和物种特征如何放大或减弱强烈干扰对海草的影响。这项研究通过考虑飓风、景观配置和生物多样性对生态系统响应的交互影响，扩展了以前的飓风后研究。它还利用德克萨斯州海岸正在进行的、由NSF支持的工作来比较和对比不同海草物候/生长策略对风暴干扰的反应(例如，德克萨斯州的龟草全年都是“叶上”物种，而北卡罗来纳州的鳗草和滨草都表现出很强的季节性生物量)。总的来说，这项工作将产生更普遍的海岸生态抗风暴能力模型。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。