An interdisciplinary approach to elucidating the causes of widespread mangrove die-off

阐明红树林广泛死亡原因的跨学科方法

• 批准号: 1541637
• 负责人: Craig Layman
• 金额: $ 7.52万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-15 至 2016-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1541637&HistoricalAwards=false
• 关键词: interdisciplinary; approach; elucidating; causes; widespread

Foundation species are those that form the basis for entire ecosystems, substantially altering the physical and biological characteristics of the areas in which they are found. Mangroves are one of the most conspicuous groups of foundation species, providing numerous ecosystems services which we highly value, e.g., habitat for ecologically and economically important species, shoreline stablilization and carbon storage. As such, global declines in mangroves is of upmost concern. For example, an extensive die-off of dwarf red mangrove has been identified in a remote area on the west side of Abaco Island, The Bahamas. Because of its remote nature of the site, the die-off is unlikely to be directly due to human activities. Despite its largely inaccessible nature, the area is ecologically and economically important, e.g., it is the primary bonefishing area on Abaco - an industry worth more than $150 million annually in The Bahamas. Therefore, it is of pressing concern for stakeholders in The Bahamas to identify the underlying cause(s) of decline and assess potential threat to mangroves in other areas. To do so, a series of activities will be carried out, included widespread surveys for a recently identified fungal pathogen, laboratory efforts to isolate and identify this pathogen, satellite imagery mapping activities, and simulated grazing experiments. The area in which the die-off is occurring is currently being considered for designation as a national park by the Bahamian National Trust (BNT). The results of the study will be directly communicated to the BNT and will be used to make immediate management decisions. In collaboration with two Bahamian environmental NGOs, Friends of the Environment and Bahamas Reef Environmental Education Foundation (BREEF), a citizen science-based survey for fungal lesions, as well as an educational module on mangrove ecology, will be designed. The data from the citizen-science and student surveys will be integrated in a map of the incidence of the lesions across The Bahamas. The citizen-science component, and interaction with bonefish guides, provides the opportunity to further integrate science and education. The educational module will be introduced at the BREEF summer teaching training workshop in July. This annual event typically includes 30 teachers from 10 islands. The investigators will continue to make all of our research findings immediately available and accessible to the public through the Abaco Scientist website (http://appliedecology.cals.ncsu.edu/absci/).Provisioning of ecosystem services in the coastal realm is largely mediated by foundation species, such as mangroves, coral and salt marsh grasses. Many of these species are undergoing substantial declines throughout the world. These declines are often driven by complex, interacting, stressors that may be difficult to identify and elucidate. Despite the difficulty, unraveling such mechanistic drivers is essential for stemming declines and developing management strategies for these ecosystems. Mangroves provide many highly valued ecosystem services to coastal communities, yet worldwide these forests are rapidly declining. Much of this loss is related to various human activities along coastlines, but natural ecological mechanisms contribute to declines in many areas as well. An extensive die-off of dwarf red mangrove (Rhizophora mangle) was observed in a remote area on the west side of Abaco Island, The Bahamas. Preliminary observations suggest the die-off may be due to a combination of fungal pathogens, grazing, and physical stress. This combination of stressors is strikingly parallel to the drivers of salt marsh decline on the East and Gulf coasts of the U.S. To date, different fungal strains from mangrove leaves have been identified. One fungus is a species of Pestalotiopsis, an Ascomycete fungus, and members of this genus are known plant pathogens. There are also high densities of a nocturnally active herbivorous cricket (Tafilasca eleuthera) in die-off areas. It is unclear whether this species has recently colonized the area, is increasing in density, or both. In addition, high salinities in the sediment porewater in the die-off area suggest another potential stressor for the plants. A series of observations and experimental studies will be used to examine potential mechanistic drivers of the mangrove die-off. First, the extent of the die-off areas will be mapped using aerial surveys conducted with a GPS-integrated drone equipped with a video camera. Progression of the die-off will be examined with historical spectral profiles of mangroves from 1980s-present (on an annual basis) using Landsat satellite data. Second, the incidence of lesions on mangroves across Abaco Island and throughout The Bahamas will be explored using a series of citizen science initiatives. Third, identification of fungi will require DNA sequencing and examination of the morphology of fungal spores/conidia at North Carolina State University. Fourth, maintenance of a grazer exclusion experiment near the die-off location will provide an assessment of the role of herbivory in this system. Finally, simulated grazing scar experiments will be used to assess if grazing can indeed facilitate fungal infections.

基础物种是构成整个生态系统的基础的物种，从而大大改变了发现区域的物理和生物学特征。 红树林是最显眼的基础物种群体之一，提供了许多我们高度重视的生态系统服务，例如生态和经济上重要的物种的栖息地，海岸线稳定化和碳储存。 因此，全球红树林的下降是最令人关注的问题。 例如，已经在巴哈马阿巴科岛西侧的一个偏远地区确定了矮红树林的广泛死亡。由于该网站的遥远性质，死亡不太可能直接是由于人类的活动。尽管该地区在很大程度上是无法访问的，但在生态和经济上都很重要，例如，它是阿巴科的主要造虫地区 - 巴哈马每年价值超过1.5亿美元的行业。因此，巴哈马的利益相关者确定衰落的根本原因并评估其他领域的红树林的潜在威胁是迫切关注的。 为此，将进行一系列活动，包括针对最近确定的真菌病原体的广泛调查，实验室的努力，以隔离和鉴定这种病原体，卫星图像映射活动以及模拟的放牧实验。巴哈马国家信托基金会（BNT）目前正在考虑将死亡发生的区域视为国家公园。该研究的结果将直接传达给BNT，并将用于立即做出管理决策。将设计与两个巴哈马环境非政府组织合作，环境之友和巴哈马礁环境教育基金会（BREEF），一项基于公民科学的真菌病变调查以及关于红树林生态学的教育模块。 来自公民科学和学生调查的数据将集成到巴哈马病变的发生率的地图中。 公民科学的组成部分以及与骨鱼指南的互动，为进一步整合科学和教育提供了机会。 教育模块将在7月的Breef夏季教学培训研讨会上介绍。 这项年度活动通常包括来自10个岛屿的30名老师。调查人员将继续通过Abaco科学家网站（http://appliedecology.calsogoly.cals.ncsu.edu.edu/absci/).provisioning在沿海领域中的生态系统服务来使我们的所有研究结果立即为公众提供，并可以通过基金会介导了诸如Mangroves，Coral Salt Marshsssssssssssssssssssssssssssssssssssssslass的基金会。这些物种中的许多人在世界各地正在大幅下降。这些下降通常是由可能难以识别和阐明的复杂，相互作用的压力驱动的。尽管很困难，但揭开这种机械驱动因素对于这些生态系统的减少和制定管理策略至关重要。红树林为沿海社区提供了许多有价值的生态系统服务，但这些森林在全球范围内迅速下降。这种损失的大部分与沿海地线的各种人类活动有关，但是自然生态机制在许多领域也有所下降。在巴哈马阿巴科岛西侧的一个偏远地区观察到了矮红树林（Rhizophora Mangle）的广泛死亡。初步观察表明，死亡可能是由于真菌病原体，放牧和身体压力的结合。这种压力源的结合与迄今为止美国东部和墨西哥湾沿岸的盐沼降低的驱动因素非常平行，已经确定了红树林叶子的不同真菌菌株。一种真菌是一种木偶植物，子宫菌真菌，该属的成员是已知的植物病原体。死亡地区的夜间活跃的草食板球（Tafilasca Elethera）也很高。 目前尚不清楚该物种最近在该区域定居，密度增加还是两者兼而有之。此外，死亡区域的沉积物孔隙水中的高盐度表明植物的另一种潜在压力源。一系列观察结果和实验研究将用于检查红树林死亡的潜在机械驱动因素。 首先，将使用配备摄像机的GPS集成无人机进行的空中调查绘制死亡区域的范围。 使用Landsat卫星数据，将使用1980年代至今（每年）的红树林的历史频谱谱进行研究。 其次，将使用一系列公民科学计划探索整个阿巴科岛和整个巴哈马的红树林的病变发病率。 第三，对真菌的鉴定将需要北卡罗来纳州立大学真菌孢子/分生孢子的形态进行DNA测序和检查。 第四，在死亡地点附近的放牧排除实验的维护将评估草食性在该系统中的作用。 最后，将使用模拟的放牧疤痕实验来评估放牧是否确实可以促进真菌感染。