Predicting spatial and temporal responses of herbivorous coral reef fishes to sediment runoff

热带珊瑚礁是世界上生物多样性最丰富的生态系统之一，但由于人为威胁，它们正在迅速退化。沉积物径流与珊瑚衰退和藻类优势有关，但我们对沉积物对珊瑚礁生物的影响了解有限，包括对防止藻类失控生长的草食性鱼类的影响。研究人员正在研究沉积对几种食草性珊瑚礁鱼类的影响，包括它们是留在受影响的珊瑚礁中还是撤离。他们还描述了沉积作用、食草率和珊瑚覆盖率之间的关系。结果通过确定可能保护草食动物生物量和藻类去除率的关键沉积物阈值，为珊瑚礁管理工作提供信息。该项目将为本科生、研究生和博士后科学家提供研究培训。调查人员正在通过与夏威夷科学探究教育项目(SIEP)的新合作，向当地社区推广珊瑚礁教育。SIEP是一门提前录取的大学课程，其中包括为高中生提供的文化框架研究体验。最后，这个项目的成果通过电视节目《海洋之声》被广泛分享，这是一部连接研究和文化的成熟的电视和在线流媒体系列剧。沉积物径流与珊瑚退化和以珊瑚为主向以藻类为主的转变有关。草食性鱼类在防止和/或逆转相变方面至关重要，但最近的研究结果表明，草食性珊瑚礁鱼类对沉积物暴露极其敏感，这反过来可能导致丰度迅速下降和自上而下的藻类控制。该项目的主要目标是揭示沉积物暴露如何以及在多大程度上侵蚀珊瑚礁生态系统中的鱼类功能。研究人员正在结合野外生态学、动物行为和数学模型来解决三个主要目标：1)评估草食性鱼类对野外沉积物梯度的时空功能反应；2)验证草食性鱼类对活体沉积物暴露的行为反应；3)建立一个机制框架，预测沉积物径流对草食性鱼类功能和脆弱珊瑚礁上珊瑚-藻类动态的影响。总体而言，这项研究提供了一个综合的观点，说明了沉积物暴露限制的特点以及超过限制时会出现什么问题，同时澄清了沉积、草食和生态相变风险之间的机械联系。研究成果正在建立沉积物的亚致死极限，以指导保护和管理工作，并正在与夏威夷的利益相关者分享。该项目由NSF海洋科学部门的生物海洋学项目和既定的激励竞争研究计划(EPSCoR)共同资助。该奖项反映了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。

Tropical coral reefs are one of the world’s most biodiverse ecosystems but are rapidly degrading due to anthropogenic threats. Sediment runoff is associated with coral decline and algal dominance, yet we have a limited understanding of the impacts of sediment on reef organisms, including on herbivorous fishes that prevent uncontrolled algae growth. The investigators are examining the effects of sedimentation on several species of herbivorous reef fish, including whether they remain in or evacuate affected reefs. They are also characterizing the relationship between sedimentation, herbivory rates, and coral cover. Outcomes are informing reef management efforts by identifying critical sediment thresholds that may preserve herbivore biomass and algal removal rates. This project will provide research training for undergraduates, graduate students, and a postdoctoral scientist. The investigators are promoting coral reef education to local communities through a new partnership with the Hawai’i Science Inquiry Education Program (SIEP), an “early admit” college course that includes a culturally framed research experience for high school students. Finally, results of this project are being shared widely via a TV episode on Voice of the Sea, an established TV and online streaming series that connects research and culture.Sediment runoff is associated with coral degradation and shifts from coral- to algal-dominance. Herbivorous fishes are critical in preventing and/or reversing phase shifts, yet recent findings reveal extreme sensitivity of herbivorous reef fishes to sediment exposure, which in turn may lead to rapid decline in abundance and top-down algal control. The main goal of this project is to reveal how and to what extent sediment exposure erodes fish function in coral reef ecosystems. The investigators are combining field ecology, animal behavior, and mathematical modeling to address three main objectives: 1) Assessment of spatio-temporal functional responses of herbivorous fishes to sediment gradients in the wild; 2) Validation of behavioral responses of herbivorous fishes to sediment exposure in-vivo; and 3) Construction of a mechanistic framework for predicting consequences of sediment runoff for the delivery of herbivorous fish functions and coral-algal dynamics on vulnerable reefs. Overall, this study offers an integrated view of what characterizes sediment exposure limits and what goes wrong when limits are surpassed, while clarifying the mechanistic links between sedimentation, herbivory, and the risk of ecological phase shifts. Outcomes are establishing sublethal limits to sedimentation to inform conservation and management efforts and are being shared with stakeholders in Hawai’i. This project is jointly funded by the Biological Oceanography Program in NSF's Division of Ocean Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).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.