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，但由于人类活动的威胁，珊瑚礁正在迅速退化。沉积物径流与珊瑚衰退和藻类占主导地位有关，但我们对沉积物对珊瑚礁生物的影响了解有限，包括对防止藻类不受控制生长的食草鱼类的影响。研究人员正在研究沉积对几种食草性珊瑚鱼的影响，包括它们是否留在或撤离受影响的珊瑚礁。他们还描述了沉积作用、食草率和珊瑚覆盖之间的关系。通过确定可能保护食草动物生物量和藻类去除率的关键沉积物阈值，结果为珊瑚礁管理工作提供了信息。该项目将为本科生、研究生和博士后科学家提供研究培训。研究人员正在通过与夏威夷科学探究教育计划（SIEP）的新伙伴关系向当地社区推广珊瑚礁教育，这是一个“提前录取”的大学课程，其中包括高中生的文化框架研究经验。最后，该项目的成果正在通过“海洋之声”的一个电视节目广泛分享，这是一个连接研究和文化的成熟电视和在线流媒体系列节目。草食性鱼类是至关重要的，在防止和/或扭转相移，但最近的研究结果显示，极端敏感的草食性珊瑚礁鱼类沉积物暴露，这反过来又可能导致迅速下降的丰度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。研究人员将野外生态学、动物行为学和数学模型相结合，以解决三个主要目标：1）评估草食性鱼类对野外沉积物梯度的时空功能反应; 2）验证草食性鱼类对体内沉积物暴露的行为反应;和3）建立一个机制框架，预测沉积物径流对脆弱珊瑚礁提供草食性鱼类功能和珊瑚藻类动态的影响。总的来说，这项研究提供了一个综合的观点，什么特点沉积物暴露限制和什么出错时，超过限制，同时澄清沉积，草食动物和生态相变的风险之间的机械联系。成果是建立沉积物的亚致死限度，为保护和管理工作提供信息，并与夏威夷的利益攸关方分享。该项目由NSF海洋科学部的生物海洋学计划和刺激竞争性研究的既定计划（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知识价值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.