Collaborative Research: Predator facilitation across a variable marine environment.

在开阔的海洋中，顶端捕食者之间可能发生独特而鲜为人知的相互作用，其中一个捕食者影响猎物，使它们更容易受到其他类型捕食者的影响。在这种大型食肉远洋物种（海豚、金枪鱼、旗鱼、鲨鱼）之间的“促进”相互作用中，它们从下面攻击饲料鱼，将密集的鱼群驱赶到水面，在那里它们可以被空中捕食者（海鸟）利用。这些相互作用很难观察到，这是一个问题，因为它们可能对许多被认为依赖于便利觅食的海鸟物种特别重要。在这个项目中，我们将开发远程观察这些相互作用的方法，使用生物记录设备（GPS、相机、加速度计、心率记录仪和胃温记录仪）的新组合，以及分析动物跟踪数据的新统计方法。这将使研究人员能够更准确地检测和表征这些相互作用，并测量促进作用提高热带远洋海鸟觅食效率的程度。该项目将与美国国家海洋和大气管理局、美国鱼类和野生动物管理局以及大自然保护协会合作，在巴尔米拉环礁开展，旨在就促进捕食者的重要性及其对全球海鸟种群的潜在损失提供管理指导。四所参与大学的研究生和本科生将参与研究，并获得宝贵的实践教育和培训经验。该项目将调查公海捕食者促进作用的性质和重要性，这是两个捕食者针对共同猎物的关键但被忽视的特征介导的相互作用。为了实现这些目标，该项目将开发远程检测促进相互作用的方法，并通过使用新颖的统计建模技术结合一套独特的生物设备进行分析，评估它们对觅食海鸟的能量影响。具体来说，动物携带的相机将与部署在红脚鲣鸟（Sula Sula）身上的GPS遥测技术相结合，以表征太平洋中部巴尔米拉环礁周围便利的觅食互动。相机将直接观察到便利的存在和其他捕食者的潜在分类组成，而鸟类携带的GPS数据将记录这些相互作用的运动模式、位置和频率。有了这些数据，研究人员将开发贝叶斯动态参数运动模型，在没有收集相机数据的情况下，仅从gps观察到的运动模式中检测便利化。最后，在示范可行性的试点基础上，这些模型将适用于携带生物记录设备(测量能量消耗（三轴加速度计，心率记录器）和增加（胃温记录器）的GPS跟踪个体，以评估促进对觅食海鸟整体能量平衡的相关能量影响。这些观察结果将以更传统的方法加以补充，以证明这种方法在技术上的可行性，以衡量在开阔海洋中觅食的自由生活个体的便利觅食的影响。一旦开发出来，就有可能将这种生态相互作用的重要性与可以类似观察到的海鸟种群水平上的繁殖成功联系起来，从而通过现有的生物学技术和统计建模方法对觅食行为进行精确观察。该奖项反映了美国国家科学基金会的法定使命，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。

In the open ocean, unique and poorly understood interactions between apex predators can take place, where one predator influences prey to make them more susceptible to other types of predators. During such “facilitation” interactions between large, predatory pelagic species (dolphins, tunas, swordfish, sharks) attack forage fish from below, driving dense aggregations to the surface where they become available to aerial predators (seabirds). These interactions are hard to observe, which is problematic because they may be particularly important for numerous seabird species believed to be dependent on facilitated foraging. During this project, we will develop methods to remotely observe these interactions using a novel combination of biologging devices (GPS, cameras, accelerometers, heart rate loggers, and stomach temperature loggers) in concert with new statistical approaches for analyzing animal tracking data. This will allow the investigators to detect and characterize these interactions more accurately and measure the degree to which facilitation improves foraging efficiency in tropical pelagic seabirds. The project will occur at Palmyra Atoll in partnership with NOAA, the US Fish and Wildlife Service, and The Nature Conservancy in an effort to provide management guidance regarding the importance of predator facilitation and its potential loss on seabird populations world-wide. Graduate and undergraduate students at the four participating universities will be involved in research and receive valuable hands-on educational and training experiences.This project will investigate the nature of and importance of open-ocean predator facilitation, a key but overlooked trait-mediated interaction between two predators that target a common prey. To achieve these objectives, the project will develop methods to remotely detect facilitation interactions and evaluate their energetic consequences to foraging seabirds by combining data from a unique suite of biologging devices in analyses using novel statistical modeling techniques. Specifically, animal-borne cameras will be combined with GPS telemetry deployed on red-footed boobies (Sula sula) to characterize facilitated foraging interactions around Palmyra Atoll in the central Pacific. Cameras will directly observe the presence of facilitation and potentially the taxonomic composition of other predators, while bird-borne GPS data will record movement patterns, location, and frequency of these interactions. With these data, the investigators will develop Bayesian dynamic parameter movement models that detect facilitation from GPS-observed movement patterns alone, when camera data are not collected. Finally, on a pilot basis to demonstrate feasibility, the models will then be fit to individuals tracked by GPS while carrying biologging equipment that measures energetic expenditure (triaxial accelerometry, heart rate loggers) and gain (stomach temperature loggers) to evaluate the associated energetic impact of facilitation on overall energy balance of foraging seabirds. These observations will be supplemented with more traditional approaches to demonstrate the technical feasibility of this approach for measuring the impacts of facilitated foraging in free living individuals that forage in the open ocean. Once developed, it will be possible to relate the importance of this ecological interaction to breeding success at the population-level for seabirds that can be similarly observed, making precise observation of foraging behaviors possible from available biologging technologies and statistical modeling approaches.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.