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会发生独特而鲜为人知的相互作用，其中一个捕食者会影响猎物，使他们更容易受到其他类型的捕食者的影响。在大型捕食性中上层物种(海豚、金枪鱼、旗鱼、鲨鱼)之间的这种“促进”相互作用期间，大型捕食性中上层物种(海豚、金枪鱼、旗鱼、鲨鱼)从下面攻击饲料鱼，将密集的鱼群驱赶到水面，在那里它们成为空中捕食者(海鸟)的食物。这些相互作用很难观察到，这是有问题的，因为它们可能对许多据信依赖于便利觅食的海鸟物种特别重要。在这个项目中，我们将开发一种方法来远程观察这些相互作用，使用一种新的生物记录设备(GPS、相机、加速计、心率记录仪和胃温记录仪)的组合，并结合用于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描述这些相互作用，并衡量便利化在多大程度上提高了热带远洋海鸟的觅食效率。该项目将在帕尔米拉环礁与NOAA、美国鱼类和野生动物管理局以及自然保护协会合作，努力就促进捕食者的重要性及其对世界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的性质和重要性，这是两种捕食者之间以共同猎物为目标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，该项目将开发方法，通过使用新的统计建模技术在分析中结合一套独特的生物记录设备的数据，远程检测促进相互作用并评估其对觅食海鸟的能量影响。具体地说，动物携带的相机将与部署在红脚乳鸽(Sula Sula)上的GPS遥测相结合，以表征中太平洋巴尔米拉环礁周围便利的觅食互动。摄像机将直接观察促进作用的存在，并潜在地观察其他捕食者的分类组成，而鸟载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观察到的运动模式检测促进作用。最后，为了证明可行性，这些模型将适用于GPS跟踪的个体，同时携带测量能量消耗(三轴加速计、心率记录器)和增益(胃温记录器)的生物记录设备，以评估便利对觅食海鸟整体能量平衡的相关能量影响。这些观察将辅之以更传统的方法，以证明这种方法在技术上的可行性，以衡量便利觅食对在公海觅食的自由生活个体的影响。一旦开发出来，就有可能将这种生态相互作用的重要性与海鸟在种群水平上的繁殖成功联系起来，这样就可以通过现有的生物记录技术和统计建模方法对觅食行为进行精确观察。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。

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.