NSFDEB-NERC - Testing effects of resources and competitors at multiple spatial and temporal scales in multiple populations

人们普遍认识到，猎物数量不仅受到直接捕食的限制，而且受到避免捕食的成本（“风险效应”）的限制。从逻辑上讲，风险效应可能也存在于竞争性互动中。我们建议测试风险规避是否会带来能量成本，从而转化为对非洲野狗这一次要竞争对手的生存、繁殖、种群动态和基因流动的影响。为了做到这一点，我们将把新的方法纳入我们正在进行的非洲野狗、狮子和猎物种群在三个生态系统中的长期研究中。具体来说，我们将把对野狗的直接观察与配备GPS项圈、高频三轴加速度计和磁场强度传感器的动物的数据结合起来，这将为我们提供非常精细的数据，包括运动、动态身体加速度、能量消耗和能量获得，以便野狗在已知狮子和猎物密度和分布的地区狩猎。三轴加速度计将提供矢量动态身体加速度（VeDBA）的详细和精确测量，这是一种能量消耗的强大代理，时间尺度从秒到天或月不等。GPS项圈将根据运动模型（特别是动态布朗桥模型- dbbmm）提供从小时到年的时间尺度上的空间使用和运动推断。这些运动模型的模型，适合由VeDBA、磁场强度和GPS位置组合得出的轨迹，使用一种称为“航位推算”的过程（其中动物的运动模式是通过使用运动数据的向量得出的），将测试对运动的影响，精确到秒的尺度。在连续三天的“跟踪”中对同一个体进行直接观察，将提供与猎物相遇、狩猎和杀戮的时空匹配数据，以小时到年的时间尺度量化能量获得，并将为解释其他数据提供关键背景。通过将这些数据与对已知个体的密集、长期监测相结合，我们将测试与生存、繁殖和种群动态（使用贝叶斯综合种群模型）的关系，以及使用我们开发和验证的SNP芯片对基因流的影响。通过在三个生态系统中对竞争对手和猎物密度的变化进行精确测量，我们将获得一系列生态条件的数据，这些数据在单一地点是不可能获得的。

It is widely recognized that prey populations can be limited not only by direct predation, but also by the costs of avoiding predation ('risk effects'). Logic suggests that risk effects might also exist in competitive interactions. We propose to test whether the avoidance of risk carries energetic costs that translate into effects on survival, reproduction, population dynamics and gene flow in a subordinate competitor, the African wild dog. We will do this by incorporating new methods into our ongoing long-term studies of African wild dog, lion and prey populations in three ecosystems. Specifically, we will couple direct observation of wild dogs to data from animals equipped with GPS collars, high frequency triaxial accelerometers and magnetic field intensity sensors, which, together, will give us very fine-scaled data on movement, dynamic body acceleration, energy expenditure and energy gain for wild dogs hunting in areas with known densities and distributions of lions and prey. Triaxial accelerometers will provide detailed and precise measurements of vectorial dynamic body acceleration (VeDBA), a powerful proxy for energy expenditure at time scales ranging from seconds to days or months. GPS collars will provide inferences on space use and movement from movement models (particularly dynamic Brownian bridge models - dBBMMs) at time scales from hours to years. These models of movement models, fit to trajectories derived from a combination of VeDBA, magnetic field intensity and GPS locations using a process termed 'dead-reckoning' (where animal movement patterns are derived from using vectors on movement data), will test for effects on movement down to the scale of seconds. Direct observation of the same individuals in continuous three-day 'follows' will provide spatiotemporally matched data on encounters with prey, hunts and kills to quantify energy gain at time scales from hours to years, and will provide critical context for the interpretation of other data. By pairing these data with intensive, long-term monitoring of known individuals, we will test relationships with survival, reproduction and population dynamics (using a Bayesian integrated population model), and effects on gene flow using a SNP chip we have developed and validated. With replication across three ecosystems with well-measured variation in the densities of competitors and prey, we will obtain data for a range of ecological conditions that would not be possible with a single site.