Spatial ecology and predator-prey dynamics

大量的理论表明，大多数捕食者-猎物系统应该倾向于丰富的极端循环，然而这样的循环在自然界是罕见的。对这一悖论的一个合理解释是，捕食者和猎物的微弱混合导致了当地种群动态的非同步变化。我的长期目标是确定运动过程、空间分布模式和捕食者-猎物动态之间的因果机制联系。空间显式模型和实验试验将用于评估弱混合对稳定捕食者-猎物动力学的作用程度。我建议采用理论、实地和实验室方法相结合的方法来实现这一目标。拟议的野外工作扩展了我们正在进行的对塞伦盖蒂国家公园一组大型食草动物和食肉动物的行为和动力学的观察研究。它是基于复杂随机行走过程的计算机模型、遥感景观特征、卫星GPS无线电项圈、加速度计和安装在动物身上的摄像机项圈的最先进的组合，即使动物在视线之外也能观察它们的行为。拟议的实验室工作回应了一个令人兴奋的新机会，即使用圭尔夫大学的一个名为Limnotron的独一无二的设备，在控制条件下，实验测试运动过程如何促进空间动力学和大量水生中生态系统中食物网的相互作用。在这两种情况下，我们都研究了资源的流动群体及其消费者，他们的行为、摄食、运动和人口参数可以从个体的观察中估计出来，然后这些参数与空间分布模式和在更粗的时空尺度上测量的种群动态有关。理论建模很好地整合到现场和实验室计划中，以充分探索生态相互作用的运动和空间动力学的含义。这些模型将帮助我们建立空间过程与其生态后果之间的概念联系。这是朝着确定在景观尺度上保护和管理复杂自然生态系统的最佳方法迈出的重要一步。

A large body of theory suggests that most predator-prey systems should be prone to extreme cycles in abundance, yet such cycles are rare in nature. One plausible explanation for this paradox is that weak mixing of predators and prey produces asynchronous variation in local population dynamics. My long-term objective is to identify causal mechanistic links between movement processes, patterns of spatial distribution, and predator-prey dynamics. Spatially-explicit models and experimental trials will be used to evaluate the degree to which weak mixing serves to stabilize predator-prey dynamics. I propose to address this objective using a combination of theoretical, field and laboratory approaches. The proposed field work extends our ongoing observational studies of behavior and dynamics of a suite of large herbivores and carnivores in Serengeti National Park. It is based on a state-of-the-art combination of computer models of complex random walk processes, remotely-sensed landscape features, satellite GPS radio-collars, accelerometers, and animal-mounted video camera-collars to observe behavior even when animals are out of sight. The proposed laboratory work responds to an exciting new opportunity to use a one-of-a-kind facility at the University of Guelph, called the Limnotron, to test experimentally how movement processes contribute to spatial dynamics and food-web interactions under controlled conditions in massive aquatic mesocosms. In both cases, we study mobile populations of resources and their consumers whose behavior, feeding, movement, and demographic parameters can be estimated from observations of individuals, which are then related to spatial distribution patterns and population dynamics measured at coarser temporal and spatial scales. Theoretical modeling is well-integrated into both the field and laboratory programs, to fully explore the implications of movement and spatial dynamics for ecological interactions. These models will help us to forge conceptual links between spatial processes and their ecological consequences. This is an important step towards identifying the best means of conserving and managing complex natural ecosystems at a landscape scale.