Spatial ecology and predator-prey dynamics

一大堆理论表明，大多数捕食者-猎物系统应该容易出现大量的极端循环，但这样的循环在自然界中很少见。对这一悖论的一个看似合理的解释是，捕食者和猎物的弱混合导致了当地种群动态的异步变化。我的长期目标是确定运动过程、空间分布模式和捕食者-猎物动力学之间的因果机制联系。空间显式模型和实验试验将被用来评估弱混合在多大程度上有助于稳定捕食者-猎物动力学。我建议采用理论、实地和实验室相结合的方法来解决这一目标。拟议的实地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。它基于最先进的计算机模型的组合，包括复杂的随机行走过程、遥感景观特征、卫星GPS无线电项圈、加速计和动物安装的视频摄像机项圈，即使在动物看不到的情况下也能观察动物的行为。拟议的实验室工作是对一个令人兴奋的新机会的回应，该机会利用圭尔夫大学一种名为Limnotron的独一无二的设施，通过实验测试在大型水生中观系统中，运动过程如何在受控条件下对空间动力学和食物网相互作用做出贡献。在这两种情况下，我们研究了资源及其消费者的流动人口，他们的行为、进食、移动和人口参数可以通过对个人的观察来估计，然后这些参数与在更粗的时间和空间尺度上测量的空间分布模式和人口动态有关。理论建模被很好地整合到现场和实验室项目中，以充分探索运动和空间动力学对生态相互作用的影响。这些模型将帮助我们在空间过程及其生态后果之间建立概念上的联系。这是确定在景观范围内保护和管理复杂自然生态系统的最佳手段的重要一步。

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.