Movement and spatial consumer-resource dynamics in a rapidly changing world

在过去的20年里，我们在理解影响动物运动过程的多种因素方面取得了巨大的进步。对气候变化和人为景观干扰对空间动态和种群生存能力的影响的关注较少。我的长期目标是确定食草动物迁徙的因果机制联系，确定运动如何导致消费者及其资源丰度的局部协变，模拟空间过程对消费者-资源动态的影响，并使用这些模拟模型来评估气候变化和人为干扰对迁徙食草动物生存能力的影响。我建议使用理论和现场技术相结合的方法，在三个有迁徙草食动物种群的生态系统中解决这些目标：(1)塞伦盖蒂国家公园开阔平原和树木繁茂草原中的角马和汤姆森瞪羚，(2)斯堪的纳维亚山区的野生和驯化驯鹿，以及(3)安大略省北部北方森林中的迁徙林地驯鹿。实地研究将仅限于非洲和斯堪的纳维亚地区，因为已经获得了林地驯鹿的相关实地测量数据。理论模型将被完全整合到所有三个生态系统中，并使用空间显式模拟模型来探索运动和空间动力学对生态相互作用的影响。 捕食风险将通过绘制捕食者在整个地形上的利用分布图来评估，并以草食动物丰度的局部变化为权重，因为在大多数捕食者功能反应中，风险通常与局部猎物丰度成反比。能量效益将通过直接观察或通过安装在无线电项圈上的动物携带的摄像机估计草食动物的饮食，结合来自现场分析的可消化能量的标准实验室分析来评估。能源成本将通过加速计进行评估，加速计通常安装在GPS无线电项圈中，根据行为观察进行校准。空间显式的基于智能体的模拟将用于评估观察到的运动轨迹的影响，方法是综合整个年度迁徙周期的风险、能量收益和能量成本。观察到的所有4个物种的运动轨迹将使用多阶段状态空间模型来估计转折率、方向偏差和步长的组合，条件是当地的景观特征、季节性和动机状态。由此产生的运动模型将被合并到空间显式的基于主体的模拟模型中，以评估与现实的环境随机性水平相关的种群生产力和长期生存能力的长期趋势。

The past 2 decades has witnessed enormous advances in our understanding of the multitude of factors influencing animal movement processes. Less attention has been devoted to the impact of climate change and anthropogenic landscape disturbance on spatial dynamics and population viability. My long-term objectives are to identify causal mechanistic links for herbivore migration, determine how movement contributes to local co-variation in the abundance of consumers and their resources, model the impact of spatial processes on consumer-resource dynamics, and use those simulation models to evaluate the impact of climate change and anthropogenic disturbance on the viability of migratory herbivores. I propose to address these objective using a mix of theoretical and field techniques in three well-studied ecosystems populated by migratory herbivore populations: (1) wildebeest and Thomson's gazelles in the open plains and wooded grasslands of Serengeti National Park, (2) wild and domesticated reindeer in the montane regions of Scandinavia, and (3) migratory woodland caribou in the boreal forests of northern Ontario. Field studies will be restricted to just the African and Scandinavian sites, since the relevant field measurements have already been obtained for woodland caribou. Theoretical modeling will be fully integrated into all 3 ecosystems, with spatially-explicit simulation models used to explore the implications of movement and spatial dynamics for ecological interactions. Predation risk will be assessed by mapping the utilization distribution of predators across the landscape, weighted by local variation in herbivore abundance since risk is generally inversely related to local prey abundance in most predator functional responses. Energetic benefits will be assessed by estimating herbivore diet either by direct observation or from animal-borne video cameras attached to radio-collars, combined with standard lab assays of digestible energy from proximate analysis. Energetic costs will be assessed by accelerometers routinely incorporated into GPS radio-collars, calibrated against behavioral observations. Spatially-explicit agent-based simulations will be used to evaluate the impact of observed movement trajectories, by integrating risk, energetic gain, and energetic costs over the entire annual migratory cycle. The observed movement trajectories for all 4 species will be modeled using multiphasic state-space models to estimate combinations of turn rates, directional bias, and step lengths conditioned on local landscape features, seasonality, and motivational state. The resulting movement models will be incorporated into spatially-explicit agent-based simulation models to evaluate long-term trends for population productivity and long-term- viability in relation to realistic levels of environmental stochasticity.