Spatio-Temporal Mosaics in Cycling Populations: The Role of Species Interactions

种群动态中时空变异性的明显增加引起了相当大的兴趣，包括种群大小、周期倾向和一些自由活动的昆虫、鸟类和哺乳动物的地理分布的变化。气候变化和其他大范围的压力因素被指责为这种现象的罪魁祸首，但迄今为止，物种相互作用的机制框架尚未得到仔细审查。该研究计划将解决与物种相互作用在周期性衰减和地理范围损失中的作用有关的悬而未决的问题。首先，在加拿大山猫的南部种群中，我们将通过对捕食者协会(山猫、郊狼、山猫)的GPS遥测监测空间位移，来评估竞争(即冲突)对山猫行为的影响。剥削性竞争(即食物)假说将通过对三种食肉动物范围内的稳定同位素分析来检验，并根据猎物的可获得性和食肉动物的共生水平来检查食物重叠的程度。其次，雪鞋兔对感知到的捕食风险的反应将通过实地实验来检验，该实验改变了雪鞋兔分布的核心和外围的这种风险，并记录了行为、生理和人口统计的反应。捕食对野兔种群周期的直接和间接作用，包括通过与气候的相互作用，将通过种群模型进行评估。第三，我们将比较当前的种群分析方法，以确定哪种方法对检测生态数据集中的周期性和周期性衰减最敏感，然后使用全球人口动力学数据库检查这些动态属性的流行度。第四，我们将通过使用轮虫-藻类(捕食者-猎物)系统进行实验，明确测试竞争和捕食风险对循环动力学的作用，该系统允许我们推断种群水平的反应。因此，这个项目将提供全面的洞察物种相互作用对种群变化模式的作用，从而帮助我们更好地理解为什么许多自然种群似乎正在经历动态变化。

There is considerable interest in the apparent increase in spatio-temporal variability in population dynamics, including changes in population size, cyclic propensity, and geographic distribution of a number of free-ranging insects, birds, and mammals. Climate change and other broad-scale stressors have been blamed for such phenomena, but to date a mechanistic framework for the role of species interactions has not been given careful scrutiny. The research program will resolve outstanding questions related to the role of species interactions in cyclic attenuation and geographic range loss. First, in a southern population of Canada lynx, we will evaluate the role of agonistic competition (i.e. strife) on lynx behaviour via monitoring spatial displacement via GPS telemetry of the predator guild (lynx, coyote, bobcat). The exploitative competition (i.e., food) hypothesis will be examined by conducting stable isotope analysis for the 3 carnivores across their range, and examining the extent of dietary overlap according to prey availability and carnivore levels of sympatry. Second, snowshoe hare responses to perceived predation risk will be examined via a field experiment altering such risk in the core and periphery of their distribution and documenting behavioural, physiological, and demographic responses. The direct and indirect role of predation on hare population cycles, including through interaction with climate, will be assessed via population models. Third, we will compare contemporary methods of population analysis to determine which is most sensitive to detecting cyclicity and cyclic attenuation in ecological datasets, and then examine the prevalence of these dynamical properties using the Global Population Dynamics Database. Fourth, we will explicitly test the role of competition and predation risk on cyclic dynamics by conducting experiments using a rotifer-alga (predator-prey) system that allows us to infer population-level responses. Thus, collectively this program will provide comprehensive insight into the role of species interactions on patterns of population change, and thereby help us better understand why many natural populations seem to be undergoing dynamical variability.