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

种群动态的时空变异性明显增加，包括种群规模、循环倾向和一些自由放养的昆虫、鸟类和哺乳动物的地理分布的变化，引起了相当大的兴趣。气候变化和其他大范围的压力源被认为是造成这种现象的原因，但迄今为止，物种相互作用的机制框架还没有得到仔细的审查。该研究计划将解决与物种相互作用在循环衰减和地理范围丧失中的作用有关的悬而未决的问题。首先，在加拿大南部的一个猞猁种群中，我们将通过GPS遥测监测捕食者群体（猞猁、土狼、山猫）的空间位移，来评估激烈竞争（即冲突）对猞猁行为的作用。利用性竞争（即食物）假说将通过对三种食肉动物在其活动范围内进行稳定同位素分析来检验，并根据猎物可获得性和食肉动物的同栖水平来检验饮食重叠的程度。其次，将通过实地实验来检查雪鞋兔对感知捕食风险的反应，改变其分布的核心和外围的这种风险，并记录行为、生理和人口反应。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，我们将比较当代的种群分析方法，以确定哪种方法对检测生态数据集中的周期性和循环衰减最敏感，然后使用全球种群动态数据库检查这些动态特性的普遍性。第四，我们将明确测试竞争和捕食风险在循环动力学中的作用，通过使用轮虫-藻类（捕食者-猎物）系统进行实验，使我们能够推断种群水平的反应。因此，总的来说，这个项目将为物种相互作用在种群变化模式中的作用提供全面的见解，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.