Population dynamics and conservation of animals in seasonal environments

从北极到热带生态系统，几乎所有的生物都经历着某种形式的季节性，其特征是在一个年度周期中的资源波动。每年的资源波动通常会导致相对较长的时期，在此期间动物只致力于获取生存资源（即非繁殖期），其间穿插着较短的时期，重点转移到繁殖（即繁殖期）。繁殖季节和非繁殖季节之间的这种交替可能对个体适应度和种群动态产生重要影响，但这对我们分解种群增长驱动因素和确定哪个季节导致种群下降的能力构成了重大障碍。这主要是因为绝大多数野生动物的研究仍然集中在一年周期的单一时期（通常是繁殖）。在接下来的5年里，我建议采取多层次的方法来实现我的长期目标，即了解居民和移民人口如何应对环境变化。我的前两个目标侧重于使用长期数据集（30年以上）来了解整个年度周期中的事件如何影响人口增长率的年度变化。目的（1）关注一种数量下降的北方留鸟--灰冠松鸦（Perisoreus canadensis）的携带效应和气候变化。目的（2）着重于多个季节中密度和气候的变化如何限制和调节一种候鸟，萨凡纳麻雀（Passerculus sparichensis）。我的第三个目标（3）是使用我们现在已经建立的实验室系统（黑腹果蝇的季节性种群），结合野生种群的数据，来检查物种种群计数中是否存在季节特异性信号，这些信号可以表明种群下降是繁殖地还是非繁殖地发生的结果。我提出的工作将新兴概念（季节性相互作用，完整的年周期模型）与创新的数学模型（IPM & SEM）和最先进的现场跟踪方法（ICARUS，Motus）相结合，并明确旨在测试环境变化引起的人口下降的因果机制。通过将我们新颖的实验室系统与我们的野生系统和公民科学数据的预测模型相结合，我们还探索了一种新的研究途径，为确定保护资源应该最有效地分配到哪里提供了希望。我的研究不仅将导致对我们的焦点生物有价值的见解，而且还提供了基本的例子，说明如何将季节性纳入理解驱动人口增长的机制至关重要。

From Arctic to tropical ecosystems, virtually all organisms experience some form of seasonality' that is characterized by resource fluctuations over the course of an annual cycle. Annual resource fluctuations typically result in relatively long periods in which animals are devoted only to acquiring resources to survive (i.e. the non-breeding period) interspersed with a shorter period(s) where to focus shifts to reproduction (i.e. the breeding period). This alternation between breeding and nonbreeding seasons can have important consequences for individual fitness and population dynamics but has posed a major barrier in our ability to decompose the drivers of population growth and identify which season is driving declines. The primary reason for this is because the vast majority of studies in the wild still focus on a single period of the annual cycle (usually breeding).*** Over the next 5 years, I propose to take a multi-tiered approach to address my long-term goal of understanding how resident and migratory populations respond to environmental change. My first two objectives focus on using long-term datasets (30+ yrs) to understand how events throughout the annual cycle contribute to annual variation in population growth rates. Objective (1) focuses on carry-over effects and climate change in a declining boreal resident bird, the gray jay (Perisoreus canadensis). Objective (2) focuses on how variation in density and climate in multiple seasons act to limit and regulate a migratory bird, the Savannah sparrow (Passerculus sandwichensis). My third objective (3) is to use our now well-established experimental lab system (seasonal populations of Drosophila melanogaster), in conjunction with data from wild populations, to examine whether there are season-specific signals in species population counts that can indicate if population declines are a result of what is occuring on the breeding or non-breeding grounds.*** My proposed work combines emerging concepts (seasonal interactions, full annual cycle models) with innovative mathematical models (IPM & SEM) and state-of-the-art field tracking methods (ICARUS, Motus) and is explicitly designed to test causal mechanisms underlying population declines caused by environmental change. By combining our novel laboratory system with predictive models from our wild systems and citizen science data, we also explore a new avenue of research that offers promise for identifying where conservation resources should be most effectively allocated. My research will not only lead to valuable insights into our focal organisms but also provide fundamental examples of how incorporating seasonality is critical for understanding the mechanisms driving population growth.**