The Geographic Mosaic of Coevolution for Bird-dispersed Pines, Clark's Nutcrackers and Pine Squirrels

生物学的一个基本挑战是了解各种生物过程是如何组织整个景观中的生物多样性的。通过实地研究和鸟类实验，研究人员建议研究群落环境(即潜在相互作用的物种群体，特别是松鼠的存在和不存在)如何影响北美西部山区种子传播者(克拉克胡桃夹子；一种鸣禽)和两种松树(软皮松和白皮松)之间互利互动的结果。对群落背景的理解尤其重要，因为生境碎片化、物种引进和其他人为干扰可能会重新安排群落，从而改变物种之间的相互作用。调查人员将回答两个基本问题。首先，他们将确定一种拮抗剂(松鼠)的存在和不存在如何影响相互作用，以及这反过来可能如何影响松林的发展。其次，他们将检验这样一个假设，即鸟类在松树上的扩散只有在没有松鼠的情况下才会进化。这项研究的更广泛的影响包括进一步了解多样性的地理模式是如何产生的，这对长期的保护工作至关重要。此外，软皮松和白皮松都在经历戏剧性的衰退，这主要是由于一种导致白松水泡锈病的入侵病原体。这项研究将进一步加深我们对控制种子传播和林分更新的因素的理解，这两个因素在这个系统中是至关重要的，因为如果依靠自然更新，长期的保护努力可能会更成功。更好地了解松树的补充很重要，因为这两种松树和胡桃夹子的存在决定了北美西部整个亚高山生态系统的生长和建立。最后，至少有一名博士生将接受培训。

A fundamental challenge of biology is to understand how various biological processes organize biodiversity across the landscape. By using both field studies and aviary experiments, the investigators propose to examine how community context (i.e., the groups of potentially interacting species and in particular the presence and absence of pine squirrels) affect the outcome of a mutualistic interaction between a seed disperser (Clark's Nutcracker; a species of songbird) and two species of pines (limber and whitebark pine) in the mountains of western North America. An understanding of community context is especially relevant because habitat fragmentation, species introductions and other anthropogenic disturbances may rearrange communities and thus the interactions among species. The investigators will answer two fundamental questions. First, they will determine how the presence and absence of an antagonist (pine squirrels) influences a mutualistic interaction and how this in turn may affect the development of pine forests. Second, they will test the hypothesis that bird dispersal in pines only evolves in the absence of pine squirrels. Broader impacts of this research include furthering our understanding of how geographic patterns of diversity arise, which is critical for long-term conservation efforts. Moreover, both limber and whitebark pines are undergoing dramatic declines due largely to an invasive pathogen that causes white pine blister rust. This research will further our understanding of the factors that govern seed dispersal and stand regeneration, which are critical in this system because long-term conservation efforts will likely be more successful if they rely on natural regeneration. A better understanding of pine recruitment is important because the presence of these two species of pines and nutcrackers determines the growth and establishment of an entire subalpine ecosystem in western North America. Finally, at least one Ph.D. student will be trained.