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不同的生物过程如何组织整个景观的生物多样性。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（软木松和白皮松）之间互惠相互作用的结果。对群落背景的了解尤其重要，因为栖息地破碎化、物种引入和其他人为干扰可能会重新安排群落，从而重新安排物种之间的相互作用。调查人员将回答两个基本问题。首先，他们将确定拮抗剂（松松鼠）的存在和缺失如何影响互惠互动，以及这反过来如何影响松林的发展。其次，他们将验证一个假设，即鸟类在松树上的传播只在没有松松鼠的情况下才会进化。这项研究的广泛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，由于一种引起白松水疱锈病的侵入性病原体，针叶松和白皮松都在急剧下降。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，这些因素在这个系统中是至关重要的，因为如果它们依赖于自然更新，长期的保护工作可能会更成功。更好地了解松树的补充是很重要的，因为这两种松树和胡桃松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，至少培养一名博士生。

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.