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.
