Graduation Year

2025

Graduation Month

May

Document Type

Thesis

Degree Name

Bachelor of Science

School or Department

Forestry and Conservation

Major

Environmental Science and Sustainability

Faculty Mentor Department

Ecosystem and Conservation Sciences

Faculty Mentor

Cara Nelson

Keywords

whitebark pine, clark's nutcracker, blister rust, pinus albicaulis, nucifraga columbiana, forest stand structure

Subject Categories

Forest Biology

Abstract

Whitebark pine (Pinus albicaulis), a keystone species of high-elevation ecosystems of western North America, is threatened with extinction due to disease (Blister rust), pests (Mountain pine beetle), and climate change. Regeneration of the species depends nearly exclusively on the seed-caching behavior of Clark’s nutcracker (Nucifraga columbiana, Family Corvidae). Because of this, conservation of whitebark ecosystems requires restoring stand structures that favor nutcrackers. Although there are increasing numbers of studies on the relationship between nutcrackers and whitebark pine, findings have not yet been synthesized, limiting knowledge for application to management. I did a systematic literature review to answer the following questions: 1) How do stand conditions affect nutcracker visitation; 2) over what distances do nutcrackers disperse seed; 3) in what types of microsites do nutcrackers most frequently cache seeds. I also assessed 4) whether responses to these questions varied by geographic region. For each of the 96 articles I found in a Web of Science search, I collected information on the geographic location of the study, what kind of forest stands were studied, how often nutcrackers visited, how far they dispersed seeds, and what types of stands they used for caching. There were a total of 18 articles that addressed the relationship between stand structure and nutcracker visitation. Visitation was over 12 times higher in southern, low-rust forests compared to northern latitude sites, where cone production and seedling density were also much lower. I expect to find that nutcrackers prefer more open stands with healthy cone-producing trees, and that they cache seeds across a mix of open areas, burned forests, and mixed conifer stands. Understanding drivers of nutcracker visitation and seed dispersal can help land managers restore whitebark pine forests in ways that support both the trees and nutcrackers. This work matters because whitebark pine is critical for wildlife and water systems, and its survival depends on this unique bird-tree partnership.

Honors College Research Project

1

GLI Capstone Project

no

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