Document Type
Thesis
Date of Degree Completion
Summer 2025
Degree Name
Master of Science (MS)
Department
Biology
Committee Chair
Dr. Alison Scoville
Second Committee Member
Dr. Kristina Ernest
Third Committee Member
Dr. Megan Walsh
Abstract
Clark’s nutcrackers (Nucifraga columbiana) and whitebark pine (Pinus albicaulis) share a highly adapted mutualistic relationship that sustains subalpine whitebark pine ecosystems, which are under threat from increased frequency, severity, and extent of wildfire due to recent climate change. Whitebark pine is not well-adapted to survive extreme wildfire events, and post-fire regeneration likely depends on caching by nutcrackers. However, little is known about nutcracker behavior within burned whitebark pine habitat. This study investigated drivers of Clark’s nutcracker occupancy following fire in the Cascade Mountains of Washington State by evaluating the degree to which local and landscape-scale habitat metrics predict nutcracker presence, as detected via calls recorded with autonomous recording units (ARUs). Twenty-eight ARUs were randomly deployed within severely burned, moderately burned, and unburned whitebark pine habitat above 1828 m, in four fire footprints in the Okanogan-Wenatchee National Forest, from June 26 until October 5, 2024. Results from a dynamic occupancy model provided evidence that nutcrackers were highly likely to occupy all sites, from unburned to severely burned at the local scale, when most area within a 3-km radius contains a mosaic of burned and unburned whitebark pine habitat. As the availability of either burned or total whitebark pine habitat within a 3-km radius decreased, nutcrackers showed a stronger preference for locally burned sites, especially during the early to late summer. These occupancy patterns suggest that burned habitat provides an important but as yet unidentified resource during the summer, prior to whitebark pine cone maturation. In addition, our results suggest that nutcrackers are available to potentially facilitate post-fire whitebark pine regeneration in this region as long as fire footprints contain a mosaic of burned and unburned habitat.
Recommended Citation
Sacco, Ashley M.; Scoville, Alison; and Schaming, Taza D., "Clark’s nutcracker (Nucifraga columbiana) occupancy in a post-fire whitebark pine (Pinus albicaulis) ecosystem" (2025). All Master's Theses. 2172.
https://digitalcommons.cwu.edu/etd/2172
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