Fire, red squirrels, whitebark pine, and Yellowstone grizzly bears

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Whitebark pine (Pinus albicaulis) habitats are important to Yellowstone grizzly bears (Ursus arctos) as refugia and sources of food. Ecological relationships between whitebark pine, red squirrels (Tamiasciurus hudsonicus), and grizzly bear use of pine seeds on Mt. Washburn in Yellowstone National Park, Wyoming, were examined during 1984-86. Following large-scale fires in 1988, we repeated the study in 1995-97 to examine the effects of fire on availability of whitebark pine seed in red squirrel middens and on bear use of middens. Half of the total length of the original line transects burned. We found no red squirrel middens in burned areas. Post-fire linear-abundance (no./km) of active squirrel middens that were pooled from burned and unburned areas decreased 27% compared to pre-fire abundance, but increased in unburned portions of some habitat types. Mean size of active middens decreased 54% post-fire. Use of pine seeds by bears (linear abundance of excavated middens) in pooled burned and unburned habitats decreased by 64%, likely due to the combined effects of reduced midden availability and smaller midden size. We discourage any further large-scale losses of seed producing trees from management-prescribed fires or timber harvesting until the effects of fire on ecological relationships in the whitebark pine zone are better understood.

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Publication type Article
Publication Subtype Journal Article
Title Fire, red squirrels, whitebark pine, and Yellowstone grizzly bears
Series title Ursus
Volume 11
Year Published 1999
Language English
Publisher International Association for Bear Research and Management
Publisher location New York, NY
Contributing office(s) Forest and Rangeland Ecosystem Science Center, Northern Rocky Mountain Science Center
Description 8 p.
First page 131
Last page 138
Public Comments Form a Special Issue: A Selection of Papers from the Eleventh International Conference on Bear Research and Management, Graz, Austria, September 1997, and Gatlinburg, Tennessee, April 1998
Country United States
State Wyoming
Other Geospatial Mount Washburn
Online Only (Y/N) N
Additional Online Files (Y/N) N
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