The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Monday, January 28, 2008 - 2:40 PM
Predicting Feeding Site Selection of Mule Deer in Foothill and Mountain Rangeland Habitats
Josh A. Bilbao, Tracy K. Brewer, and Jeffrey C. Mosley. Department of Animal and Range Sciences, Montana State University, Bozeman, MT 59717
Identifying areas on the landscape selected by mule deer (Odocoileus hemionus) for foraging and the characteristics of selected feeding sites is a crucial step in managing mule deer and its habitat. Rising mule deer populations in many foothill and mountain rangeland habitats are making mule deer habitat management increasingly important. In this study, we developed and validated a feeding site selection model that incorporates the effects of eight habitat variables that may influence feeding sites chosen by mule deer in winter and spring, including aspect, elevation, slope, level of previous cattle grazing, and distances to cover, agricultural fields, roads, and water. Data collected on 3 study sites in northwestern Wyoming from Summer 1999-Spring 2001 was used for model development and data from Summer 2001-Spring 2003 was used for temporal validation. Data collected on 2 study sites in west-central Montana from Summer 2001-Spring 2003 was used for temporo-spatial validation. Habitat use by mule deer was monitored with monthly and bi-monthly (model development and validation, respectively) aerial surveys from a fixed-wing aircraft along 0.8-km transects. To describe the habitats available to mule deer within the study area and determine if they were using habitat in proportion to its availability, the habitat variables included in the model were also characterized on 200 random points within each study site. For model development, resource selection functions were developed for winter, spring, and combined seasons using binary logistic regression in a stepwise backwards-approach to determine which habitat attributes influence mule deer feeding site selection. Model validation was conducted using the resource selection functions created during model development and analyses were conducted similarly. Final results will be presented.