Spring Livestock Grazing Affects Crested Wheatgrass Regrowth and Winter Use by Mule Deer

Abstract

Areas grazed and ungrazed by cattle in spring were compared for regrowth of crested wheatgrass on a big sagebrush-grass range. Overwinter utilization of crested wheatgrass by tame mule deer and their grazing area preferences were assessed under 3 snow cover conditions-snow free, partial, and complete. Results showed regrowth production was usually higher on areas previously ungrazed by livestock. Overwinter utilization of crested wheatgrass by deer was determined to be greater on ungrazed areas in both percentage of available grass used and weight per unit area consumed. Thus, interference from cured growth limiting green grass availability was more than compensated by increased production. The percentage of grass in the diet was generally higher on areas ungrazed by cattle, and deer preferred these areas under snow free and partial snow cover conditions; no preference was exhibited during complete snow cover. Recommendationsfor livestock grazing of seeded, foothill ranges where deer use is critical are discussed. Few winter rangelands are used exclusively by either domestic or wild ungulates, rather, use is usually sympatric, but not necessarily simultaneous. Critical foothill ranges used by mule deer (Odocoileus hemionus) in the winter are typically grazed by livestock during spring, fall or both. As demands for and values of wildlife recreation increase, managing these critical ranges primarily for wildlife habitat becomes monetarily and socially justifiable (Hendee 1974, Wennergren et al. 1977). The purpose of this study was to determine the influence of spring livestock grazing on a big sagebrush (Artemisia tridentata)crested wheatgrass (Agropyon desertorum) range on overwinter forage utilization and area choice by mule deer.