Antelope bitterbrush and mule deer

Authors: Clements, Darin - Charlie

Submitted to: The Progressive Rancher
Publication Type: Popular Publication
Publication Acceptance Date: 3/21/2023
Publication Date: 4/4/2023
Citation: Clements, D.D. 2023. Antelope bitterbrush and mule deer. The Progressive Rancher. 23(4):10-13.

Interpretive Summary:

Technical Abstract: Woody members of the Rosaceae family were never dominant in the Intermountain vegetation, but fossil records indicate that they were a significant understory in forests and woodlands. From these ancestor populations evolved a few species that play important roles in current temperate desert environments because of their nutritional value to domestic livestock and wildlife, especially antelope bitterbrush, desert bitterbrush and cliffrose. It took a long time for brush species and the browse they produce to be recognized as an important component of rangeland production. The concept of shrubs being an important part of the forage resources of western rangelands received vital stimulation in 1931 when William A. Dayton, early plant ecologist with the U. S. Forest Service, published Important Western Browse Plants, in which Dayton pointed out that despite the alluded bitter taste of antelope bitterbrush, this browse species is one of the most important browse species occurring on western rangelands, and some cases the most single browse species in the locality. Even though antelope bitterbrush is more widely known for its' nutritional fall and winter forage assets, the shrub is palatable all seasons and is preferred by all classes of domestic large animals, except horses. Starting about 1920, bitterbrush and mule deer became synonymous, and for much of the range of bitterbrush species, mule deer are the most important native large herbivore. Wildlife biologist, C. M. Aldous reported that before 1929, mule deer were not considered abundant anywhere in the Intermountain Area, but afterwards their populations exploded. Aldous conducted utilization studies on key winter browse species and determined the utilization of antelope bitterbrush average 51% of the current annual growth, while the closely related shrub cliffrose averaged 38% utilization. This study was one of the first to report crude protein, crude fat, and fiber content of antelope bitterbrush. The significant loss of antelope bitterbrush on many mule deer ranges due wildfires is well noted. This in combination with aging antelope bitterbrush stands and lack of recruitment of new seedlings to sustain the antelope bitterbrush population continues to be of great concern as mule deer populations struggle to have adequate nutrition on transitional and winter ranges throughout the Great Basin. Active restoration of antelope bitterbrush plants will need to be conducted to improve stand age, stand vigor and future recruitment of antelope bitterbrush needed to sustain antelope bitterbrush stands, improve much needed nutrition provided by this species and ultimately provide critical habitat for mule deer and other wildlife species dependent on the nutritional value of rangelands.