Sagebrush & Desert Shrublands

Sagebrush, Hanna Basin
Sagebrush, Hanna Basin
Photo by Jay Lillegraven
lizard
Horned lizard
Photo by Ken Driese
desert
Desert shrubland near Boar's Tusk
Great Divide Basin

The content of this page supplements chapters 7 and 8 in Mountains and Plains: The Ecology of Wyoming Landscapes (2nd edition).  Readers with questions are encouraged to contact us.

Sage grouse

Several excellent articles on sage grouse conservation appeared in the summer 2015 issue of Western Confluence, which can be viewed at  westernconfluence.org

Would fertilizing sagebrush benefit deer?  This question was addressed by Nicole Korfanta and her co-authors in a 2014 paper in the Wildlife Society Bulletin (DOI: 10.1002/web.519).  They concluded that there are numerous risks, that "potential benefits are short-term, uncertain, and expensive to achieve," and that "the practice of sagebrush fertilization may pose a net conservation cost." 

Invasive plants in sagebrush

Manier, D. J., C. L. Aldridge, M. O'Donnell, and S. J. Schell. 2014. Human infrastructure and invasive plant occurrence across rangelands of southwestern Wyoming, USA. Rangeland Ecology and Management 67:160-172.  [In this study, the distributions of weedy plants were examined in relation to the distance to roads, railroads, pipelines, and oil and gas well pads.  For a recent popular discussion of invasive species in North America, see Time magazine (July 28, 2014).]

Anderson, J, and R.S. Inouye. 2001. Landscape scale changes in plant species abundance and biodiversity of a sagebrush steppe over 45 years. Ecological Monographs 71:531-558. [They concluded that "adequate cover of native species can render these semi-arid communities more resistant to invasion.]

Cheatgrass as forage

One reader asked if cheatgrass (Bromus tectorum), also known as downy brome and drooping brome, is considered a source of forage for domestic livestock.  Definitely.  Cheatgrass is a good forage before it sets seed, but there are still the negative effects of crowding out native species and increasing flammability and fire frequency above the norm, which can reduce the abundance of big sagebrush and some other desirable plants.

Notably, cheatgrass is an annual.  Therefore, much of the plants energy and nutrients end up in the seeds.  That’s the best survival strategy for an annual plant.  Seed germination usually occurs in the fall and the plant grows rapidly in the spring and early summer.  During the relatively short time that the plant is green, the plant is very nutritious and livestock like it.  Some livestock producers even increased their herd sizes because it grew so abundantly.  A down side of annual plants, however, is that their abundance varies greatly from year to year.  A rancher could not depend on it from one year to the next, hence the name “cheatgrass.”  

The big problem with cheatgrass is that it becomes abundant by early summer before drying out and becoming very flammable.  Grasslands and sagebrush-dominated shrublands are characterized by periodic fires, and many of the plants benefit from such fires, but with cheatgrass the fires become so frequent that some native plants cannot survive (e.g., big sagebrush, which lacks the ability to sprout from the burned stump, unlike many of the other natives).  This is discussed on pages 122-124 of the 2nd edition.  

Also, because cheatgrass is a winter annual and produces an extensive root system, which gives it a head start in the spring, it out-competes some of the native plant species for water.  The native species therefore become less abundant.  That’s why it’s referred to as an invasive plant (though not all introduced plants are invasive).  This, combined with more frequent fires, causes a decline in biological diversity and leads many ranchers to have a negative attitude toward this plant despite the fact that it has high forage value for a short time during some summers.

For more information, see
http://www.fs.fed.us/database/feis/plants/graminoid/brotec/all.html#Introductory

Additional synthesis papers on sagebrush ecosystems

Entwistie, P.G., A.M. DeBolt, J.H. Kaltenecker, and K. Steenhof, compilers. 2000. Proceedings: Sagebrush Steppe Ecosystems Symposium. Bureau of Land Management Publication No. BLM/ID/PT-001001+1150, Boise, Idaho, USA.

Smith, S.D., R.K. Monson, and E. Anderson. 1997. Physiological ecology of North American desert plants. Springer-New York.

Cushion Plant Community
Cushion plants are common on exposed ridges in desert shrublands

Photo by Charmaine Delmatier.