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by Larry

July, 2013

Sagebrush Ecosystems' Sayonara?

Oddly enough, sagebrush habitats are disappearing. Across vast stretches of the American west, sagebrush has been a prevailing aspect of the landscape, one supporting a wide array of fauna and other flora for far longer than our kind has been around. While the rate of change varies with different locales, that dominance is now ending. In one isolated habitat and form or another, sagebrush varieties (Artemisia arbusula, A. nova, A. cana, A. tridentata [big sagebrush], etc.) are likely to continue to exist. However, as long-gone sagebrush habitat creatures such as the prehistoric camels, mastodons, and giant sloths demonstrate, depending on which species they support, the character of these ecosystems can change radically from time to time.

Moreover, the combined effect of unnaturally hot and destructive fires, pollution, overgrazing, erosion, global warming related climate changes, off-road vehicle use, non-native invading floral species, drilling, or agricultural and urban development is to reduce many formerly huge sagebrush areas to isolated remnants, threatening their complete loss as well as that of the many associated species they sustain.

Despite sagebrush predating the present form of the Great Basin, the territory of this set of plants is now roughly that of the massive feature, covering approximately half of the western United States, though in places sagebrush plants extend into similar geographical areas of the Rocky Mountains and adjacent basins and plateaus.

The Great Basin is a gigantic arid region of some 190,000 square miles, believed to have had its origin in volcanic activity perhaps 30,000,000 years ago and further affected by subluxation, the formation of underground seas, their later exposure on the surface, major drainages, and the accumulation of mineral content.

Taos, NM, area sagebrush and peaks (spring, 2011)
Though sagebrush varieties and their related ecosystems are millions of years old, with fossils confirming their presence at least as far in the past as the late Miocene (roughly 10,000,000 to 5,000,000 years ago), recently they are under stress not only from direct actions by our species but also due to encroachment by invasive species we have intentionally or inadvertently introduced, especially juniper woodlands, fir trees, cheatgrass, and several other non-native annual grasses. Just as alterations in the sea that threaten reef corals have implications for the preservation of many other reef species, so hundreds of animal and plant species, among them the burrowing owl, northwest Hesperian snail, Washington ground squirrel, pallid bat, greater sage grouse, Dwarf skullcap, Great basin spadefoot toad, Lemhi birdtongue, sage thrasher and sage sparrow, pygmy rabbit, Brewer's sparrow, sagebrush lizard, pronghorn, and sagebrush vole, owe their survival to healthy sagebrush habitats. Mule deer and elk at times also graze on sagebrush and so would be the worse for its having substantially diminished range.

Prior to the arrival of Europeans in the Western hemisphere, Amerindians had multiple uses for sagebrush, for instance, for fuel, medicine, teas, purification rituals, and so forth. Other plants in the sagebrush ecosystem provided wood for bows, special rinses for hair washing, and chokeberries to eat. A sagebrush habitat also offered the Indians food via the abundant fauna species.

Occidentals, however, have generally treated sagebrush and related flora as weeds, perhaps mainly because cattle do not eat them, they can interfere with crop production, and conservationists seek to preserve them at the expense of unrestrained energy development.

A short-term, strictly utilitarian outlook may doom much of the recent habitat of the North American west. It is difficult to see how we shall ultimately be better off with the simpler ecosystem that may replace that now characterized by the sagebrush and its many associated flora and fauna species. However, no doubt in time old and new vegetation and creatures will adjust or evolve to the juniper and grassland areas which formerly supported sagebrush and its milieu. Ultimately, everything changes. It would be fascinating to see how the west of our nation may look a thousand, ten thousand, or a hundred thousand years hence and how or if we ourselves have adapted to the alterations we have helped create.

Primary sources:

Sagebrush Steppe Treatment Evaluation Project. in SageSTEP, last updated in 2013;

Sagebrush: Species of the Week. in Elizabeth Enslin, July 22, 2009;

Sagebrush Steppe. in Sawtooth Botanical Garden, last updated in 2009;

Sagebrush Showdown. Keith Kloor in Audubon Magazine, last updated with the May-June issue, 2011.

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