Several years ago I accompanied some U.S. Forest Service staff on a horseback inspection of a livestock grazing allotment located in the arid Superstition Mountains of the Tonto National Forest in central Arizona. As we neared a muddy stock tank perched on a chaparral-covered hill we scared off several mule deer that were taking a drink. The District Ranger turned toward me in his saddle and told me how glad he was that livestock were allowed to graze public lands, because the deer would be scarce if there weren’t any livestock waters.
The theory that the wildlife species native to the West’s arid ecosystems depend upon livestock waters for their survival is a popular one. Many federal land managers are willing to believe it. Their environmental assessments of grazing allotment management plans often warn that eliminating livestock grazing would harm local wildlife populations because the livestock waters wouldn’t be maintained.
Most ranchers also seem to believe it, and they frequently offer it in defense of livestock grazing on public lands. I’ve even had ranchers tell me there was hardly any wildlife in Arizona before ranchers arrived and “improved” the land, which is, of course, ridiculous (Davis 1982).
The idea that wildlife depend upon livestock waters is so prevalent there’s a conservation group called the Arizona Desert Bighorn Sheep Society that works with the Arizona Game and Fish Department (AGFD) to try and increase bighorn sheep numbers by constructing permanent water holes in the Sonoran desert.
Statewide, the AGFD maintains more than 725 wildlife waters at an estimated annual expense of about $400,000.
Despite all this, there’s surprisingly little scientific evidence to support this belief – and much that contradicts it. Even long-time proponents of livestock waters question their effectiveness (Brown 1997; Krausman 1997). For instance, a review of the AGFD bighorn sheep water development program (Broyles 1995) conducted in the Cabeza Prieta National Wildlife Refuge concluded, “It has not been shown that these developments are necessary, beneficial, or without harmful side effects.”
Another study conducted in southern New Mexico (Burkett and Thompson 1994) compared wildlife populations at 20 sites that had man-made waters with the same number of similar sites lacking permanent surface water. They found that, “definitive effects of artificial water sources on native wildlife species were not detectable.”
And another study conducted in Arizona’s Sonoran Desert (Krausman and Etchberger 1995) looked at desert mule deer and bighorn sheep populations in the area of the Central Arizona Project canal before and after its construction. They found that, “additional water was not important to the deer or sheep populations.” And a more recent study of mule deer distribution in arid environments (Marshall 2006) found that forage quality was the most important habitat component, and additional livestock waters had little effect.
There are also studies suggesting livestock waters may have negative effects upon native wildlife. For example, they may provide habitat for invasive fish, bullfrogs, and crayfish that can get washed into streams during floods (Sponholtz 1997), and non-native species are the primary factor in the decline of native fish and amphibian species in the West (Simms 1997).
Building new livestock waters in upland areas is often justified by claiming they will lure cattle away from ecologically important riparian bottomlands. But cattle are bred to be lazy critters and are unlikely to climb a sunny hill in the heat to get a drink when the they can stay in the shade of a tree along a stream. Research has shown (Carter 2017) that upland water sources in the arid West don’t attract enough cattle out of riparian areas to allow these important habitats to achieve full ecological health.
The construction of new livestock waters is also used to improve livestock distribution on the uplands. The idea is to spread out the livestock more evenly to reduce overgrazing in areas where the animals like to congregate. It can help overused areas recover from overgrazing, but it can also bring the negative ecological impacts of grazing to new areas that were historically too dry for livestock use (McAuliffe 1997).
Still, the idea that more water means more wildlife sounds intuitively good. It’s an easy concept for hunters and hikers to believe because they know one of the best places to spot wildlife is around water holes. But just because animals congregate around water holes doesn’t mean they’re relying on that water source for their survival. For example, how often have you stopped to take a drink from a water fountain just because it was convenient?
But what about all of those biologists warning us the majority of the West’s wildlife depend, in some way, upon riparian areas for their survival? Livestock waters rarely support significant amounts of riparian habitat. Many of them are so trampled by cattle they are considered ecological sacrifice zones.
Numerous studies have shown it’s the amount and quality of suitable habitat that has the most influence upon wildlife populations. For instance, AGFD research showed that Gambel’s quail (Callipepla gambelli) don’t need surface water, and the quantity and quality of forage was the most important limiting factor on quail populations (Gallizioli 1961). In other words, water is just one component of wildlife habitat, and most Western U.S. wildlife species are adapted to its scarcity.
Of course, there are always exceptions. Elk, for instance, behave much like cattle and livestock waters constructed by ranchers have helped them inhabit hotter and drier areas where they were historically scarce or nonexistent. It’s ironic, because ranchers often complain that local elk populations need to be reduced because they’re competing directly with their cattle for available forage.
The bottom line is the ecological effects of building livestock waters should be objectively considered. Sufficient vegetation to provide quality cover and forage appears to be more important than surface water for most arid land wildlife species. New livestock waters are very expensive and on public lands they are typically built with public funds. In most situations, it would be cheaper for the taxpayers if federal land managers would simply cut permitted livestock numbers to achieve natural resource goals.
Brown, D.E. 1997. Water for Wildlife: Belief Before Science. Symposium on Environmental, Economic, and Legal Issues Related to Rangeland Water Developments, November 13-15. Arizona State University College of Law, Tempe, AZ.
Broyles, B. 1997. Reckoning Real Costs and Secondary Benefits of Artificial Game Waters in Southwestern Arizona. Symposium on Environmental, Economic, and Legal Issues Related to Rangeland Water Developments, November 13-15. Arizona State University College of Law, Tempe, AZ.
Burkett, D.W., and B.C. Thompson. 1994. Wildlife Association with Human-Altered Water Sources in Semiarid Vegetation Communities. Conservation Biology 8(3):682-690.
Carter, J., Catlin J.C., Hurwitz, N., Jones, A.L., and J. Ratner. 2017. Upland Water and Deferred Rotation Effects on Cattle Use in Riparian and Upland Areas . Rangelands Volume 39 (3-4): 112-118.
Davis, G. P. 1982. Man and Wildlife in Arizona. Arizona Game and Fish Department, Phoenix, AZ.
Gallizioli, S. 1961. Water and Gambel quail. Arizona Game and Fish Department Bulletin. Phoenix, AZ.
Krausman, P. R., and R.C. Etchberger. 1995. Responses of Desert Ungulates to a Water Project in Arizona. Journal of Wildlife Management 59(2):292-300.
Krausman, P.R., and B. Czech. 1997. Water Developments and Desert Ungulates. Symposium on Environmental, Economic, and Legal Issues Related to Rangeland Water Developments, November 13-15. Arizona State University College of Law, Tempe, AZ.
Marshal, J.P., V. C. Bleich, P. R. Krausman, M. L. Reed, and N. G. Andrew. 2006. Factors Affecting Habitat Use and Distribution of Desert Mule Deer in an Arid Environment. Wildlife Society Bulletin 34(3):609-619.
McAuliffe, J.R. 1997. Rangeland Water Developments: Conservation Solution or Illusion? Symposium on Environmental, Economic, and Legal Issues Related to Rangeland Water Developments, November 13-15. Arizona State University College of Law, Tempe, AZ.
Simms, J. 1997. Some Effects of Stock Tanks on Aquatic Biodiversity in Arizona Streams. Symposium on Environmental, Economic, and Legal Issues Related to Rangeland Water Developments, November 13-15. Arizona State University College of Law, Tempe, AZ.
Sponholtz, P.J., D.C. Redondo, B.P. Deason, L.M. Sychowski, and J.N. Rinne. 1997. The Influence of Stock Tanks on Native Fishes: Upper Verde River, Arizona. Symposium on Environmental, Economic, and Legal Issues Related to Rangeland Water Developments, November 13-15. Arizona State University College of Law, Tempe, AZ.