By Jeff Burgess © 1996
A couple of years ago I accompanied some U.S. Forest Service staff on a horseback inspection of a livestock grazing allotment located in the eastern Superstition Mountains of Arizona's Tonto National Forest. As we neared a muddy cattle 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 deer would be scarce if there weren't any livestock waters.
The theory that wildlife species native to the West's arid ecosystems depend upon livestock waters for survival is a popular one. It seems many federal land managers believe it. Many of their environmental assessment's have warned that eliminating livestock grazing could result in local wildlife populations suffering from the lack of livestock waters.
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 1300 member conservation group, called the Arizona Desert Bighorn Sheep Society, that works with the state's Game and Fish Department (AGFD) to try and increase 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 are now questioning their effectiveness (Brown 1997; Krausman 1997). For instance, a recent review (Broyles 1995) of the bighorn sheep water development program AGFD has conducted in the Cabeza Prieta National Wildlife Refuge during the last 50 years concluded, "It has not been shown that these developments are necessary, beneficial, or without harmful side effects."
Another study recently 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."
Another recent study conducted in the western Arizona 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."
In addition to questioning their utility, there are studies suggesting livestock waters may have negative effects upon native wildlife. For example, they may provide habitat for exotic fish, bullfrogs, and crayfish that can get washed downstream during floods (Sponholtz 1997), and introduced species are the primary factor in the decline of native fish and amphibian species in the West (Simms 1997).
Also, the construction of new livestock waters can lure cattle into areas that were historically too dry for them (McAuliffe 1997). Range managers call it "improving livestock distribution," and they argue that spreading out the livestock more evenly can help a region recover from overgrazing. But creating new livestock waters still brings the negative ecological impacts of grazing to new areas, even when the grazing is managed.
Sometimes, new livestock waters are built to help protect important riparian areas from cattle. By giving livestock an alternative place to get a drink, the stream can more easily be fenced to exclude them. This protection gives the riparian habitat a good chance of returning to proper functioning condition. In these cases, it could be argued that livestock watering sites clearly benefit local wildlife. But they're not doing it by improving the quality of the wildlife habitat in the places they're built, they're doing it by moving cattle away from other places that need relief.
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 an animal stops to take a drink, doesn't necessarily mean it's relying on that particular water for its survival. For example, how often have you stopped to take a drink from a water fountain when you weren't really thirsty?
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? Well, just because there's water doesn't mean there's riparian habitat. The fact is, few livestock waters support significant amounts of riparian habitat. Many of them are so trampled by cattle they are considered ecological sacrifice zones.
Besides, numerous studies have shown it's the amount and quality of suitable habitat that has the most influence on wildlife populations. For instance, as long ago as 1962 the AGFD completed research that showed Gambel's quail (Callipepla gambelli) don't need standing water, and that quail numbers in areas without it can be greater than those in adjacent areas with it. They discovered the quantity and quality of forage was the most important limiting factor on quail populations. In other words, water is just one component of wildlife habitat and most Western wildlife species are adapted to its usual scarcity.
Of course, there are always exceptions. Elk, for instance, behave much like cattle and livestock waters constructed by ranchers have helped them inhabit 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 livestock waters should be objectively considered. In some situations, new livestock waters can help facilitate riparian habitat recovery, or improve livestock distribution on upland areas. But even then, constructing the necessary waters and fences is expensive and, on public lands, they are typically built with government funds. In many situations, it would be cheaper for the taxpayers if federal land managers would simply cut permitted livestock numbers to achieve these goals.
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NOTE: Previous versions of this article were published in the Arizona Riparian Council newsletter, the Canyon Echo, and Arizona Wildlife News.