Overgrazing: More Deadly Than Any Hunter
By Steve Gallizioli
Originally published in Outdoor Arizona, October 1977, pp. 24-26, 31.
People today are more aware of, and more concerned about, wildlife and wildlife problems than ever before. To a large degree television gets the credit for arousing the interest of so many people. It must also accept the blame for the misinformation that has been dispensed via the TV screen, much of it having to do with the causes for declining animal populations. The networks seem to have been more interested in promoting the idea that hunters are to blame for the plight of endangered species than in presenting the real issues. For most species, the cause is more likely to be restricted or impoverished habitat due to any one of dozens of man's activities.
The disastrous but bloodless consequences of habitat destruction are simply not sufficiently dramatic to arouse people. The end product of habitat destruction, the elimination of entire populations of animals, is too distantly removed from the habitat disruption itself.
This is even more true of the habitat disruption that results from overgrazing--a particularly insidious form of habitat damage--because it takes place slowly, over a span of years. Many people got their dander up over the threatened elimination of the riparian habitat in the Orme Dam site, yet few are able to appreciate the consequences of the overgrazing that has prevailed over most of the lands near Orme Dam for the past 75 years or more.
Overgrazing by livestock is doing infinitely more damage to Arizona's wildlife populations than Orme Dam could possibly do. (No Virginia, I am not a supporter of Orme Dam. Quite the contrary in fact.) This reservoir would flood a paltry few thousand acres, while overgrazing has seriously lowered the carrying capacity for wildlife on millions of acres. Because virtually all wildlife habitats are grazed by livestock, and because overgrazing (the practice of running more livestock than the forage can support) is so widespread and has severely degraded such a vast acreage of habitat for so many wildlife species, it has to rank as the single more important limiting factor for wildlife in Arizona today.
A major problem in the public's failure to become concerned about overgrazing is the fact that the practice does not quickly eliminate wildlife habitat; it, instead, slowly degrades it. Over time the quality of the habitat, the environment in which an animal lives, is lowered. One might look on it as equivalent to the gradual conversion of a choice neighborhood into a slum. Chronic overgrazing promotes wildlife slums. A big difference is that, unlike the artificially supported populations in our human slums, animal species are more drastically affected by the impoverishment of their environment.
For the most part, wildlife is not totally eliminated by overgrazing. Overgrazed ranges will usually continue to support deer, javelina, quail, cottontails, curve-billed thrashers, packrats, Gila monsters, desert tortoises and many others. But there won't be as many--the reduction in numbers being related to the severity of the range abuse and the tolerance of the individual wildlife species to habitat disturbance. Some will be more affected than others, but seldom is overgrazing carried to such extremes that habitat damage is complete and a species is wiped out. But the fact that even this can happen is evidenced in the story of the masked bobwhite of southern Arizona.
This strikingly plumaged near-relative of the Eastern bobwhite was removed from the Arizona scene about the turn of the century. It happened when one of the periodic droughts, a natural feature of desert regions, struck Arizona in the late 1890s. The historical record shows that southern Arizona ranges at the time were flooded with literally hundreds of thousands of cattle. When the drought hit, untold thousands of cattle starved to death--but not before they had denuded the range of vegetation.
The extreme overgrazing destroyed the habitat for the bobwhite: when the habitat went so too did the bobwhite. Its call was not heard again until recently, when the progeny of masked bobwhite trapped in Sonora and propagated at Patuxent, Maryland, were released in historic habitat in the Altar Valley southwest of Tucson (under a cooperative program between the U.S. Fish and Wildlife Service and the Arizona Game and Fish Department). Overgrazing is still more the rule than the exception in the Altar Valley, although conditions have improved somewhat. Whether the habitat has recovered enough in the past 75 years to again support this species is uncertain. The results of the restocking efforts to date have not been promising.
While many people are of the opinion that overgrazing is a practice that stopped long ago when management of public lands came under the control of state and federal land management agencies, the facts are something else entirely. In the Southwest at least, and particularly here in Arizona, overgrazing has actually worsened in many areas during the past 25-30 years. For the most part, what improvement there has been has taken place on the National Forests. Grazing lands administered by the Arizona State Land Department and the Bureau of Land Management are in a generally sorry state of affairs.
Even on the National Forests there is still room for much improvement, but this agency may now be making an effort to bring livestock numbers in line with what Arizona ranges can support. And a real effort is long overdue. The history of grazing on National Forest lands has been one of "too late and too little." Because of the long, drawn-out appeal procedures available to ranchers faced with a serious reduction in livestock numbers on their overgrazed allotments, a forest supervisor often felt he had to compromise, settling for a smaller cut in livestock numbers--one that the rancher would agree to, rather than pressing the issue and going through a long appeal process. Perhaps settling for "half a loaf" today instead of pressing for the allotment cut that the supervisor knew was necessary seemed the thing to do. Such a tactic, however, is one of the reasons so many ranges have continued to deteriorate, despite the reductions in stocking levels that were indeed made.
Sadly, settling for less than what was actually called for only served to slow range degradation. It didn't stop the process. Choice forage plants continued to suffer and worthless weed species continued to increase as the good ones were killed off by overuse. Soil erosion continued to grind away the precious few inches of topsoil and wildlife habitat continued to suffer.
I sometimes hear apologists for range abuse argue that overgrazing does not so much degrade or destroy wildlife habitat as that it alters it, making it more suitable for some species as it makes it less suitable for others. I must admit there is a kernel of truth in the argument, particularly as it applies to the early stages of overgrazing. For the most part, however, the species that are favored by overgrazing are not, by most standards, as desirable as those that are eliminated.
Most people would not consider large numbers of jackrabbits and gophers a fair exchange for herds of antelope and coveys of scaled quail. And even the rabbits and rodents that might thrive under the early stages of overgrazing themselves suffer as the range abuse continues.
Some species are more intolerant of range abuse than others and more likely to be adversely affected by it. Much depends on whether an animal does best on habitat that is in what biologists call a "climax" state. "Climax" is simply that stage which a disturbed area reaches after many years, if no other disaster strikes. For example, when "climax" spruce forest burns, the area will slowly go through a series of phases over many years until it again supports a stand of mature spruce. Different species of animals will occupy the area as it goes through these successional phases.
Desert grassland is another type of climax formation, and the masked bobwhite was a bird associated with this habitat type. Unfortunately for the masked bobwhite, the consequences of severe overgrazing in this habitat were much more disastrous than a burn. A fire in grassland generally burns off the above-ground portions of the vegetation. The burned area will quickly recover and support a stand of grasses within a year or less. Prolonged overgrazing, however, weakens and eventually kills the perennial grasses, the most important component of grassland. Once the perennial grasses are gone it is almost impossible to restore them even if the area is protected completely against grazing--which rarely happens. The Arizona Game and Fish Department's Three Bar Wildlife Area, however, is one such area that has been protected from cattle for more than 30 years. Yet, in spite of the long period of complete protection, the perennial grasses have never been restored to most of the area and many of the deep erosion gullies started by the heavy overgrazing 40-50 years or more ago have not even begun to heal.
Antelope and bighorn sheep also do best under climax conditions. Mule deer, on the other hand, fare better under some degree of disturbance. Because heavy grazing over the years has eliminated the original perennial grass stands from many areas, those species that do best in grassland climax have suffered most from this type of land abuse.
Less than 100 years ago we had large herds of antelope roaming the desert grasslands of southern Arizona, including much of the country near Oracle Junction. Overgrazing has converted the Oracle Junction area from productive desert grassland to low value desert scrub. As its preferred habitat was destroyed, the antelope gradually disappeared. There hasn't been an antelope seen in that locality in 20 years or more.
Scaled quail also thrived in the same habitat as the southern Arizona antelope. A few scalies continue to hang on near Oracle Junction; but, as conditions worsen, it is only a question of time until they too will disappear.
Desert bighorn sheep, another climax species, were once so abundant in Arizona that local Indians relied on them for the major part of their protein. One of the most amazing bits of evidence of bighorn sheep abundance was the report of a witness in the 17th century of a veritable mountain of bighorn sheep horns in an Indian village near Tucson. The observer estimated there were some 100,000 sets of horns in the pile! Even if the report is exaggerated by 50 percent or more, it would still suggest an incredible abundance of bighorns to support hunting on such a scale. Bighorns have not vanished entirely from the Tucson area, but you would be hard put to make any kind of a pile of horns from the remnant population that still survives in the Pusch Ridge area of the Catalina Mountains. Not surprisingly, Pusch Ridge is ungrazed by domestic livestock.
Elk is another climax species. Studies in several states, including Arizona, Oregon, Montana and California, have shown conclusively that elk and heavy cattle use are not compatible. In fact, if elk can move out of a heavily-grazed area they will do so. Some hunters put this knowledge to use by hunting in those areas that have received little cattle use in the months preceding the hunting season.
The original elk in Arizona was the Merriam elk, a sub-species that disappeared from Arizona about the same time as the masked bobwhite. Whether overgrazing was responsible for its demise, as was the case with the bobwhite, is impossible to determine. Considering what we know today about the impact of heavy cattle use on elk populations, it would be surprising indeed if the extreme overgrazing that occurred in the late 1800's was not an important factor, perhaps the factor, that lowered the boom on our original elk population.
Let me emphasize that the problem is not grazing as such, but overgrazing. Livestock grazing in moderation can actually benefit many species of wildlife. Studies show that grazing is seldom incompatible with wildlife until it reaches the level of overgrazing. That's the point where preferred forage plants are weakened, then killed off; where undesirable weed species replace desirable forage plants; where the ground cover needed by many species for nesting and concealment is eliminated; where cattle turn to browse after the grass is wiped out and then have to compete directly with such browsing animals as deer; and, finally, where that all important topsoil begins washing away because there are no deeply rooted grasses to hold the soil in place.
Ranchers often charge that critics of overgrazing fail to appreciate the benefits that incidentally accrue to wildlife from various range improvements made specifically for livestock. Water distribution is more frequently mentioned. There is no doubt that water sources constructed for livestock are also used by wildlife. There is also little doubt that the increase in watering paces that I've witnessed in the 27 years I've worked, hunted and fished on Arizona's public rangelands, has permitted overgrazing to spread. When dependable water holes were scarce, cattle were unable to graze (or overgraze) many areas because the distance to water was too great. I've seen no evidence that the trade-off has been a plus for wildlife. On the contrary, my observations have been that, everything else being equal, wildlife is more abundant where grazing is moderate or non-existent, regardless of availability of stock water.
The photos on these pages illustrate what happens when overgrazing is carried to extremes. It is probably understanding it by a mile to call what you see in these pictures "overgrazing." The land abuse shown here has been carried to the point where it would be more correct to dub these situations ecological disasters.
Not all rangelands are as badly degraded as those in these photos, but unfortunately they do illustrate conditions in far too many areas. In the elevations of the state below the ponderosa pine belt, it is actually difficult to find areas that are not now being overgrazed to some extent; or that have not been so badly overgrazed in the past that it is difficult to determine whether they are still in a downward trend.
Some ranchers are doing a good job of range management; several have had a very real interest in maintaining proper stocking levels to avoid overgrazing. A few even consider wildlife in their range management programs. My hat is off to them. Unfortunately, as a tour of rangelands in any part of the state will demonstrate, such ranchers constitute a minority. Unless this minority can somehow be expanded soon to include a large majority of ranchers, wildlife habitat will continue to deteriorate and wildlife populations will continue to decline.
If it doesn't stop soon, Arizona will eventually look like the bleak, barren landscapes that now characterize many part of North Africa, the Middle East and much of Asia. And it will all be due to the same innocent-sounding phenomenon that devastated these other corners of the globe--overgrazing.