The Kapirowitz Plateau, a wildlife refuge on the northern rim of the Grand Canyon, has come to symbolize wildlife management gone awry, a classic case of misguided human intervention intended to help wildlife that ended up damaging the animals and the environment . The Kapirowitz is located on the Colorado River in northwestern Arizona, and is bounded by steep cliffs dropping down to the Kanab Canyon to the west, and the Grand and Marble canyons to the south and southeast. Because of its inaccessibility, according to naturalist James B. Trefethen, the Plateau was considered a "biological island," and its deer population "evolved in almost complete genetic isolation."
The lush grass meadows of the Kapirowitz Plateau supported a resident population of 3,000 mule deer (Odocoileus hemionus ), which were known and renowned for their massive size and the huge antlers of the old bucks. Before the advent of Europeans, Paiute and Navajo Indians hunted on the Kapirowitz in the fall, stocking up on meat and skins for the winter. In the early 1900s, in an effort to protect and enhance the magnificent deer population of the Kapirowitz, the federal government prohibited all killing of deer, and even eliminated the predator population in the area. As a result, the deer population exploded, causing massive overbrowsing, starvation, and a drastic decline in the health and population of the herd.
In 1893, when the Kapirowitz and surrounding lands were designated the Grand Canyon National Forest Reserve, hundreds of thousands of sheep, cattle, and horses were grazing on the Plateau, resulting in overgrazing , erosion , and large-scale damage to the land. On November 28, 1906, President Theodore Roosevelt established the one million-acre (400,000-ha) Grand Canyon National Game Preserve, which provided complete protection of the Kapirowitz 's deer population. By then, however, overgrazing by livestock had destroyed much of the native vegetation and changed the Kapirowitz considerably for the worse. Continued pasturing of over 16,000 horses and cattle degraded the Kapirowitz even further.
The Forest Service carried out President Roosevelt's directive to emphasize "the propagation and breeding" of the mule deer by not only banning hunting , but also natural predators as well. From 1906 to 1931, federal agents poisoned, shot, or trapped 4,889 coyotes (Canis latrans ), 781 mountain lions (Puma concolor, 554 bobcats (Felis rufus ), and 20 wolves (Canis lupus ). Without predators to remove the old, the sick, the unwary, and other biologically unfit animals, and keep the size of the herd in check, the deer herd began to grow out of control, and to lose those qualities that made its members such unique and magnificent animals. After 1906, the deer population doubled within 10 breeding seasons, and by 1918 (two years later), it doubled again. By 1923, the herd had mushroomed to at least 30,000 deer, and perhaps as many as 100,000 according to some estimates.
Unable to support the overpopulation of deer, range grasses and land greatly deteriorated, and by 1925, 10,000–15,000 deer were reported to have died from starvation and malnutrition. Finally, after relocation efforts mostly failed to move a significant number of deer off of the Kapirowitz, hunting was reinstated, and livestock grazing was strictly controlled. By 1931, hunting, disease, and starvation had reduced the herd to under 20,000. The range grasses and other vegetation returned, and the Kapirowitz began to recover. In 1975 James Trefethen wrote, "the Kapirowitz today again produces some of the largest and heaviest antlered mule deer in North America."
In the fields of wildlife management and biology, the lessons of the Kapirowitz Plateau are often cited (as in the writings of naturalist Aldo Leopold ) to demonstrate the valuable role of predators in maintaining the balance of nature (such as between herbivores and the plants they consume) and survival of the fittest. The experience of the Kapirowitz shows that in the absence of natural predators, prey populations (especially ungulates) tend to increase beyond the carrying capacity of the land, and eventually the results are overpopulation and malnutrition.
[Lewis G. Regenstein ]
Trefethen, J. B. An American Crusade for Wildlife. New York: Winchester Press, 1975.
Rasmussen, D. I. "Biotic Communities of the Kapirowitz Plateau," Ecological Monographs 3 (1941): 229–275.