| OCR Text |
Show A Survey of the Deer Situation in Zion Canyon, Utah By C. C. PRESNALLl The National Parks of the United States present a unique field to the student of wildlife management in that they seek to preserve primitive con ditions, with wildlife occupying its full and proper place; and at the same time endeavor to reconcile this wilderness picture with the presence of large numbers of persons who come seeking the immeasurable values to be derived from contact with the wild. The complications resulting from the intimate relationships between people and animals are far-reaching, but certain broad remedial principles have been workd out and are being gradually applied to specific problems. The following outline of a problem, the deer situation in Zion National Park, is presented as a typical example, illustrative of certain principles and applications of wildlife management as practiced in the national parks. From a wildlife standpoint Zion Canyon can best be described as a deer pasture some 8 miles long and three-fourths of a mile wide, partially fenced in by cliffs half a mile high. There are breaks in the cliffs near the upper end, which permit deer to enter from the high plateaus to the north, and the lower end is entirely open, permitting ready egress to the semi-desert areas to the south. It is poor deer range in comparisonwith areas farther north, but it is fairly typical of most of the' southwest. Although the rainfall aver ages but fifteen inches annually, much of it occurs in the summer; and there is an ample permanent water supply throughout the Canyon. The winters are mild, sometimes being entirely free from snow. The area would be con sidered fair winter cattle range were it not so rough and rocky; only about 830 acres are level river bottom; the remaining 4000 acres are steep, rocky talus slopes. An historical background of this deer range follows: In 1862 and 1863, when the first ranches were established in the Canyon, the settlers found luxuriant vegetation on the river bottoms and ample grass and browse on the slopes. During the next fifty years the level lands were intensively farmed and the slopes were severely overgrazed. Occasional floods, especially in the early 70's, helped to denude the Canyon of vegetation and topsoil. This de pletion finally caused ranching to become so unprofitable that many of the ranches were abandoned between 1910 and 191'5; and by the time the National Park Service started conservation measures in 1918, there was not much left to conserve except gravel bars and dusty trails. This also applied to the animal life, including deer, which had been persistently hunted up to 1918. Under the protection given by the Park Service, the vegetation made a quicker initial recovery than did the deer; a contributing factor being that natural barriers partially impede the influx of deer from surrounding areas. Ten years elapsed before the Canyon became stocked with deer to its full capacity, during which time the vegetation made a good recovery, reaching perhaps 75 percent of its original density. In this ten-year period, 1918 to 1928, another factor, the human element, had been assuming a gradually increasing importance, as more and more visitors came to the park each year. Human use of the park was, and no doubt always will be, concentrated in Zion Canyon, causing profound changes in the delicate balance between deer and their natural predators. Cougars, ---.- 1 Park Naturalist, Zion National Park. Utah. 107 |
