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Show near Winslow and on the adjacent grassy plateaus, and there were great herds of antelope. 19 Since 1852, herds of cattle and sheep have replaced the antelope bands, and the grass is abundant only at higher elevations in the basin where lack of water has prevented grazing by domestic stock. 20 Even the vast, unpopulated southern desert lands which are commonly imagined as eternally unchanging would in many places hardly be recognizable to those who first discovered them. Many desert watercourses that present generations are accustomed to think of as dry washes, or as intermittent streams at most, once flowed the year round. The more luxuriant desert vegetation of those early days checked the run- off from the storms more efficiently than at present, thereby reducing the volume of flash floods and distributing the stream flow more uniformly throughout the year. Those who are familiar with the bare, dry, sandy bed of the present intermittent Santa Cruz River at Tucson, in the heart of the Arizona Desert, will find it difficult to believe that prior to 1776 water there was so abundant that travelers sometimes had to wait for 6 weeks before it was possible to get horses across its swampy expanse. During the latter part of the eighteenth century the Spanish inhabitants of southern Arizona could ford the San Pedro and other rivers only at certain places. 21 Tucson was established at the site of the swamp on the Santa Cruz River because of the abundance of wood, water, and meadowland at that time. Where now there is only powder- dry desert, the grass once reached as high as the head of a man on horseback. 22 The river bottom then was densely forested with giant mesquites that formed a wide green belt extending down the valley for many miles. The region teemed with immense numbers of quail and doves. Peccaries and other wildlife of Mexican origin were abundant and beaver were plentiful. After 1800, the valley was denuded of its mes- quite forests, and the ironwood was stripped from the hills to feed the nearby lime kilns and provide fence posts. The beaver were trapped out and their dams destroyed. With the disappearance of the vegetation, the wildlife that depended on it also 19 Nichol, 1937, p. 197; Knipe, 1944, p. 22. 20 Hanson, 1924, p. 20. 21 Thomas, 1941, p. 149. 22 Carr, 1945, p. 366. 818271° 50- 6 vanished. This history has been repeated in various degrees in the San Simon ( once lush with grassy meadows), the San Pedro, and nearly every other mesquite valley of the Southwest. Changes in the desert away from the river bottoms have been equally profound. Today we are accustomed to desert lands in which there is little or nothing between the widely spaced cacti and woody desert shrubs except rocks, gravel, or bare sand. However; before 1870, the spaces between the desert shrubs were quite generally filled with grama grasses, 23 and it was these highly nutritious grasses that maintained the herds of antelope that were common in those days. After 1870, cattle increased greatly in the desert regions and the grama grasses thinned and disappeared. The trampling hoofs stripped the thin protecting layer of decaying plant materials from the surface of the soil, which then dried up, and gradually blew away, or was washed away by unchecked flood waters, leaving the bare gravel and sand that we know as " desert pavement." When the cattle removed most of the grass, the cacti and tough, unpalatable shrubs were able to multiply and predominate as they had not before. Not only were the antelope starved out, but in some regions the character of the desert vegetation itself slowly changed. Seedlings of the giant saguaro of southern Arizona require moisture- holding duff and the protecting shade of dense, low- growing brush in order to establish themselves. Over great areas of the desert these necessary conditions were removed many years ago by the grazing of cattle and have never been restored. 24 The old saguaros that lend to the Arizona Desert much of its spectacular charm now stand on practically bare soil. They are commencing to die of old age, and with their disappearance will come a great change in the landscape and far- reaching reverberations among the desert birds and lesser wild creatures that depend upon the saguaros for their existence. The new generation to replace the dying saguaro forests is sparse or lacking. Restoration of soil, decaying plant materials, and humus would require many years even if commenced at once. A saguaro seedling requires 10 to 15 years to grow to a noticeable size and 20 to 30 years to reach above the 23 Dodge, 1945, p. 6; Darrow, 1944, p. 360. 24 Dodge, 1945, 59 |