OCR Text |
Show of the terrain on foot, which occasionally led to misidentification of distant vegetation belts. By far the commonest source of error in the provisional map arose from assigning, on the basis of topographic data, a higher life zone to an isolated mountain region than actually occurred there. Although special care had been taken to avoid this mistake, the warming effect of large surrounding desert regions often was even more extreme than had been anticipated. This was exemplified in the Kaiparowits Plateau, the Abajo, La Sal, Virgin, New York, Cedar, and other mountain masses. ACKNOWLEDGMENTS Important assistance has come from the many persons who have made more or less intensive biological or botanical observations in various parts of the Colorado River Basin and who have generously contributed their time and special knowledge of local conditions in checking various portions of the present life zone map, as well as the biological information presented in the text. Of these persons, special thanks are due Dr. Angus M. Woodbury, Dr. William H. Behle of the Department of Biology, and Dr. Seville Flowers of the Department of Botany, of the University of Utah; Dr. Harold S. Colton and Edwin D. McKee of the Museum of Northern Arizona; Dr. Alden H. Miller and Dr. Seth B. Benson of the Museum of Vertebrate Zoology, University of California; A. J. van Rossem, Department of Zoology, University of California; Dr. H. C. Bryant, superintendent, Grand Canyon National Park; N. H. Frost, Field Technician, Arizona Fish and Game Commission; Joseph S. Dixon, Dr. Adolph Murie, Dr. James W. Moffett, Clifford C. Presnall, and Dr. Walter P. Taylor, of the Fish and Wildlife Service; Dr. Forrest Shreve of The Desert Laboratory, Tucson; Dr. Charles T. Vorhies, Department of Entomology and Economic Zoology, and Dr. Robert A. Darrow and Dr. Walter S. Philipps, Agricultural Experiment Station, University of Arizona; Dr. E. Raymond Hall, Museum of Natural History, University of Kansas; A. E. Borell and Dr. R. M. Bond, Soil Conservation Service; Dr. Alfred M. Bailey, Colorado Museum of Natural History; Dr. W. G. McGinnies, Rocky Mountain Forest and Range Experiment Station, and A. A. Nichol, Emergency Rubber Project, U. S. Forest Service; Dr. A. O. Weese, Department of Animal Biology, University of Oklahoma; and Dr. John W. Scott, Department of Zoology, University of Wyoming. 223 |