Salt-Desert Shrub Ranges Is Blue Grama (Bouteloua Gracilis)
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This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. United States Department of Agriculture Managing Forest Service Intermountain Intermountain Forest and Range Experiment Station Ogden, UT 84401 Rangelands General Technical Report INT-163 June 1984 Salt-Desert :.!~ ::~ Shrub Ranges James P. Blaisdell Ralph C. Holmgren PREFACE THE AUTHORS JAMES P. BLAISDELL has retired from the position of Managers and users of salt-desert shrub rangelands Assistant Station Director for Research at the Inter will find this publication to be a reference summary to mountain Forest and Range Experiment Station, aid in planning and decisionmaking. This is not a com Ogden, Utah. He earned a B.S. degree in range prehensive literature review, but rather a distillation of management from Utah State University in 1939, an some of the most useful information for on-the-ground M.S. degree in range management from the University management. Two manuals-Hutchings and Stewart of Idaho in 1942, and a Ph.D. degree in plant ecology (1953) and Hutchings (1954)-were based on the early from the University of Minnesota in 1956. During his years of grazing research at the USDA Forest Service's 35-year career in Forest Service research, he par Desert Experimental Range (DER). They have been ticipated in and supervised range research programs, valuable guides for managers for three decades and, mostly in the Intermountain West. although out of print, are still useful. More recent ex RALPH C. HOLMGREN has retired from the position of perience at the DER, as well as much research infor range scientist at the Intermountain Station, Provo, mation from other sources, warrants the broader Utah. He earned a B.S. degree from Brigham Young updated summary in this publication. University in botany. He served as a Forest Service Because much of the content herein derives from research scientist for 30 years, the last 20 years of work at one location in the eastern part of the Great which he specialized in studies of salt-desert shrub Basin-the DER-specific results may not all be ranges at the Desert Experimental Range. directly appl icable to other salt-desert shrub areas. Although general concepts, principles, and recommen CONTENTS Page dations can be extended to distant salt-desert shrub lands, caution and professional judgment should be Introduction ........................................................................ 1 exercised in extrapolating the particulars. The Resource ................................................................. 2 Problems ......................................................................... 3 Important Species of the Salt-Desert Shrub RESEARCH SUMMARY Ecosystem ........................................................................ 4 Shrubby Chenopods ...................................................... 4 Salt-desert shrub rangelands cover some 40 million Shrubby Composites .................................................... 6 acres (16 million ha) of the Intermountain West. Much Grasses ........................................................................... 7 of this land was misused and damaged by unsound Perennial Forbs ............................................................. 8 grazing practices in pioneer times and well into the Annuals ........................................................................... 8 20th century. Plant Communities ........................................................... 9 Although productivity of the desert is low, the high Climate .............................................................................. 10 quality of the range forage produced and the vastness Weather-Plant Growth Relations .............................. 11 of the area make the desert an important part of the Soil Moisture Accumulation and Depletion ............ 11 regional resource base. Its principal value is in the an Weather and Animals ................................................. 12 nual harvest of feed by livestock. The ecosystem is Soil-Vegetation Relations .............................................. 13 fragile and easily disrupted by improper use, but under Range Condition and Trend .......................................... 15 good management, deterioration can be reversed, con Vegetation Changes and Effects of dition can improve, and areas still in good condition Livestock Grazing .......................................................... 17 can remain so under grazing use. Intensity of Grazing .................................................... 35 A grazing system compatible with other values of Season of Grazing ....................................................... 35 salt-desert shrub lands is one where grazing Recommended Grazing Management .......................... 37 allotments are used as winter and early spring range, System .......................................................................... 38 with each allotment grazed as several small units, Stocking Rate .............................................................. 39 each unit to be fully and properly harvested during one Animal Distribution ..................................................... 40 short period before the animals move on to the next Animal Nutrition .............................................................. 41 one. With annual rotation of season of use of units Range Pests ..................................................................... 42 and frequent years of rest from grazing on some of Insects .......................................................................... 42 them, the harvest can be taken without detriment to Rodents and Rabbits .................................................. 42 soil stability, wildlife and game can thrive in their Annual Weeds .............................................................. 43 natural habitat, and the esthetic quality of the desert's Revegetation .................................................................... 44 vast emptiness can be enjoyed. Integration of Multiple Uses and Values .................... 45 Wildlife .......................................................................... 45 Recreation .................................................................... 46 Soil Stabilization ......................................................... 46 Conclusions and Summary ............................................ 47 The Range and the Vegetation ................................. 47 Weather and Soil ......................................................... 47 Condition and Trend ................................................... 48 Wildlife and Range Pests .......................................... 48 The Principle Use: Grazing of Livestock ................. 48 References ....................................................................... 49 Managing Intermountain Shrub Ranges James P. Blaisdell Ralph C. Holmgren INTRODUCTION THE NORTH AMERICAN DESERT Deserts of North America were described by Shreve (1942) in a comprehensive review where he recognized four major deserts: Great Basin, Mojave, Sonoran, and Chihuahuan (fig. 1).He characterized their vegetation as predominantly shrubby. The Great Basin Desert is the northernmost of the four and includes all of the Great Basin physiographic province (Fenneman 1931) as well as adjacent parts of the Columbia and Colorado Plateaus. It extends into the Harney Basin of Oregon, the Snake River Plains of Idaho, the Red Desert of southwestern Wyoming, the western border of Colorado, northwestern New Mexico, and northern Arizona The Great Basin Desert is largely above 4,000 ft (1 200 m), summers are warm and winters are cold, and annual precipitation is mostly between 4 and 10 inches (10 and 25 em). However, the absence of a protracted dry season and the presence of moderate temperatures that result from higher latitudes and altitudes provide more favorable moisture conditions than the low-precipitation indicates. The two major plant communities of the Great Basin Desert are sagebrush-grass and salt-desert shrub, which are dominated by Artemisia tridentata and Atriplex con- fertifolia, respectively. Sagebrush-grass vegetation, which occupies some 100 million acres (40 million ha) of western rangeland, has been treated recently in a com- panion publication (Blaisdell and others 1982) and will not be considered further herein. Although estimates of the area dominated by salt-desert shrub vegetation vary 'l. considerably (Branson and others 1967; Hutchings and Figure 1.-Deserts of North America (after Stewart 1953), 40 million acres (16 million ha) is a Shreve 1942). reasonable figure for this important range ecosystem (Holmgren and Hutchings 1972). General location of this vegetation type is shown in figure 2. and the Big Horn Basin and Red Desert of Wyoming are Salt-desert shrub vegetation occurs mostly in two examples. Soils derived from these formations are so kinds of situations that promote soil salinity, alkalinity, salty and fine textured that they create salt-desert shrub or both. These are either at the bottom of drainages in habitat in a climate that would normally produce enclosed basins (bolsons) or where marine shales outcrop grassland. On the other hand, Billings (1949) described a (West 1982a). The bolsons of the Great Basin, where shadscale community in western Nevada as occupying salts and fine-textured fluvials or lacustrine materials not only the dry lake sediments with