Table 1. Average yield (mg) of plants per pot this study appear to warrant continued method is based on microscopic counts of grown on under, between, and garden soils. study into the effects of fertilizer on cutinized epidermal fragments and ligni- Weights are for the aboveground portions of saltbush establishment. Field studies in fied cell walls remaining after digestion the plants only. which different rates and types of fertil- (Ward, 1969; Free et al., 1970; Stewart izer are applied should provide more Soil’ and Stewart, 1970; Hansen, 1972). If the conclusive evidence as to the practicality quantification method of Sparks and Treatment Between Under Garden of facilitating large scale saltbush estab- Malechek (1967) is used, the percentage lishment with fertilization. Fertilized 174.8 a 149.3 a 135.2 a of relative density of plant fragments Unfertilized 72.5 b 85.8 b 138.6 a discerned in the dung of herbivores is Literature Cited considered to be similar to the percentage ‘Yield values followed by the same letter in any column or row were not significantly Anderson, B. L. 1972. Growth response and of dry weights for the ingested plants. different (P = 0.05). Significance was deter- deer utilization of fertilized browse. MS Even if the discernibility of plant frag- mined using the student t test. Thesis, New Mexico State University. ments is changed by digestion, the magni- Cable, D. R. 1972. Fourwing saltbush revegeta- tude is not generally great enough to tion trials in southern Arizona. J. Range destroy the identifying characteristics. Manage. 25: 150-153. unfertilized soils, whereas the garden soil Cook, C. W., L. A. Stoddart, and L. E. Harris. In spite of several centuries of live- was unaffected by fertilizer application. 1959. The chemical content in various stock grazing in desert shrub ranges in the The garden soil was reported to have been portions of the current growth of saltdesert southwest, there is little specific knowl- heavily fertilized in the past and was, shrubs and grasses during winter. Ecology edge of the quantities of plants eaten or therefore, not expected to respond to 40:644-651. shared among ungulates living together. small additions of fertilizer. Small addi- Judd, B. 1. 1962. Principal forage plants of We wish to appraise the diets of large tions of fertilizer to the between and southwestern ranges. Rocky Mountain ungulates on undisturbed open range at under soils resulted in yields that were Forest and Range Exp. Sta., Forest Serv., the eastern edge of the Mojave Desert just U.S. Dep. Agr., USDA Forest Service Paper not significantly different from the yields inside the Grand Wash Cliffs of the Grand RM-69. obtained on the heavily fertilized garden Springfield, H. W. 1970. Germination and Canyon. soil. Crusting observed in the clay loam establishment of fourwing saltbush in the The modern dung samples for compar- garden soil (but not in the between or Southwest. Rocky Mountain Forest and ison with those of extinct ground sloths under soils) may have affected the yield Range Exp. Sta., Forest Serv., U. S. Dep. (Nothrotherium shastense) and moun- of saltbush in these pots. Agr., USDA Forest Service Research Paper tain goats (Oreamnos harringtoni) were There was no difference in yield be- RM-55. collected near Rampart and Muav Caves. tween the unfertilized between and under Van Dersal, W. R. 1938. Native woody plants A qualitative appraisal of ancient dry soils, indicating that any mycorrhizal of the United States, their erosion control dung of the Shasta ground sloth from the and wildlife values. U. S. Dep. Agr. Misc. effect on nutrient availability in the caves revealed abundant fragments of Pub. 303.362 p. under soil was negligible. The additions of Williams, S. E. 1971. Microbial interaction with desert shrubs, especially Ephedra, Sphae- fertilizer had a much more pronounced fourwing saltbush. MS Thesis, New Mexico raZcea, and A triplex (Laudermilk and effect on yield on either the between or State University. Munz, 1937). under soil than did the mycorrhiza found We are sincerely grateful to Sarah R. to be present in the under soil. Woodmansee for her expertise in the Yields from the fertilized between and microscopic analyses of these samples. under treatments were pooled and were Ungulate Diets found to be significantly (P = 0.001) Procedures and Methods different from the pooled yields for in the Lower Four composite samples of dung were unfertilized and treat- between under obtained in the Lake Mead National ments. Yields due to fertilizer were about Grand Canyon Recreation Area in late March, 1972. 100% greater than yields for unfertilized Cow dung appearing to be “fresh” to pots indicating the potential for increas- R. M. HANSEN AND P. S. MARTIN several years old was collected on the ing saltbush growth and hence the proba- south side of the Colorado River between bility of establishment with the use of Highlight: Plant fragments were identified Rampart Cave and Columbine Falls. fertilizer. and quantified by a microscopic examination About 3 grams from each of about 40 of the dung of the burro, cattle, and bighorn in different locations were combined in a Conclusions the western end of the Grand Canyon, Arizona. composite sample of about 140 grams. Genera of plants common to the diets of all The experiments described herein were three ungulates were: Sphaeralcea, Bromus, Cattle were not seen in the area. conducted in the greenhouse under favor- Tridens, Muhlenbergia, Acacia, Ephedra, Bighorn sheep pellets were obtained able moisture and temperature condi- Opuntia and Tidestromia. Wherever free rang- from beneath an overhang of Muav lime- tions, and hence probably maximized the ing large herbivores occur, as in the Lake Mead stone within 1 km of Rampart Cave. Most fertilizer effect. Anderson (1972), for National Recreation Area, it is possible to study pellets were light brown and very few example, observed no significant response their diets by analysis of their dung. The diet of appeared to be recent droppings. modern large herbivores can be compared with in mean leader growth of saltbush to the On the north side of the Colorado the unique Pleistocene record of ground sloth River, opposite Muav Cave, burro dung application of 252.5 kg N/ha in the field. and extinct mountain goat dung preserved for Variation within treatments was large, over 11,000 years in adjacent caves. occurs abundantly on the exposed flats of however, and effective moisture was only an earlier delta of Lake Mead. About 12 55% of normal during the year of Ander- Many innovative methods of determin- grams of fresh burro dung (March diet) son’s work, which would probably reduce ing diets in wild and domestic herbivores were collected from four locations where any fertilizer effect. No phosphorus or have been used in recent years. One such recent deposits had been made. Burros potassium was applied with the urea used were seen or heard daily. Burro dung in Anderson’s study and only leader Authors are professors, Department of believed to represent various seasons and Range Science, Colorado State University, Fort perhaps greater than 1 year in age was growth was measured rather than total Collins, and Department of Geosciences, Uni- plant weights. versity of Arizona, Tucson. obtained from 50 random locations The large yield increases observed in Manuscript received October 7, 1972. (annual diet). About 1 gram was collected

380 JOURNAL OF : F3ANGE MANAGEMENT 26(5), September 1973 at each location. High temperatures and Table 1. Percent relative density of plant fragments discerned in burro, cattle, and bighorn dung infrequent precipitation in the area insure from near Lake Mead, Grand Canyon, Arizona, 1972. long preservation of organic litter on the soil surface. Cattle Burro Burro Bighorn March diet annual diet Twenty microscope slides were made Names of plants annual diet annual diet from each of the four composite samples 7Wens sp. 26.8 13.8 4.9 10.5 for each species of animal according to Ephedra nevadensis 15.3 0.1 0.2 9.4 the technique of Sparks and Malechek Muhlenbergia porteri 15.0 24.9 15.3 11.9 ( 1967). Twenty systematic random Sphaeralcea sp. 5.1 4.1 3.1 52.2 microscope fields were examined for each Bromus rubens 3.4 7.3 43.8 1.1 microscope slide preparation. When a Tidestromia oblongifolia 0.1 1.1 0.1 2.6 7.6 0.8 fragment was discerned that matched Phragmites communis 0.1 Acacia constricta 21.1 4.1 3.0 similar-appearing plant fragments of refer- Hilaria rigida 2.5 0.1 ence slides of identified plant species, the Opuntia sp. 0.6 4.7 0.1 fragment in the dung was then assumed Prosopis julifrora 5.4 0.1 to be from the species of reference plant. Seed 0.1 0.1 Relative percent density of discerned Stipa speciosa 1.5 0.3 plant fragments was calculated as Agave palmeri 0.6 0.4 described by Sparks and Malechek Krameria parvifolia 1.5 0.5 (1967). Analyses were based on compari- Yucca newberryi Astragalus-Oxytropis 0.1 sons with 105 species of vascular plants Lichen 0.1 from the vicinity of Rampart Cave. These Aristida wrigh tii 14.7 4.1 7.2 represent all the dominant plants and Tamarisk pentandra 9.1 3.3 “likely” forage species and most of the Forb (Nolina ?) 4.7 1.6 more uncommon plants found by Martin Peucephyllum schottii 0.1 0.9 during five trips to the cave at all seasons. Eriogonum sp. 2.7 1.2 Phoradendron californicum 0.2 0.1 Results and Observations Artemisia sp. 0.4 Carex sp. 0.2 The four most important plants in the Lycium sp. 0.1 annual diets of cattle were Tridens, Crossosoma bigelovii 0.1 A cacia, Ephedra, and Muhlen bergia , Agropyron sp. 10.7 which together made up 78% of the diet Plan tag0 insularis 5.3 (Table 1). Five plants, Muhlenbergia, Forb (Oenothera ?) 4.0 Franseria dumosa 1.8 Aristida, Tridens, Tamarisk, and Phrag- Lappula sp. 0.8 mites, made up 70% of the annual diet of Fraxinus anomala 0.6 the burro; Bromus, Muhlenbergia, and Aster biglo vii 0.1 Agropyron made up 70% of the diet in March. The most common five plants eaten by bighorns were Sphaeralcea, Muhlenbergia, Tridens, Ephedra, and pyron were in green growth stages at the Hansen, R. M. 1972. Estimating plant compo- Aristida, which made up 90% of the diet. time the sample was obtained, and as sition of wild sheep diets. First Transac- It has been reported that bighorn soon as these plants reach maturity we tions, North American Wild Sheep Confer- sheep on desert shrub ranges are often in would expect them to become of minor ence. Colorado State University, Fort Collins (1 vol.), 108-115. serious competition with the burro and importance in the diet of the burro. cattle for food plants and until the Laudermilk, .I. D., and P. A. Munz; 1938. Plants It appears that grass remains are much in the dung of from Ram- vegetation recovers in some localities, the Nothrotherium more abundant in the dung of cattle, part and Muav Caves, Arizona. Carnegie bighorn population cannot increase burro, and mountain sheep than in the Institution of Washington, No. (Russo, 1965). Cattle and bighorn diets dung of the extinct Shasta ground sloth. 487:271-281. overlap strongly for Tridens, Muhlen- As Martin et al. (1961) concluded, the Martin, P. S., B. E. Sabels, and D. Shutler, Jr. bergia, and Ephedra ; but cattle diets browsing niche occupied by the extinct 1961. Rampart Cave coprolite and ecology contain only 5% Sphaeralcea, which was Shasta ground sloth in the Pleistocene of the Shasta ground sloth. Amer. J. Sci. the principal component of the bighorns’ remains unfilled. 259: 102-127. McMichael, T. 3. 1964. Relationships between diet. Sphaeralcea is not common on the Competitiveness among ungulates for flats and slopes used by cattle, but it is desert bighorn sheep and feral burros in the plant species might be underestimated Black Mountains of Mohave County. Desert one of the most common plants on slopes when only the annual diets are compared, Bighorn Council, Trans. 8: 29-35. used only by bighorns. and the amount of competitiveness be- Russo, J. P. 1965. The desert bighorn sheep in Burros and bighorns occurred on tween given ungulate species within each Arizona. Arizona Game and Fish Depart- opposite sides of the Colorado River range type could vary. The seasonal avail- ment Wildlife Bull. No. 1, 153 p. Phoenix. where we obtained the samples; but since ability of preferred plants and the Sparks, D. R., and J. C. Malechek. 1967. most of the principal plants in both responses of plants to grazing are impor- Estimating percentage dryweight in diets. J. ungulates’ diets were eaten by both, tant factors that need to be studied Range Manage. 2 1: 203-208. intense food competition could possibly before the magnitude of ungulate comp- Stewart, D. R. M., and J. Stewart. 1970. Food develop wherever they were forced to live preference date by fecal analysis for Africa1 etition for forage plants can be plains ungulates. Zoologica Africana together. McMichael ( 1964) reported 50% understood. to 58% of the plants in the diets of burros 5:115-129. Literature Cited Ward, A. L. 1970. Stomach content and fecal and bighorns are shared. Free, J. C., R. M. Hansen, and P. L. Sims. 1970. analysis: Methods of forage identification. The March diet of the burro reflects, Estimating the dryweights of foodplants in In Range and wildlife habitat evaluation - a in part, the availability of green, growing feces of herbivores. J. Range Manage. research symposium. U.S. Dep. Agr. Misc. plants. Bromus, Muhlenbergia, and Agro- 23:300-302. Publ. 1147: 146-158.

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