Abstract
Much of the research into herbivore ecology and evolution has focused on patterns and mechanisms of niche partitioning in the diets of specialized grazers and browsers, but the significance of the balance of grazing and browsing within intermediate feeders present unique questions that have received less attention. We explored the nutritional effects of varying the balance of grass and browse in the winter diets of elk (Cervus elaphus). We compiled published data from three similar studies that monitored the mass dynamics of captive elk fed diets of pure grass, pure browse or 1 of 14 mixed diets in winter feeding trials. Elk lost mass (up to 22% of initial body weight) in 29 of 33 feeding trials, similar to wild elk in winter. We used regression models of mass dynamics, considering the linear, quadratic or logarithmic effects of the proportion of the diet that was grass (≈1 − proportion of the diet that was browse) and the additive and interactive effects of nitrogen intake. Diet composition had strong effects on mass dynamics, and all models explained ≥73% of the variation (adjusted r 2) in mass dynamics. Nitrogen intake had uniformly positive effects on mass balance, and increasing grass intake caused improved maintenance of body mass up to a point, but further increases in the proportion of grass in the diet had neutral or negative effects on body mass. Overall, the data suggest that elk are adapted to consuming mixed diets. Nonetheless, data on the foraging behavior and diet selection of wild elk in many populations show that elk often consume grass-dominated diets and sometimes consume browse-dominated diets, but rarely consume mixed diets. Physiological adaptations to mixed diets may place unique spatio-temporal constraints on diet selection in intermediate feeders and impose large penalties for a sub-optimal balance of grazing and browsing.
Similar content being viewed by others
References
Adams DC, Pfister JA, Short RE, Cates RG, Knapp BW, Wiedmeier RD (1992) Pine needle effects on in-vivo and in-vitro digestibility of crested wheatgrass. J Range Manage 45:249–253
Allaye-Chan AC (1991) Physiological and ecological determinants of nutrient partitioning in caribou and reindeer. PhD thesis, University of Alaska, Fairbanks
Arthun D, Holechek JL, Wallace JD, Galyean ML, Cardenas M, Rafique S (1992a) Forb and shrub influences on steer nitrogen retention. J Range Manage 45:133–136
Arthun D, Holechek JL, Wallace JD, Gaylean ML, Cardenas M (1992b) Forb and shrub effects on ruminal fermentation in cattle. J Range Manage 45:519–522
Augustine DJ, McNaughton SJ (1998) Ungulate effects on the functional species composition of plant communities: herbivore selectivity and plant tolerance. J Wildl Manage 62:1165–1183
Baker DL, Hansen DR (1985) Comparative digestion of grass in mule deer and elk. J Wildl Manage 49:77–79
Baker DL, Hobbs NT (1987) Strategies of digestion–digestive efficiency and retention time of forage diets in montane ungulates. Can J Zool 65:1978–1984
Banks PB, Hume ID, Crowe O (1999) Behavioural, morphological and dietary response of rabbits to predation risk from foxes. Oikos 85:247–256
Baty GR (1995) Resources partitioning and browse use by sympatric elk, mule deer, and white-tailed deer on a winter range in Montana. PhD Thesis. University of Montana, Missoula
Bellows S, Short RE, Ford SP (1996) Effects of feeding pine needles to late pregnant elk and goats. Proc Western Sect Soc Anim Sci 47:186–188
Belovsky GE (1981) Food plant selection by a generalist herbivore—the moose. Ecology 62:1020–1030
Blackburn HD, Kothmann MM (1991) Modeling diet selection and intake for grazing herbivores. Ecol Model 57:145–163
Board on Agriculture (2000) Energy. In: Buchanan-Smith J, Berger LL, Ferrell C, Fox DG, Galyean M, Hutcheson DP, Klopfenstein TJ, Spears J (eds) Nutrient requirements of beef cattle. National Academies Press, Washington DC, pp 3–15
Bohnert DW, Schauer CS, Bauer ML, Delcurto T (2002) Influence of rumen protein degradability and supplementation frequency on steers consuming low-quality forage: I. site of digestion and microbial efficiency. J Anim Sci 80:2967–2977
Bolnick DI (2001) Intraspecific competition favours niche width expansion in Drosophila melanogaster. Nature 410:463–466
Brown RD, Hellgren EC, Abbott M, Ruthven DC, Bingham RL (1995) Effects of dietary energy and protein restriction on nutritional indexes of female white-tailed deer. J Wildl Manage 59:595–609
Byers JA (1997) American pronghorn: social adaptations and the ghosts of predators past. University of Chicago Press, Chicago
Case RL (1994) Adaptations of northern ungulates to seasonal cycles in nitrogen intake. PhD Thesis. University of Alberta, Edmonton
Christianson DA, Creel S (2007) A review of environmental factors affecting elk winter diets. J Wildl Manage 71:164–176
Church DC, Hines WH (1978) Ruminoreticular characteristics of elk. J Wildl Manage 42:654–659
Clauss M, Lechner-Doll M, Streich WJ (2003) Ruminant diversification as an adaptation to the physicomechanical characteristics of forage. A reevaluation of an old debate and a new hypothesis. Oikos 102:253–262
Cook JG (2002) Nutrition and food. In: Toweill DE, Thomas JW (eds) North American elk: ecology and management, 1st edn. Smithsonian Institution, Washington DC, pp 259–349
Cook JG, Johnson BK, Cook RC, Riggs RA, Delcurto T, Bryant LD, Irwin LL (2004a) Effects of summer-autumn nutrition and parturition date on reproduction and survival of elk. Wildl Monogr 154:1–61
Cook RC, Cook JG, Mech LD (2004b) Nutritional condition of northern Yellowstone elk. J Mammal 85:714–722
Creel S, Winnie J, Maxwell B, Hamlin K, Creel M (2005) Elk alter habitat selection as an antipredator response to wolves. Ecology 86:3387–3397
Creel S, Christianson D, Liley S, Winnie JA (2007) Predation risk affects reproductive physiology and demography of elk. Science 315:960
Currier TA, Bohnert DW, Falck SJ, Bartle SJ (2004) Daily and alternate day supplementation of urea or biuret to ruminants consuming low-quality forage: I. Effects on cow performance and the efficiency of nitrogen use in wethers. J Anim Sci 82:1508–1517
Davies HL, Robinson TF, Roeder BL, Sharp ME, Johnston NP, Christensen AC (2007) Plasma metabolites and nitrogen balance in Lama glama associated with forage quality at altitude. Small Rumin Res 69:1–9
Dehority BA, Grings EE, Short RE (1999) Effects of cross-inoculation from elk and feeding pine needles on the protozoan fauna of pregnant cows: occurrence of Parentodinium africanum in domestic US cattle (Bos taurus). J Eukaryot Microbiol 46:632–636
Fox J (1997) Applied regression analysis, linear models, and related methods. Sage Publications Inc., Thousand Oaks
Friedel BA, Hudson RJ (1994) Productivity of farmed wapiti in Alberta. Can J Anim Sci 74:297–303
Fritz H, Loison A (2006) Large herbivores across biomes. In: Danell K, Bergstrom R, Duncan P, Pastor J (eds) Large herbivore ecology, ecosystem dynamics and conservation. Cambridge University, Cambridge, pp 19–49
Galbraith JK, Mathison GW, Hudson RJ, McAllister TA, Cheng KJ (1998) Intake, digestibility, methane and heat production in bison, wapiti and white-tailed deer. Can J Anim Sci 78:681–691
Gates JE, Gysel LW (1978) Avian nest dispersion and fledging success in field-forest ecotones. Ecology 59:871–883
Gates CC, Hudson RJ (1981) Weight dynamics of wapiti in the boreal forest. Acta Theriol (Warsz) 26:407–418
Gedir JV, Hudson RJ (2000) Seasonal foraging behavioural compensation in reproductive wapiti hinds (Cervus elaphus canadensis). Appl Anim Behav Sci 67:137–150
Geis AF (1954) The food consumption and relative digestibility of various winter diets fed to elk under controlled conditions. MS Thesis. Montana State University, Bozeman
Geist V (2002) Adaptive behavioral strategies. In: Toweill DE, Thomas JW (eds) North American elk: ecology and management, 1st edn. Smithsonian Institution, Washington DC, pp 389–433
Greer KR, Howe RE (1964) Winter weights of northern Yellowstone elk, 1961–1962. Transactions of the Twenty-ninth North American Wildlife Conference, pp 237–248
Greer KR, Kirsch JB, Yeager HW (1970) Seasonal food habits of the Northern Yellowstone elk herds during 1957 and 1962–1967 as determined from 793 rumen samples. Federal reports. Montana Fish Wildlife and Parks. Bozeman, Montana
Hansen RM, Reid LD (1975) Diet overlap of deer, elk, and cattle in southern Colorado. J Range Manage 28:43–47
Helwig LL (1957) The value of conifers as a winter feed for elk (Cervus elaphus candensis) determined under controlled conditions. MS Thesis, Montana State University, Bozeman
Hobbs NT, Baker DL, Ellis JE, Swift DM (1981) Composition and quality of elk winter diets in Colorado. J Wildl Manage 45:156–171
Hobbs NT, Baker DL, Gill RB (1983) Comparative nutritional ecology of montane ungulates during winter. J Wildl Manage 47:1–16
Hobbs NT (1979) Winter diet quality and nutritional status of elk in the upper montane zone, Colorado. PhD Thesis. Colorado State University, Fort Collins
Hofmann RR, Stewart RM (1972) Grazer or browser: a classification based on the stomach-structure and feeding habits of east African ruminants. Mammal J Morphol Biol Syst Mammiferes 36:226–240
Hudson RJ, Kozak HM, Adamczewski JZ, Olsen CD (1991) Reproductive performance of farmed wapiti (Cervus elaphus nelsoni). Small Rumin Res 4:19–28
Hudson RJ, Haigh JC, Bubenik AB (2002) Physical and physiological adaptations. In: Toweill DE, Thomas JW (eds) North American elk: ecology and management, 1st edn. Smithsonian Institution, Washington DC, pp 199–257
Hungerford CR (1952) The food consumption and weight response of elk (Cervus elaphus nelsoni) under winter conditions. MS Thesis. Montana State University, Bozeman
Illuiss AW, Gordon IJ (1990) Variation in foraging behavior in red deer and the consequences for population demography. J Anim Ecol 59:89–101
Janis CM, Damuth J, Theodor JM (2000) Miocene ungulates and terrestrial primary productivity: where have all the browsers gone? Proc Natl Acad Sci USA 97:7899–7904
Janis CM, Damuth J, Theodora JM (2002) The origins and evolution of the North American grassland biome: the story from the hoofed mammals. Palaeogeogr Palaeoclimatol Palaeoecol 177:183–198
Jarman PJ (1974) Social organization of antelope in relation to their ecology. Behaviour 48:215–267
Jenkins KJ, Wright RG (1987) Dietary niche relationships among cervids relative to winter snowpack in northwestern Montana, USA. Can J Zool 65:1397–1401
Jiang Z, Hudson R (1994) Seasonal energy requirements of wapiti (Cervus elaphus) for maintenance and growth. Can J Anim Sci 74:97–102
Kaitho RJ, Umunna NN, Nsahlai IV, Tamminga S, Van Bruchem J (1997) Utilization of browse supplements with varying tannin levels by Ethiopian Menz sheep—1. Intake, digestibility and live weight changes. Agroforestry Syst 39:145–159
Kingery JL, Mosley JC, Bordwell KC (1996) Dietary overlap among cattle and cervids in northern Idaho forests. J Range Manage 49:8–15
Krebs GL, Howard DM, Dods K (2007) The effects of feeding Acacia saligna on feed intake, nitrogen balance and rumen metabolism in sheep. Asian-Aust J Anim Sci 20:1367–1373
Kufeld RC (1973) Foods eaten by the Rocky Mountain elk. J Range Manage 26:106–113
Martin TE (2007) Climate correlates of 20 years of trophic changes in a high-elevation riparian system. Ecology 88:367–380
McCorquodale SM (1993) Winter foraging behavior of elk in the shrub-steppe of Washington. J Wildl Manage 57:881–890
Mcnamara JM, Houston AI (1987) Starvation and predation as factors limiting population size. Ecology 68:1515–1519
McNaughton SJ (1985) Ecology of a grazing ecosystem—the serengeti. Ecol Monogr 55:259–294
McNaughton SJ, Georgiadis NJ (1986) Ecology of African grazing and browsing mammals. Annu Rev Ecol Syst 17:39–65
Morgantini LE, Hudson RJ (1985) Changes in diets of wapiti during a hunting season. J Range Manage 38:77–79
Morgantini LE, Hudson RJ (1989) Nutritional significance of wapiti (Cervus elaphus) migrations to alpine ranges in western Alberta, Canada. Arc Alp Res 21:288–295
Morris MS, Schwartz JE (1957) Mule deer and elk food habits on the National Bison Range. J Wildl Manage 21:189–193
Mould ED, Robbins CT (1981) Nitrogen metabolism in elk. J Wildl Manage 45:323–334
Mould ED, Robbins CT (1982) Digestive capabilities in elk compared to white-tailed deer. J Wildl Manage 46:22–29
Newman JA, Parsons AJ, Thornley JHM, Penning PD, Krebs JR (1995) Optimal diet selection by a generalist grazing herbivore. Funct Ecol 9:255–268
Ngugi RK, Hinds FC, Powell J (1995) Mountain big sagebrush browse decreases dry-matter intake, digestibility, and nutritive quality of sheep diets. J Range Manage 48:487–492
Nunez-Hernandez G, Wallace JD, Holechek JL, Galyean ML, King DW, Kattnig RM (1991) Mountain mahogany and cottonseed meal as supplements for grass hay. J Range Manage 44:497–500
Olff H, Ritchie ME, Prins HHT (2002) Global environmental controls of diversity in large herbivores. Nature 415:901–904
Owen-Smith N, Novellie P (1982) What should a clever ungulate eat? Am Nat 119:151–178
Parker KL, Barboza PS, Stephenson TR (2005) Protein conservation in female caribou (Rangifer tarandus): effects of decreasing diet quality during winter. J Mammal 86:610–622
Perez-Barberia FJ, Gordon IJ (2001) Relationships between oral morphology and feeding style in the Ungulata: a phylogenetically controlled evaluation. Proc R Soc Lond B Biol Sci 268:1023–1032
Phiri DM, Coulman B, Steppler HA, Kamara CS, Kwesiga F (1992) The effect of browse supplementation on maize husk utilization by goats. Agroforestry Syst 17:153–158
Rafique S, Arthun DP, Galyean ML, Holechek JL, Wallace JD (1988) Effects of forb and shrub diets on ruminant nitrogen balance. I. Sheep studies. Proc West Sec Am Soc Anim Sci 39:200–203
Rafique S, Wallace JD, Holechek JL, Galyean ML, Arthun DP (1992) Influence of forbs and shrubs on nutrient digestion and balance in sheep fed grass hay. Small Rumin Res 7:113–122
Rafique S, Wallace JD, Holechek JL, Galyean ML, Arthun DP (1993) Influence of forbs and shrubs on intake, digestibility, and nitrogen and energy balance in sheep fed low-quality straw. Agroforestry Syst 24:95–104
Renecker LA, Hudson RJ (1990) Digestive kinetics of moose (Alces alces), wapiti (Cervus elaphus) and cattle. Anim Prod 50:51–61
Rowland MM, Alldredge AW, Ellis JE, Weber BJ, White GC (1983) Comparative winter diets of elk in New Mexico. J Wildl Manage 47:924–932
Schauer CS, Bohnert DW, Ganskopp DC, Richards CJ, Falck SJ (2005) Influence of protein supplementation frequency on cows consuming low-quality forage: performance, grazing behavior, and variation in supplement intake. J Anim Sci 83:1715–1725
Schlaepfer MA, Runge MC, Sherman PW (2002) Ecological and evolutionary traps. Trends Ecol Evol 17:474–480
Sih A (1982) Optimal patch use—variation in selective pressure for efficient foraging. Am Nat 120:666–685
Singer FJ, Norland JE (1994) Niche relationships within a guild of ungulate species in Yellowstone National Park, Wyoming, following release from artificial controls. Can J Zool 72:1383–1394
Singer FJ, Harting A, Symonds KK, Coughenour MB (1997) Density dependence, compensation, and environmental effects on elk calf mortality in Yellowstone National Park. J Wildl Manage 61:12–25
Stewart KM, Bowyer RT, Kie JG, Cimon NJ, Johnson BK (2002) Temporospatial distributions of elk, mule deer, and cattle: resource partitioning and competitive displacement. J Mammal 83:229–244
Stewart KM, Bowyer RT, Dick BL, Johnson BK, Kie JG (2005) Density-dependent effects on physical condition and reproduction in North American elk: an experimental test. Oecologia 143:85–93
Telfer ES (1994) Cattle and cervid interactions on a foothills watershed in southwestern Alberta. Can Field-Nat 108:186–194
Thorne ET, Dean RE, Hepworth WG (1976) Nutrition during gestation in relation to successful reproduction in elk. J Wildl Manage 40:330–335
Vales DJ, Peek JM (1996) Responses of elk to the 1988 Yellowstone fires and drought. In: Greenlee JM (ed) Second biennial conference on science in the Greater Yellowstone Ecosystem. Ecological implications of fire in Greater Yellowstone. International Association of WildlandFire, Fairfield, pp 159–167
Van Soest PJ (1982) Nutritional ecology of the ruminant. Cornell Press, Ithaca
Verheyden-Tixier H, Renaud PC, Morellet N, Besle JM, Dumont B (2008) Selection for nutrients by red deer hinds feeding on a mixed forest edge. Oecologia. doi:10.1007/s00442-008-1020-3
Wairimu S, Hudson R (1993) Foraging dynamics of wapiti stags (Cervus elaphus) during compensatory growth. Appl Anim Behav Sci 36:65–79
Ward AL (1971) In-vitro digestibility of elk winter forage in southern Wyoming. J Wildl Manage 35:681
Werner EE, Mittelbach GG, Hall DJ, Gilliam JF (1983) Experimental tests of optimal habitat use in fish—the role of relative habitat profitability. Ecology 64:1525–1539
White RG (1983) Foraging patterns and their multiplier effects on productivity of northern ungulates. Oikos 40:377–384
Wickstrom ML, Robbins CT, Hanley TA, Spalinger DE, Parish SM (1984) Food intake and foraging energetics of elk and mule deer. J Wildl Manage 48:1285–1301
Wolkers H, Wensing T, Schonewille JT, Vantklooster AT (1994) Undernutrition in relation to changed tissue composition in red deer (Cervus elaphus). Can J Zool 72:1837–1840
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Jean-Michel Gaillard.
Rights and permissions
About this article
Cite this article
Christianson, D., Creel, S. Effects of grass and browse consumption on the winter mass dynamics of elk. Oecologia 158, 603–613 (2009). https://doi.org/10.1007/s00442-008-1200-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00442-008-1200-1