Skip to main content
SpringerLink
Log in

Intrapopulation variation in gray wolf isotope (δ15N and δ13C) profiles: implications for the ecology of individuals

  • Community Ecology
  • Published:
Oecologia Aims and scope Submit manuscript

Abstract

Trophic relationships among organisms in terrestrial boreal ecosystems define ecological communities and are important in determining dynamics of energy flow and ecosystem function. We examined trophic relationships between the gray wolf (Canis lupus) and 18 mammalian species from the boreal forest of central Saskatchewan, Canada, using δ13C and δ15N stable isotope values measured in guard hair samples. Variance in isotope values for wolves and other carnivores was investigated as a proxy for variation in diet among individuals. Isosource, an isotopic source partitioning model, quantified the relative range in proportions of five most-likely prey items in the diets of wolves. The distribution of feasible contributions from each source was dominated by elk (Cervus elaphus; mean: 48%, range:11–75%), followed by white-tailed deer (Odocoileus virginianus; mean: 21%, range: 0–54%), moose (Alces alces; mean:14%, range: 0–41%), beaver (Castor canadensis; mean: 8%, range:0–25%) and snowshoe hare (Lepus americanus; mean: 8%, range: 0–24%). Despite social foraging, our results indicate highly variable diets among individuals and we discuss this in terms of individual versus group ecology of boreal wolves.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4

Similar content being viewed by others

References

  • Acton DF, Padbury GA, Stushnoff CT (1998) The eco-regions of Saskatchewan. Canadian Plains Research Centre, Saskatchewan Environment and Resources Management, Regina, Saskatchewan

  • Ambrose SH, Norr L (1993) Experimental evidence for the relationship of the carbon Isotope ratios of whole diet and dietary protein to those of bone collagen and Carbonate. In: Lambert JB, Grupe G (eds) Prehistoric human bone-archaeology At the molecular level. Springer, Berlin Heidelburg New York, pp 1–38

    Google Scholar 

  • Arseneault AA (2003) Status and Management of Wildlife in Saskatchewan, 1999–2001. Saskatchewan Environmental Fisheries and Wildlife Technical Report

  • Barnett, BA (1994) Carbon and nitrogen isotope ratios of caribou tissues, vascular plants and lichens from northern Alaska. MS Thesis, University of Alaska

  • Bearhop S, Adams CE, Waldron S, Fuller RA, Macleod H (2004) Determining trophic niche width: a novel approach using stable isotope analysis. J Anim Ecol 73:1007–1012

    Article  Google Scholar 

  • Beier P (1988) Reanalysis of data on sex differences in white-tailed deer diets. J Mammal 69:435

    Article  Google Scholar 

  • Ben-David M, Flynn RW, Schell DM (1997a) Annual and seasonal changes in diets of martens: evidence from stable isotope analysis. Oecologia 111:280–291

    Article  Google Scholar 

  • Ben-David M, Hanley TA, Schell DM (1997b) Seasonal changes in diets of coastal and riverine mink: the role of spawning pacific salmon. Can J Zool 75:803–811

    Article  Google Scholar 

  • Bocherens H, Drucker D (2003) Trophic level isotopic enrichment of carbon and Nitrogen in bone collagen: case studies from recent and ancient terrestrial Ecosystems. Int J Osteoarchaeol 13:46–53

    Article  Google Scholar 

  • Bolnick DI, Svanback R, Fordyce JA, Yang LH, Davis JM, Hulsey CD, Forister ML (2003) The ecology of individuals: incidence and implications of individual specialization. Am Nat 161:1–28

    Article  PubMed  Google Scholar 

  • Cabana G, Rasmussen JB (1996) Comparison of aquatic food chains using nitrogen Isotopes. Proc Natl Acad Sci USA 93:10844–10847

    Article  PubMed  CAS  Google Scholar 

  • Carbyn LN (1983) Wolf predation on elk in Riding Mountain National Park, Manitoba. J Wildl Manage 47:963–976

    Article  Google Scholar 

  • Carbyn LN, Kingsley MC (1979) Summer food habits of wolves with the emphasis on moose in Riding Mountain National Park. Proc N Am Moose Conf Workshop 15:349–361

    Google Scholar 

  • Casaux R, Favero M, Silva P, Baroni A(2001) Sex differences in diving depth and diet of Antarctic shags at the South Shetland Islands. J Field Ornithol 72:22–29

    Google Scholar 

  • Chisholm BS, Nelson DE and Schwarcz HP (1982) Stable carbon ratios as a measure of Marine versus terrestrial protein in ancient diet. Science (DC) 216:1131–1132

    Article  CAS  Google Scholar 

  • Ciucci P, Boitani L, Pelliccioni ER, Rocco M, Guy I (1996) A comparison of scat-analysis methods to assess the diet of the wolf Canis lupus. Wildl Biol 2:37–48

    Google Scholar 

  • Cormie AB, Schwarcz HP (1994) Stable isotopes of nitrogen and carbon of North American white-tailed deer and implications for paleodietary and other food web studies. Paleogeo Paleoclim Paleoecol 107:227–241

    Article  Google Scholar 

  • Creel S (1997) Cooperative hunting and group size: assumptions and currencies. Anim Behav 54:1319–1324

    Article  PubMed  Google Scholar 

  • Creel S, Creel NM (1995) Communal hunting and pack size in African wild dogs, Lycaon pictus. Anim Behav 50:1325–1339

    Article  Google Scholar 

  • Darimont CT, Reimchen TE (2002) Intra-hair stable isotope analysis implies seasonal shift to salmon in Gray wolf diet. Can J Zool 80:1638–1642

    Article  Google Scholar 

  • Darimont CT, Price MHH, Winchester NN, Gordon-Walker J, Paquet PC (2004) Predators in natural fragments: foraging ecology of wolves in British Columbia’s central and north coast archipelago. J Biogeogr 31:1–11

    Article  Google Scholar 

  • DeAngelis DL, Gross LJ (1992) Individual based models and approaches in ecology. Chapman and Hall, New York

    Google Scholar 

  • DeNiro MJ, Epstein S (1978) Influence of diet on the distribution of carbon isotopes in animals. Geochim Cosmochim Acta 42:495–506

    Article  CAS  Google Scholar 

  • DeNiro MJ, Epstein S (1981) Influence of diet on the distribution of nitrogen Isotopes in animals. Geochim Cosmochim Acta 45:341–351

    Article  CAS  Google Scholar 

  • Drucker D, Bocherens H, Pike-Tay A, Mariotti A (2001) Isotopic tracking of seasonal dietary change in dentine collagen: preliminary data from modern caribou. Earth Planet Sci 333:303–309

    Google Scholar 

  • Drucker D, Bocherens H, Billiou D (2003) Evidence for shifting environmental conditions in Southwestern France from 33,000–15,000 years ago derived from carbon-13 and nitrogen-15 natural abundances in collagen of large herbivores. Earth Planet Sci Lett 216:163–173

    Article  CAS  Google Scholar 

  • Durell, SEA Le V dit SEA (2000) Individual feeding specialization in shorebirds: population consequences and conservation implications. Biol Rev Camb Phil Soc 75:503–518

    Article  Google Scholar 

  • France RL, Peters RH (1997) Ecosystem differences in the trophic enrichment of 13C in aquatic food webs. Can J Fish Aquat Sci 54:1255–1258

    Article  Google Scholar 

  • Hall SJ, Raffaelli DG (1997) Food-web patterns: what do we really know? In: Gange AC, Brown VK (eds) Multitrophic interactions in terrestrial systems. Blackwell, Oxford, pp 395–421

    Google Scholar 

  • Hilderbrand GV, Farley SD, Robbins CT, Hanley TA, Titus K, Servheen C (1996) Use of stable isotopes to determine diets of living and extinct bears. Can J Zool 74:2080–2088

    Article  Google Scholar 

  • Hobson KA (1995) Reconstructing avian diets using stable-carbon and nitrogen isotope analysis of egg components: patterns of isotopic fractionation and turnover. Condor 97:752–762

    Article  Google Scholar 

  • Hobson KA (1999) Stable-carbon and nitrogen isotope ratios of songbird feathers grown in two terrestrial biomes: implications for evaluating trophic relationships and breeding origins. Condor 101:799–805

    Article  Google Scholar 

  • Hobson KA, Clark RG (1993) Turnover of 13C in cellular and plasma fractions of blood: implications for non-destructive sampling in avian dietary studies. Auk 110:638–641

    Google Scholar 

  • Hobson KA, Sealy SG (1991) Marine protein contributions to the diets of Northern Saw-whet Owls on the Queen Charlotte Islands, British Columbia: a stable isotope approach. Auk 108:437–440

    Google Scholar 

  • Hobson KA, Stirling I (1997) Low variation in blood δ13C among Hudson Bay polar bears: implications for metabolism and tracing terrestrial foraging. Mar Mammal Sci 13:359–367

    Article  Google Scholar 

  • Hobson KA, Alisauskas RT, Clark RG (1993) Stable-nitrogen isotope enrichment in avian tissue due to fasting and nutritional stress: implications for isotopic analyses of diet. Condor 95:388–394

    Article  Google Scholar 

  • Hobson KA, Piatt JF, Pitocchelli J (1994) Using stable isotopes to determine seabird trophic relationships. J Anim Ecol 63:786–798

    Article  Google Scholar 

  • Hobson KA, McLellan BN, Woods JG (2000) Using stable carbon and nitrogen isotopes to infer trophic relationships among black and grizzly bears in the upper Columbia River basin, British Columbia. Can J Zool 78:1332–1339

    Article  Google Scholar 

  • Horesji BL, Hornbeck GE, Raine RM (1984) Wolves, Canis lupus, kill a female black bear, Ursus americanus, in Alberta. Can Field Nat 98:368–369

    Google Scholar 

  • Jacoby ME, Hilderbrand GV, Servheen C, Schwartz CC, Arthur SM (1999) Trophic relationships of brown and black bears in several western North American ecosystems. J Wildl Manage 63:921–929

    Article  Google Scholar 

  • Kelly JF (2000) Stable isotopes of carbon and nitrogen in the study of avian and mammalian trophic ecology. Can J Zool 78:1–27

    Article  Google Scholar 

  • Krueger HW, Sullivan CH (1984) Models for carbon isotope fractionation between diet and bone. In: Turnland JR, Johonson PE (eds) Stable isotopes in nutrition ACS symposium series, vol. 258. American Chemical Society, Washington DC, pp 205–220

  • Lehman N, Clarkson P, Mech LD, Meier TJ, Wayne RK (1992) A study of the genetic relationships within and among wolf packs using DNA fingerprinting and mitochondrial DNA. Behav Ecol Sociobiol 30:83–94

    Article  Google Scholar 

  • Litvaitis JA (2000) Investigating food habits of terrestrial vertebrates. In: Boitani L, Fuller TK (eds) Research techniques in animal ecology: controversies and consequences. Columbia University Press, New York, pp 165–190

    Google Scholar 

  • Mech LD (1970) The wolf: the ecology and behaviour of an endangered species. Doubleday/Natural History, Garden City

    Google Scholar 

  • Mech LD, Boitani L (2003) Wolf social ecology. In: Mech LD, Boitani L (eds) Wolves: behavior, ecology, and conservation. University of Chicago Press, Chicago, pp 317–343

    Google Scholar 

  • Meier TJ, Burch JW, Mech LD, Adams LG (1995) Pack structure and genetic relatedness among wolf populations in a naturally-regulated population. In: Carbyn LN, Fritts SH, Seip DR (eds) Ecology and Conservation of Wolves in a Changing World. Canadian Circumpolar Institute, Edmonton, pp 393–302

    Google Scholar 

  • Meleshko DW (1986) Feeding habits of sympatric canids in an area of moderate ungulate density. PhD Thesis, University of Alberta

  • Messier F (1994) Ungulate population models with predation: a case study with the North American Moose. Ecology 75:478–488

    Article  Google Scholar 

  • Nowak RM (1999) Walker’s mammals of the world, vol I. Johns Hopkins University Press, Baltimore

  • Ostrom NE, Hedin LO, Von Fisher JC, Roberston GP (2002) Nitrogen transformation and NO3- removal at soil-stream interface: a stable isotope approach. Ecol Appl 12:1027–1043

    Google Scholar 

  • Paquet PC (1992) Prey use strategies of sympatric wolves and coyotes in Riding Mountain National Park, Manitoba. J Mammal 73:337–343

    Article  Google Scholar 

  • Paquet PC, Carbyn LN (1986) Wolves, Canis lupus, killing denning black bears, Ursus americanus, in the Riding Mountain National Park area. Can Field Nat 100:371–372

    Google Scholar 

  • Peterson BJ, Fry B (1987) Stable isotopes in ecosystem studies. Ann Rev of Ecol and Syst 18:293–320

    Article  Google Scholar 

  • Phillips DL (2001) Mixing models in analyses of diet using multiple stable isotopes: a critique. Oecologia 127:166–170

    Article  Google Scholar 

  • Phillips DL, Gregg JW (2003) Source partitioning using stable isotopes: coping with too many sources. Oecologia 136:261–269

    Article  PubMed  Google Scholar 

  • Phillips DL, Koch PL (2002) Incorporating concentration dependence in stable isotope mixing models. Oecologia 130:114–125

    Google Scholar 

  • Post DM (2002) Using stable isotopes to estimate trophic position: models, methods and assumptions. Ecology 83:703–718

    Article  Google Scholar 

  • Riga A, Van Praag HJ, Brigode N (1971) Rapport isotopique natural de l’azote dans quelques sols forestiers et agricoles de Belgique sournuis a divers vraitemments aulturneaux. Geoderma 6:213–222

    Article  CAS  Google Scholar 

  • Rogers LL, Mech LD (1981) Interactions of wolves and black bears in northeastern Minnesota. J Mammal 62:434–436

    Article  Google Scholar 

  • Roth JD, Hobson KA (2000) Stable carbon and nitrogen isotopic fractionation between diet and tissue of captive red fox: implications for dietary reconstruction. Can J Zool 78:848–852

    Article  Google Scholar 

  • Schell DM, Ziemann PJ (1989) Natural carbon isotope tracers in Arctic aquatic food webs. In: Rundel PW, Ehrlinger JR, Nagy KA (eds) Stable Isotopes in Ecological Research. Springer, Berline Heidelberg New York, pp 231–251

    Google Scholar 

  • Schwarcz HP (1991) Some theoretical aspects of isotope paleodiet studies. J Archol Sci 18:261–275

    Article  Google Scholar 

  • Scott BMV, Shackleton DM (1980) Food habits of two Vancouver Island wolf packs: a preliminary study. Can J Zool 58:1203–1207

    Article  PubMed  CAS  Google Scholar 

  • Sponheimer M, Robinson T, Ayliffe L, Roeder B, Hammer J, Passey B, West A, Cerling T, Dearing D, Ehleringer J (2003) Nitrogen isotopes in mammalian herbivores: Hair δ15N values from a controlled feeding study. Int J Osteoarchael 13:80–87

    Article  Google Scholar 

  • Szepanski MM, Ben-David M, Van Ballenberghe V (1999) Assessment of anadromous salmon resources in the diet of the Alexander Archipelago wolf using stable isotope analysis. Oecologia 120:327–335

    Article  Google Scholar 

  • Terborgh J, Estes J, Paquet PC, Ralls K, Boyd-Heger D, Miller B, Noss R (1999) The role of top carnivores in regulating terrestrial ecosystems. Wild Earth 9:42–56

    Google Scholar 

  • Tieszen LL, Boutton JW (1988) Stable carbon isotopes in terrestrial ecosystem research. In: Rundel PW, Ehleringer JR, Nagy KA (eds) Stable isotopes in ecological research. Springer, Berlin Heidelberg New York, pp 167–195

    Google Scholar 

  • Tieszen LL, Fagre T (1993) Effects of diet quality and composition on the isotopic composition of respiratory CO2, bone collagen, bioapatite, and soft tissues. In: Lambert JB, Grupe G (eds) Prehistoric human bone-archaeology at the molecular level. Springer, Berlin Heidelburg New York, pp 127–156

    Google Scholar 

  • Tieszen LL, Boutton JW, Tesdahl KG, Slade NA (1983) Fractionation and turnover of stable carbon isotopes in animal tissues: implications for δ13C analysis of diet. Oecologia 57:32–37

    Article  Google Scholar 

  • Urton EJM (2004) Population genetics, foraging ecology, and trophic relationships of grey wolves in central Saskatchewan. MSc Thesis, University of Sskatchewan

  • Weaver JL (1993) Refining the equation for interpreting prey occurrence in gray wolf scats. J Wildl Manage 57:534–538

    Article  Google Scholar 

  • Wilmers CC, Crabtree RL, Smith DW, Murphy KM, Getz WM (2003) Trophic Facilitation by introduced top predators: grey wolf subsidies to scavengers in Yellowstone National Park. J Anim Ecol 72:909–916

    Article  Google Scholar 

  • Wilson DE, Ruff S (1999) The Smithsonian book of North American mammals. Smithsonian Institution, Washington

    Google Scholar 

  • Zar JH (1999) Biostatistical analysis, 4th edn. Prentice Hall, Upper Saddle River

    Google Scholar 

Download references

Acknowledgements

Many central Saskatchewan fur trappers generously contributed hide samples; special thanks to Henri Giroux, Kelly Barlow and Ken McDaid. We thank Patricia Healy for preparing stable isotope samples. Stable isotope measurements were made at the National Water Research Institute in Saskatoon and the Department of Soil Science, University of Saskatchewan. We also thank C.T. Darimont, R. Feranec, Y.T. Hwang, and an anonymous reviewer for helpful comments on earlier versions of this manuscript. Logistical and financial support was provided by the Canadian Wildlife Service, Parks Canada, University of Saskatchewan, Mountain Equipment Co-op Environment Fund, Saskatchewan Environment, Nature Saskatchewan, Canadian Wildlife Foundation, and Saskatchewan Wildlife Federation.

Author information

Authors and Affiliations

  1. Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada

    Erin J. M. Urton & Keith A. Hobson

  2. Canadian Wildlife Service, 115 Perimeter Road, Saskatoon, SK, S7N 0X4, Canada

    Keith A. Hobson

Authors
  1. Erin J. M. Urton
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Keith A. Hobson
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Erin J. M. Urton.

Additional information

Communicated by Jim Ehleringer

Rights and permissions

Reprints and permissions

About this article

Cite this article

Urton, E.J.M., Hobson, K.A. Intrapopulation variation in gray wolf isotope (δ15N and δ13C) profiles: implications for the ecology of individuals. Oecologia 145, 316–325 (2005). https://doi.org/10.1007/s00442-005-0124-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00442-005-0124-2

Keywords

Search

Navigation