A nutritionally mediated risk effect of wolves on elk

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

Though it is widely argued that antipredator responses carry nutritional costs, or risk effects, these costs are rarely measured in wild populations. To quantify risk effects in elk, a species that strongly responds to the presence of wolves, we noninvasive monitored diet selection and nutrient balance in wintering elk in the Upper Gallatin, Montana, USA, over three winters while quantifying the local presence of wolves at a fine spatiotemporal scale. Standard nutritional indices based on the botanical and chemical composition of 786 fecal samples, 606 snow urine samples, and 224 forage samples showed that elk were generally malnourished throughout winter. Increased selection for dietary nitrogen within forage types (e.g., grasses) led. to -8% higher fecal nitrogen in the presence of wolves. However, urinary allantoin : creatinine and potassium : creatinine ratios decreased in the presence of wolves, suggesting large declines in energy intake, equal to 27% of maintenance requirements. Urinary nitrogen : creatinine ratios confirmed that deficiencies in nitrogen and/or energy were exacerbated in the presence of wolves, leading to increased endogenous protein catabolism. Overall, the nutritional effects of wolf presence may be of sufficient magnitude to reduce survival and reproduction in wintering elk. Nutritionally mediated risk effects may be important for understanding predator-prey dynamics in wild populations, but such effects could be masked as bottom-up forces if antipredator responses are not considered.

Original languageEnglish (US)
Pages (from-to)1184-1191
Number of pages8
JournalEcology
Volume91
Issue number4
DOIs
StatePublished - Apr 2010
Externally publishedYes

Fingerprint

elks
wolves
creatinine
nitrogen
wild population
forage
catabolism
winter
allantoin
nutrition assessment
nutrient balance
cost
botanical composition
urine
feeding preferences
energy
protein metabolism
sampling
snow
potassium

Keywords

  • Cervus elaphus
  • Elk
  • Energy
  • Foraging behavior
  • Intake
  • Metabolism
  • Montana
  • Nitrogen
  • Predatorprey interactions
  • Risk-effects
  • Starvation
  • Upper gallatin
  • USA
  • Wolves

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

A nutritionally mediated risk effect of wolves on elk. / Christianson, David A; Creel, Scott.

In: Ecology, Vol. 91, No. 4, 04.2010, p. 1184-1191.

Research output: Contribution to journalArticle

Christianson, David A ; Creel, Scott. / A nutritionally mediated risk effect of wolves on elk. In: Ecology. 2010 ; Vol. 91, No. 4. pp. 1184-1191.
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