Skip to Main Content
Density-dependent effects on physical condition and reproduction in North American elk: an experimental test.Author(s): Kelley M. Stewart; R. Terry Bowyer; Brian L. Dick; Bruce K. Johnson; John G. Kie
Source: Oecologia. 143: 85-93
Publication Series: Scientific Journal (JRNL)
PDF: Download Publication (1.1 MB)
DescriptionDensity dependence plays a key role in life-history characteristics and population ecology of large, herbivorous mammals. We designed a manipulative experiment to test hypotheses relating effects of density-dependent mechanisms on physical condition and fecundity of North American elk (Cervus elaphus) by creating populations at low and high density. We hypothesized that if density-dependent effects were manifested principally through intraspecific competition, body condition and fecundity of females would be lower in an area of high population density than in a low-density area. Thus, we collected data on physical condition and rates of pregnancy in each experimental population. Our manipulative experiment indicated that density-dependent feedbacks affected physical condition and reproduction of adult female elk. Age-specific pregnancy rates were lower in the high-density area, although there were no differences in pregnancy of yearlings or in age at peak reproduction between areas. Age-specific rates of pregnancy began to diverge at 2 years of age between the two populations and peaked at 6 years old. Pregnancy rates were most affected by body condition and mass, although successful reproduction the previous year also reduced pregnancy rates during the current year. Our results indicated that while holding effects of winter constant, density-dependent mechanisms had a much greater effect on physical condition and fecundity than density-independent factors (e.g., precipitation and temperature). Moreover, our results demonstrated effects of differing nutrition resulting from population density during summer on body condition and reproduction. Thus, summer is a critical period for accumulation of body stores to buffer animals against winter; more emphasis should be placed on the role of spring and summer nutrition on population regulation in large, northern herbivores.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationStewart, Kelley M.; Bowyer, R. Terry; Dick, Brian L.; Johnson, Bruce K.; Kie, John G. 2005. Density-dependent effects on physical condition and reproduction in North American elk: an experimental test. Oecologia. 143: 85-93
Keywordsbody mass, body condition, Cervus elaphus, lactation, pregnancy
- Investment in constitutive immune function by north American elk experimentally maintained at two different population densities
- Influence of age of males and nutritional condition on short- and long-term reproductive success of elk.
- Modeling elk nutrition and habitat use in Western Oregon and Washington
XML: View XML