Effects of inbreeding on fitness-related traits in a small isolated moose population
Article first published online: 30 SEP 2013
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
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Ecology and Evolution
Volume 3, Issue 12, pages 4230–4242, October 2013
How to Cite
Ecology and Evolution 2013; 3(12): 4230–4242
- Issue published online: 23 OCT 2013
- Article first published online: 30 SEP 2013
- Manuscript Accepted: 29 AUG 2013
- Manuscript Revised: 26 AUG 2013
- Manuscript Received: 8 MAY 2013
- Research Council of Norway. Grant Number: FRIBIO 196304/V40
- European Research Council. Grant Number: ERC-2010-AdG 268562
- Alces alces ;
- body mass;
- genetic variation;
- inbreeding coefficients;
- inbreeding depression;
- life history traits;
- timing of birth;
- twinning rate
Inbreeding can affect fitness-related traits at different life history stages and may interact with environmental variation to induce even larger effects. We used genetic parentage assignment based on 22 microsatellite loci to determine a 25 year long pedigree for a newly established island population of moose with 20–40 reproducing individuals annually. We used the pedigree to calculate individual inbreeding coefficients and examined for effects of individual inbreeding (f) and heterozygosity on fitness-related traits. We found negative effects of f on birth date, calf body mass and twinning rate. The relationship between f and calf body mass and twinning rate were found to be separate but weaker after accounting for birth date. We found no support for an inbreeding effect on the age-specific lifetime reproductive success of females. The influence of f on birth date was related to climatic conditions during the spring prior to birth, indicating that calves with a low f were born earlier after a cold spring than calves with high f. In years with a warm spring, calf f did not affect birth date. The results suggest that severe inbreeding in moose has both indirect effects on fitness through delayed birth and lower juvenile body mass, as well as separate direct effects, as there still was a significant relationship between f and twinning rate after accounting for birth date and body mass as calf. Consequently, severe inbreeding as found in the study population may have consequences for population growth and extinction risk.