FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Ecology and evolution2014; 4(19); 3851-3860; doi: 10.1002/ece3.1250

Interacting effects of age, density, and weather on survival and current reproduction for a large mammal.

Abstract: Individual-based study of natural populations allows for accurate and precise estimation of fitness components and the extent to which they might vary with ecological conditions. By tracking the fates of all 701 horses known to have lived on Sable Island, Canada, from 2009 to 2013 (where there is no predation, human interference, or interspecific competition for food), we present a detailed analysis of structured population dynamics with focus on interacting effects of intraspecific competition and weather on reproduction and survival. Annual survival of adult females (0.866 ± 0.107 [[Formula: see text] ± SE]) was lower than that of 3-year-olds (0.955 ± 0.051), although annual fecundity (producing a foal in a year that was observed during our census) was higher in adults (0.616 ± 0.023) compared to 3-year-olds (0.402 ± 0.054). Milder winters and lower densities during gestation increased fecundity. Density negatively impacted survival for all age and sex categories; however, highest adult female survival was observed during high-density years coupled with a harsh winter, the result expected if pregnancy loss during winter or loss of foals in spring improved survival. Three-year-old females, which reproduced at lower rates, experienced higher survival than adults. Our results contrast with a previous study of feral horses that suggested recently feral ungulates might be artificially selected to reproduce even when costs to survival are high. In part, this may be because of the comparably long history of feralization (250 years; at least 25 generations) for Sable Island horses.
Get Full Text
Publication Date: 2014-09-18 PubMed ID: 25614799PubMed Central: PMC4301048DOI: 10.1002/ece3.1250Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study employed an individual-based tracking method on a population of 701 horses on Sable Island, Canada to evaluate the impact of ecological conditions, interspecific competition and weather on reproduction and survival. The study contradicted a prior study of feral horses’ reproduction survival relationship and found that adult female horse survival was highest in high-density years accompanied by harsh winters.

Research Methodology

  • The research employed an individual-based study on a population of 701 horses on Sable Island, Canada from 2009 to 2013. The choice of location was influenced by the absence of predation, human interference, or interspecific competition for food. This setting provided a suitable environment to study the structured population dynamics.
  • The horses were observed and their survival and current reproduction rates were recorded in the study period. Researchers analyzed survival and fecundity rates (the ability to produce offspring per year) across different age groups and under varying ecological conditions.

Key Findings

  • The annual survival of adult females (0.866 ± 0.107) was found to be lower than that of 3-year-olds (0.955 ± 0.051). This indicates a higher mortality risk for adult females within the study period.
  • Adult females, however, recorded a higher annual fecundity (0.616 ± 0.023) compared to 3-year-olds (0.402 ± 0.054), pointing out greater reproductive capacity in adults than the younger 3 year-old group.
  • A positive correlation was found between milder winters and lower population densities during gestation with increased fecundity rates. This suggests that favorable climates and less population pressure lead to an increased likelihood of producing offspring.
  • Density negatively impacted the survival for all age and sex categories. Paradoxically, the highest adult female survival was noted during high-density years coupled with harsh winters.
  • This high survival rate during harsh conditions for adult females was hypothesized to be due to pregnancy loss in winter or the loss of foals in spring, which ultimately improved survival rates of the adults.

Contradiction with Previous Studies and Possible Explanation

  • The results contradicted a previous study on feral horses which suggested that these animals might be artificially selected to reproduce even when survival costs are high. This apparent discrepancy might be ascribed to different feralization ages of the horse populations studied. The Sable Island horses had a considerably long feralization history (250 years; at least 25 generations).

Cite This Article

APA
Richard E, Simpson SE, Medill SA, McLoughlin PD. (2014). Interacting effects of age, density, and weather on survival and current reproduction for a large mammal. Ecol Evol, 4(19), 3851-3860. https://doi.org/10.1002/ece3.1250

Publication

Ecology and evolution
ISSN: 2045-7758
NlmUniqueID: 101566408
Country: England
Language: English
Volume: 4
Issue: 19
Pages: 3851-3860

Researcher Affiliations

Richard, Emmanuelle
  • Department of Biology, University of Saskatchewan 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.
Simpson, Steven E
  • Department of Biology, University of Saskatchewan 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.
Medill, Sarah A
  • Department of Biology, University of Saskatchewan 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.
McLoughlin, Philip D
  • Department of Biology, University of Saskatchewan 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.

References

This article includes 51 references
  1. Adams LG, Singer FJ, Dale BW. Caribou calf mortality in Denali National Park, Alaska.. J. Wildl. Manag. 1995;59:584–594.
  2. Albon SD, Coulson TN, Brown D, Guinness FE, Pemberton JM, Clutton-Brock TH. Temporal changes in key factors and key age groups influencing the population dynamics of female red deer.. J. Anim. Ecol. 2000;69:1099–1110.
  3. Berger J. Wild horses of the Great Basin: social competition and population size, Wildlife behavior and ecology.. Chicago, IL: Univ. of Chicago; 1986. p. 330.
  4. Brault S, Caswell H. Pod-specific demography of killer whales (Orcinus orca.. Ecology 1993;74:1444–1454.
  5. Burnham KP, Anderson DR. Model selection and multimodel inference: a practical information-theoretic approach.. New York, NY: Springer-Verlag; 2002. p. 448.
  6. Cameron RD, Smith WT, Fancy SG, Ger-hart KL, White RG. Calving success of female caribou in relation to body weight.. Can. J. Zool. 1993;71:480–486.
  7. Caswell H. Matrix population models construction, analysis, and interpretation.. Sunderland, MA: Sinauer Associates, Inc; 2001. p. 710.
  8. Christie BJ. The horses of Sable Island.. Lawrencestown, NS: Pottersfield Press; 1995. p. 111.
  9. Clutton-Brock J. Domesticated animals from early times.. Austin, TX: Univ. Texas Press; 1981.
  10. Clutton-Brock T, Sheldon BC. Individuals and populations: the role of long-term, individual-based studies of animals in ecology and evolutionary biology.. Trends Ecol Evol 2010 Oct;25(10):562-73.
    pubmed: 20828863doi: 10.1016/j.tree.2010.08.002google scholar: lookup
  11. Clutton-Brock TH, Albon SD, Guinness FE. Interactions between population density and maternal characteristics affecting fecundity and juvenile survival in red deer.. J. Anim. Ecol. 1987;56:857–7129.
  12. Contasti AL, Tissier EJ, Johnstone JF, McLoughlin PD. Explaining spatial heterogeneity in population dynamics and genetics from spatial variation in resources for a large herbivore.. PLoS One 2012;7(10):e47858.
    pmc: PMC3485331pubmed: 23118900doi: 10.1371/journal.pone.0047858google scholar: lookup
  13. Contasti AL, Van Beest FM, Vander Wal E, Mcloughlin PD. Identifying hidden sinks in growing populations from individual fates and movements: the feral horses of Sable Island.. J. Wildl. Manag. 2013;77:1545–1552.
  14. Coulson T, Catchpole EA, Albon SD, Morgan BJ, Pemberton JM, Clutton-Brock TH, Crawley MJ, Grenfell BT. Age, sex, density, winter weather, and population crashes in Soay sheep.. Science 2001 May 25;292(5521):1528-31.
    pubmed: 11375487doi: 10.1126/science.292.5521.1528google scholar: lookup
  15. Crozier LG, Zabel RW, Hockersmith EE, Achord S. Interacting effects of density and temperature on body size in multiple populations of Chinook salmon.. J Anim Ecol 2010 Mar;79(2):342-9.
    pubmed: 20002859doi: 10.1111/j.1365-2656.2009.01641.xgoogle scholar: lookup
  16. Cymbaluk NF. Cold housing effects on growth and nutrient demand of young horses.. J Anim Sci 1990 Oct;68(10):3152-62.
    pubmed: 2254193doi: 10.2527/1990.68103152xgoogle scholar: lookup
  17. Festa-Bianchet M, Jorgenson JT, Lucherini M, Wishart WD. Life-history consequences of variation in age of primiparity in bighorn ewes.. Ecology 1995;76:871–881.
  18. Festa-Bianchet M, Gaillard JM, Jorgenson JT. Mass- and density-dependent reproductive success and reproductive costs in a capital breeder.. Am Nat 1998 Sep;152(3):367-79.
    pubmed: 18811445doi: 10.1086/286175google scholar: lookup
  19. Festa-Bianchet M, Gaillard JM, Côté SD. Variable age structure and apparent density dependence in survival of adult ungulates.. J. Anim. Ecol. 2003;72:640–649.
  20. Forchhammer MC, Clutton-Brock TH, Lindström J, Albon SD. Climate and population density induce long-term cohort variation in a northern ungulate.. J. Anim. Ecol. 2001;70:721–729.
  21. Gaillard JM, Festa-Bianchet M, Yoccoz NG. Population dynamics of large herbivores: variable recruitment with constant adult survival.. Trends Ecol Evol 1998 Feb 1;13(2):58-63.
    pubmed: 21238201doi: 10.1016/s0169-5347(97)01237-8google scholar: lookup
  22. Gaillard J-M, Festa-Bianchet M, Yoccoz NG, Loison A, Toigo C. Temporal variation in fitness components and population dynamics of large herbivores.. Annu. Rev. Ecol. Evol. Syst. 2000;31:367–393.
  23. Gaillard JM, Hewison AJ, Klein F, Plard F, Douhard M, Davison R, Bonenfant C. How does climate change influence demographic processes of widespread species? Lessons from the comparative analysis of contrasted populations of roe deer.. Ecol Lett 2013 May;16 Suppl 1:48-57.
    pubmed: 23297773doi: 10.1111/ele.12059google scholar: lookup
  24. Garrott RA, Taylor L. Dynamics of a feral horse population in Montana.. J. Wildl. Manag. 1990;54:603–612.
  25. Garrott RA, Siniff DB, Eberhardt LL. Growth rates of feral horse populations.. J. Wildl. Manag. 1991;55:641–648.
  26. Garrott RA, Eberhardt LL, White PJ, Rotella J. Climate-induced variation in vital rates of an unharvested large-herbivore population.. Can. J. Zool. 2003;81:33–45.
  27. Grange S, Duncan P, Gaillard JM. Poor horse traders: large mammals trade survival for reproduction during the process of feralization.. Proc Biol Sci 2009 May 22;276(1663):1911-9.
    pmc: PMC2674491pubmed: 19324787doi: 10.1098/rspb.2008.1828google scholar: lookup
  28. Helle T, Aspi J, Lempa K, Taskinen E. Strategies to avoid biting flies by reindeer: field experiments with silhouette traps.. Ann. Zool. Fenn. 1992;29:69–74.
  29. Heppell SS, Caswell H, Crowder LB. Life histories and elasticity patterns: perturbation analysis for species with minimal demographic data.. Ecology 2000;81:654–665.
  30. Johnson HE, Mills LS, Stephenson TR, Wehausen JD. Population-specific vital rate contributions influence management of an endangered ungulate.. Ecol Appl 2010 Sep;20(6):1753-65.
    pubmed: 20945773doi: 10.1890/09-1107.1google scholar: lookup
  31. Kie JG, White M. Population dynamics of white-tailed deer (Odocoileus virginianus) on the Welder Wildlife Refuge, Texas.. Southwest. Nat. 1985;30:105–118.
  32. Koenen EPC, Aldridge LI, Philipsson J. An overview of breeding objectives for warmblood sport horses.. Livest. Prod. Sci. 2004;88:77–84.
  33. Linklater WL, Cameron EZ, Stafford KJ, Minot EO. Feral horse demography and population growth in the Kaimanawa Ranges, New Zealand.. Wildl. Res. 2004;31:119–128.
  34. McFarland R, Majolo B. Coping with the cold: predictors of survival in wild Barbary macaques, Macaca sylvanus.. Biol Lett 2013 Aug 23;9(4):20130428.
    pmc: PMC3730655pubmed: 23804292doi: 10.1098/rsbl.2013.0428google scholar: lookup
  35. Nelson LJ, Peek JM. Effect of survival and fecundity on rate of increase of elk.. J. Wildl. Manag. 1982;46:535–540.
  36. Ozgul A, Childs DZ, Oli MK, Armitage KB, Blumstein DT, Olson LE, Tuljapurkar S, Coulson T. Coupled dynamics of body mass and population growth in response to environmental change.. Nature 2010 Jul 22;466(7305):482-5.
    pmc: PMC5677226pubmed: 20651690doi: 10.1038/nature09210google scholar: lookup
  37. Portier C, Festa-Bianchet M, Gaillard J-M, Yoccoz NG. Effects of density and weather on survival of bighorn sheep lambs (Ovis canadensis.. J. Zool. 1998;245:271–278.
  38. R Development Core Team. R: A language and environment for statistical computing R Foundation for Statistical Computing.. Austria: Vienna; 2010.
  39. Raithel JD, Kauffman MJ, Pletscher DH. Impact of spatial and temporal variation in calf survival on the growth of elk populations.. J. Wildl. Manag. 2007;71:795–803.
  40. Sæther BE, Bakke Ø. Avian life history variation and contribution of demographic traits to the population growth rate.. Ecology 2000;81:642–653.
  41. Satinoff E. Behavioral thermoregulation in the cold.. Compreh. Physiol. 2011;14:481–505.
  42. Schoener TW. The newest synthesis: understanding the interplay of evolutionary and ecological dynamics.. Science 2011 Jan 28;331(6016):426-9.
    pubmed: 21273479doi: 10.1126/science.1193954google scholar: lookup
  43. Scorolli AL, Cazorla ACL. Demography of feral horses (Equus caballus): a long-term study in Tornquist Park. Argentina.. Wildlife Res. 2010;37:207–214.
  44. Stearns SC. The evolution of life histories.. Oxford: Oxford Univ. Press; 1992. p. 249.
  45. Steenhof K, Kochert MN, Mcdonald TL. Interactive effects of prey and weather on golden eagle reproduction.. J. Anim. Ecol. 1997;66:350–362.
  46. Turchin P. Complex population dynamics: a theoretical/empirical synthesis.. Princeton, NJ: Princeton Univ. Press; 2003. p. 472.
  47. van Beest FM, Uzal A, Vander Wal E, Laforge MP, Contasti AL, Colville D, McLoughlin PD. Increasing density leads to generalization in both coarse-grained habitat selection and fine-grained resource selection in a large mammal.. J Anim Ecol 2014 Jan;83(1):147-56.
    pubmed: 23931034doi: 10.1111/1365-2656.12115google scholar: lookup
  48. Vickery WL, Millar JS. The energetics of huddling by endotherms.. Oikos 1984;43:88–93.
  49. Welsh DA. Population, behavioural and grazing ecology of the horses of Sable Island, Nova Scotia. Ph.D. Thesis.. Halifax, NS: Dalhousie University; 1975.
  50. Wilson L, Barnett W. Degree-days: an aid in crop and pest management.. Calif. Agric. 1983;37:4–7.
  51. Zuur A, Ieno EN, Walker N, Saveliev AA, Smith GM. Mixed effects models and extensions in ecology with R.. New York, NY: Springer; 2009. p. 574.

Citations

This article has been cited 8 times.
  1. Medill SA, Janz DM, McLoughlin PD. Hair Cortisol Concentrations in Feral Horses and the Influence of Physiological and Social Factors. Animals (Basel) 2023 Jun 27;13(13).
    doi: 10.3390/ani13132133pubmed: 37443930google scholar: lookup
  2. Mott R, Prowse TAA, Jackson MV, Rogers DJ, O'Connor JA, Brookes JD, Cassey P. Measuring habitat quality for waterbirds: A review. Ecol Evol 2023 Apr;13(4):e9905.
    doi: 10.1002/ece3.9905pubmed: 37038530google scholar: lookup
  3. Manning JA, McLoughlin PD. Environmental and demographic drivers of male mating success vary across sequential reproductive episodes in a polygynous breeder. Ecol Evol 2019 May;9(9):5106-5117.
    doi: 10.1002/ece3.5066pubmed: 31110665google scholar: lookup
  4. Remmers JJ, Stodola KW, Allen ML. Fisher (Pekania pennanti) Populations Exhibit Regional Differences in Cause-Specific Mortality but Not Survival Rates. Ecol Evol 2025 Jun;15(6):e71531.
    doi: 10.1002/ece3.71531pubmed: 40486947google scholar: lookup
  5. Bland AL, Plard F, Giura Negru B, Hernández-Pacheco R. Density-dependent feedback across nested levels of organization in a social primate. J Anim Ecol 2025 May;94(5):971-984.
    doi: 10.1111/1365-2656.70028pubmed: 40091536google scholar: lookup
  6. Stothart MR, McLoughlin PD, Medill SA, Greuel RJ, Wilson AJ, Poissant J. Methanogenic patterns in the gut microbiome are associated with survival in a population of feral horses. Nat Commun 2024 Jul 22;15(1):6012.
    doi: 10.1038/s41467-024-49963-xpubmed: 39039075google scholar: lookup
  7. Rödel HG, Ibler B, Ozogány K, Kerekes V. Age-specific effects of density and weather on body condition and birth rates in a large herbivore, the Przewalski's horse. Oecologia 2023 Dec;203(3-4):435-451.
    doi: 10.1007/s00442-023-05477-9pubmed: 37971561google scholar: lookup
  8. Mellish MA, Lucas Z, Lancaster L, Stull JW, Floyd A. Visual and morphometric description of feral horse hooves from Sable Island National Park Reserve. Can Vet J 2023 Nov;64(11):1028-1034.
    pubmed: 37915781
Subscribe to our newsletter
Join 99,727 horse owners like you who receive our email updates on horse health and nutrition.