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

摘要: Individual-based study of natural populations allows for accurate and precise estimation fitness components the extent to which they might vary with ecological conditions. By tracking fates all 701 horses known have lived on Sable Island, Canada, from 2009 2013 (where there is no predation, human interference, or interspecific competition food), we present a detailed analysis structured population dynamics focus interacting effects intraspecific weather reproduction survival. Annual survival adult females (0.866 ± 0.107 [ ± SE]) was lower than that 3-year-olds (0.955 ± 0.051), although annual fecundity (producing foal in year observed during our census) higher adults (0.616 ± 0.023) compared (0.402 ± 0.054). Milder winters densities gestation increased fecundity. Density negatively impacted age sex categories; however, highest female high-density years coupled harsh winter, result expected if pregnancy loss winter foals spring improved Three-year-old females, reproduced at rates, experienced adults. Our results contrast previous feral suggested recently ungulates be artificially selected reproduce even when costs are high. In part, this may because comparably long history feralization (250 years; least 25 generations) Island horses.