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Predator-mediated apparent competition persists in a rapidly changing Subarctic ecosystem
  • Milly Hong,
  • James Roth,
  • Laura McKinnon
Milly Hong
York University - Keele Campus

Corresponding Author:[email protected]

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James Roth
University of Manitoba
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Laura McKinnon
York University
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The Alternative Prey Hypothesis (APH) states that predators switch to relatively more abundant prey when their main prey is scarce. In the High Arctic, lemming population cycles indirectly affect predation risk on alternative prey such as shorebird nests as they share a main predator, the arctic fox. In this study, we examined the indirect effects of arvicoline rodent cycles on alternative prey in the Subarctic where arctic and red fox coexist as predators of primary (lemmings, voles) and alternative prey (shorebird nests). Using 10 years of field data, our results indicate that interannual variation in daily nest survival of Dunlin was best explained by an interactive effect of arvicoline rodent abundance and arctic fox (not red fox) abundance. During high rodent years, shorebird nest survival appeared to be buffered from variation in arctic fox abundance but when rodents were absent, nest survival declined. We found no relationship between shorebird nest survival and red fox abundance despite red foxes being found in much higher abundance in the study area. Our results indicate that despite the presence of other predators and multiple primary prey species, predator-mediated interactions common to High Arctic sites, still hold true for the Subarctic in regards to the arctic fox, arvicoline rodents and shorebirds.