Breeding geese are the preferred prey of the Arctic fox Vulpes lagopus in the high-Arctic Svalbard archipelago. According
to the apparent competition hypothesis (ACH), less-abundant prey species (e.g. ptarmigan, waders and small passerines)
will experience higher predation rates when breeding in association with the more common prey (geese), due to spill-over
predation by the shared predator. As many of these less-abundant species are endemic and/or red-listed, increased predation
can have negative repercussions on their populations. We used a one-year baited artificial nest study to assess relative nest
predation risk on Svalbard Rock Ptarmigan Lagopus muta hyperborea, small waders (Purple Sandpiper Calidris maritima,
Dunlin Calidris alpina, plovers Charadrius spp., and phalaropes Phalaropus spp.) and Snow bunting Plectrophenax nivalis
in two study locations contrasted by nesting density of Arctic breeding geese (Pink-footed Goose Anser brachyrhynchus
and Barnacle Goose Branta leucopsis). We predicted higher predation risk for the less-abundant species in the study location
with higher goose abundance. However, we found that relative nest predation risk was lower in the study location with
higher goose abundance, thus being compatible with apparent mutualism and/or prey swamping mechanisms. Our results
contrast with those from more structurally complex Arctic ecosystems and suggest that allochtonous subsidies from temperate
ecosystems structure the predation pattern in this high-Arctic tundra ecosystem.
Keywords Apparent competition · Arctic fox V. lagopus · Artificial nest · Predator · Pink-footed Goose · Svalbard
