title: Rough-legged buzzards, Arctic foxes and red foxes in a tundra ecosystem without rodents.
abstract: Small rodents with multi-annual population cycles strongly influence the dynamics of food webs, and in particular predator-prey interactions, across most of the tundra biome. Rodents are however absent from some arctic islands, and studies on performance of arctic predators under such circumstances may be very instructive since rodent cycles have been predicted to collapse in a warming Arctic. Here we document for the first time how three normally rodent-dependent predator species-rough-legged buzzard, arctic fox and red fox - perform in a low-arctic ecosystem with no rodents. During six years (in 2006-2008 and 2011-2013) we studied diet and breeding performance of these predators in the rodent-free Kolguev Island in Arctic Russia. The rough-legged buzzards, previously known to be a small rodent specialist, have only during the last two decades become established on Kolguev Island. The buzzards successfully breed on the island at stable low density, but with high productivity based on goslings and willow ptarmigan as their main prey - altogether representing a novel ecological situation for this species. Breeding density of arctic fox varied from year to year, but with stable productivity based on mainly geese as prey. The density dynamic of the arctic fox appeared to be correlated with the date of spring arrival of the geese. Red foxes breed regularly on the island but in very low numbers that appear to have been unchanged over a long period - a situation that resemble what has been recently documented from Arctic America. Our study suggests that the three predators found breeding on Kolguev Island possess capacities for shifting to changing circumstances in low-arctic ecosystem as long as other small - medium sized terrestrial herbivores are present in good numbers.
authors.affiliation: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Am Obstberg 1, D-78315, Radolfzell, Germany.
authors.forename: Ivan
authors.initials: I
authors.lastname: Pokrovsky
authors.affiliation: Department of Arctic and Marine Biology, University of Tromsø, NO-9037, Tromsø, Norway.
authors.forename: Dorothée
authors.initials: D
authors.lastname: Ehrich
authors.affiliation: Department of Arctic and Marine Biology, University of Tromsø, NO-9037, Tromsø, Norway.
authors.forename: Rolf A
authors.initials: RA
authors.lastname: Ims
authors.affiliation: Institute of Biological Problems of the North, Far-East Branch Russian Academy of Sciences, 685000, Portovaya str. 18, Magadan, Russia.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kondratyev
authors.affiliation: Institute for Waterbird and Wetlands Research IWWR e.V., Am Steigbügel 3, D-27283, Verden (Aller), Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Kruckenberg
authors.affiliation: Faculty of Geography, Lomonosov Moscow State University, GSP-1, Leninskie Gory, RU-119991, Moscow, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Kulikova
authors.affiliation: Faculty of Biology, Lomonosov Moscow State University, GSP-1, Leninskie Gory, RU-119991, Moscow, Russia.
authors.forename: Julia
authors.initials: J
authors.lastname: Mihnevich
authors.affiliation: Faculty of Biology, Lomonosov Moscow State University, GSP-1, Leninskie Gory, RU-119991, Moscow, Russia.
authors.forename: Liya
authors.initials: L
authors.lastname: Pokrovskaya
authors.affiliation: Faculty of Biology, Lomonosov Moscow State University, GSP-1, Leninskie Gory, RU-119991, Moscow, Russia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Shienok
mesh_terms: D000818:Animals; D001110:Arctic Regions; D025061:Dinosaurs / Q000502:physiology*; D005589:Foxes / Q000502:physiology*; D009425:Nesting Behavior; D011157:Population Dynamics; D011235:Predatory Behavior; D065929:Tundra