title: Exposing the structure of an Arctic food web.
abstract: How food webs are structured has major implications for their stability and dynamics. While poorly studied to date, arctic food webs are commonly assumed to be simple in structure, with few links per species. If this is the case, then different parts of the web may be weakly connected to each other, with populations and species united by only a low number of links. We provide the first highly resolved description of trophic link structure for a large part of a high-arctic food web. For this purpose, we apply a combination of recent techniques to describing the links between three predator guilds (insectivorous birds, spiders, and lepidopteran parasitoids) and their two dominant prey orders (Diptera and Lepidoptera). The resultant web shows a dense link structure and no compartmentalization or modularity across the three predator guilds. Thus, both individual predators and predator guilds tap heavily into the prey community of each other, offering versatile scope for indirect interactions across different parts of the web. The current description of a first but single arctic web may serve as a benchmark toward which to gauge future webs resolved by similar techniques. Targeting an unusual breadth of predator guilds, and relying on techniques with a high resolution, it suggests that species in this web are closely connected. Thus, our findings call for similar explorations of link structure across multiple guilds in both arctic and other webs. From an applied perspective, our description of an arctic web suggests new avenues for understanding how arctic food webs are built and function and of how they respond to current climate change. It suggests that to comprehend the community-level consequences of rapid arctic warming, we should turn from analyses of populations, population pairs, and isolated predator-prey interactions to considering the full set of interacting species.
authors.affiliation: Department of Agricultural Sciences, University of Helsinki Latokartanonkaari 5, FI-00014, Helsinki, Finland.
authors.forename: Helena K
authors.initials: HK
authors.lastname: Wirta
authors.affiliation: Department of Biology, University of Turku Vesilinnantie 5, FI-20014, Turku, Finland.
authors.forename: Eero J
authors.initials: EJ
authors.lastname: Vesterinen
authors.affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University SE-106 91, Stockholm, Sweden.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Hambäck
authors.affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University SE-106 91, Stockholm, Sweden.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Weingartner
authors.affiliation: Department of Bioscience, Aarhus University Ny Munkegade 114, DK-8000, Aarhus, Denmark.
authors.forename: Claus
authors.initials: C
authors.lastname: Rasmussen
authors.affiliation: Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen P.O. Box 11103, 9700 CC, Groningen, The Netherlands ; Arctic Research Centre, Department of Bioscience, Aarhus University Frederiksborgvej 399, DK-4000, Roskilde, Denmark.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Reneerkens
authors.affiliation: Arctic Research Centre, Department of Bioscience, Aarhus University Frederiksborgvej 399, DK-4000, Roskilde, Denmark.
authors.forename: Niels M
authors.initials: NM
authors.lastname: Schmidt
authors.affiliation: Laboratoire Biogéosciences, UMR CNRS 6282, Université de Bourgogne 6 Boulevard Gabriel, 21000, Dijon, France ; Groupe de Recherche en Ecologie Arctique 16 rue de Vernot, 21440, Francheville, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Gilg
authors.affiliation: Department of Agricultural Sciences, University of Helsinki Latokartanonkaari 5, FI-00014, Helsinki, Finland.
authors.forename: Tomas
authors.initials: T
authors.lastname: Roslin
keywords: Calidris; DNA barcoding; Greenland; Hymenoptera; Pardosa; Plectrophenax; Xysticus; generalism; molecular diet analysis; specialism