[1] Univ Copenhagen, Nat Hist Museum Denmark, Ctr Macroecol Evolut & Climate, Univ Pk 15, DK-2100 Copenhagen O, Denmark
[2] Univ Helsinki, Fac Biol & Environm Sci, Helsinki, Finland
[3] Umea Univ, Dept Ecol & Environm Sci, S-90187 Umea, Sweden
[4] Univ Lancaster, Lancaster Environm Ctr, Lancaster LA1 4YQ, England
[5] Chicago Bot Garden, Glencoe, IL 60022 USA
[6] Inst Marine Res, Ecosyst Proc, Bergen, Norway
[7] Lund Univ, Dept Phys Geog & Ecosyst Sci, Solvegatan 12, SE-22362 Lund, Sweden
[8] Univ Vermont, Rubenstein Sch Environm & Nat Resources, Burlington, VT USA
[9] Univ Vermont, Gund Inst Environm, Burlington, VT USA
[10] St Marys Univ, Dept Environm Sci, Halifax, NS, Canada