Growth rings show limited evidence for ungulates’ potential to suppress shrubs across the Arctic

• Published in: Environmental Research Letters
• Main Authors: Vuorinen, Katariina, Austrheim, Gunnar, Tremblay, Jean-Pierre, Myers-Smith, Isla H., Hortman, Hans Ivar, Frank, Peter, Barrio, Isabel C., Dalerum, Fredrik, Björkman, Mats P., Björk, Robert G., Ehrich, Dorothee, Sokolov, Aleksandr, Sokolova, Natalia, Ropars, Pascale, Boudreau, Stephane, Normand, Signe, Prendin, Angela Luisa, Schmidt, Niels Martin, Pacheco, Arturo, Post, Eric, John, Christian, Kerby, Jeff T, Sullivan, Patrick F, Le Moullec, Mathilde, Hansen, Brage Bremset, Van der Wal, Rene, Pedersen, Åshild Ønvik, Sandal, Lisa, Gough, Laura, Young, Amanda, Li, Bingxi, Magnússon, Rúna Íris, Sass-Klaassen, Ute, Buchwal, Agata, Welker, Jeffery M, Grogan, Paul, Andruko, Rhett, Morrissette-Boileau, Clara, Volkovitskiy, Alexander, Terekhina, Alexandra, Speed, James David Mervyn
• Other Authors: BIRD Project of TeSAF Department University of Padova, USRA, UK Natural Environment Research Council ShrubTundra Grant, Villum Young Investigator Programme, Darwin Center for Biogeosciences, Canadian Centennial Scholarship Fund, Netherlands Organization for Scientific Research, Wageningen Institute for Environment and Climate Research, NWO Earth and Life Sciences, Norwegian Polar Institute, The Swedish Research Council, National Science Foundation-Arctic Observing Network, Polish-US Fulbright Commission, Toolik Field Station Environmental Data Center, Arctic LTER, Natural Sciences and Engineering Research Council (NSERC) of Canada, Norges Forskningsråd, Russian Fund of Basic Research, Icelandic Research Fund, National Geographic Society for Research and Exploration, Fram Centre, Office of Polar Programs, National Science Foundation, National Science Foundation (United States), Division of Environmental Biology, Aarhus University Research Foundation, Horizon 2020 Framework Programme, Svenska Forskningsrådet Formas, Swedish Research Council for Sustainable Development, State of Alaska Department of Fish and Game, ArcticNet, Ministère des Forêts, de la Faune et des Parcs, Glencore, Hydro Québec, Fédération des pourvoiries du Québec, NSERC Discovery, Makivik Corporation
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: IOP Publishing 2022
• Subjects: Arctic; Global warming; Tundra
• Online Access: http://dx.doi.org/10.1088/1748-9326/ac5207; https://iopscience.iop.org/article/10.1088/1748-9326/ac5207; https://iopscience.iop.org/article/10.1088/1748-9326/ac5207/pdf

Abstract Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional climatic conditions. To study how ungulates interact with temperature to influence growth of tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites, comprising 1,153 individual shrubs and 22,363 annual growth rings. Evidence for ungulates suppressing shrub radial growth was only observed at intermediate summer temperatures (6.5-9°C), and even at these temperatures the effect was not strong. Multiple factors, including forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly explaining the weakness of observed ungulate effects. Earlier local studies have shown that ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate that ungulates’ potential to suppress shrub radial growth is not always evident, and may be limited to certain climatic conditions.