University of Oulu

Hiltunen, T. A., Stien, A., Väisänen, M., Ropstad, E., Aspi, J. O., & Welker, J. M. (2022). Svalbard reindeer winter diets: Long-term dietary shifts to graminoids in response to a changing climate. Global Change Biology, 28, 7009– 7022.

Svalbard reindeer winter diets : long-term dietary shifts to graminoids in response to a changing climate

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Author: Hiltunen, Tamara A.1; Stien, Audun2; Väisänen, Maria1,3;
Organizations: 1Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
2Department of Arctic and Marine Biology, Fram Centre, The Arctic University of Norway, Tromsø, Norway
3Arctic Centre, University of Lapland, Rovaniemi, Finland
4Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Ås, Norway
5UArctic, Rovaniemi, Finland
6Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, USA
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.7 MB)
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Language: English
Published: John Wiley & Sons, 2022
Publish Date: 2022-09-28


Arctic ecosystems are changing dramatically with warmer and wetter conditions resulting in complex interactions between herbivores and their forage. We investigated how Svalbard reindeer (Rangifer tarandus platyrhynchus) modify their late winter diets in response to long-term trends and interannual variation in forage availability and accessibility. By reconstructing their diets and foraging niches over a 17-year period (1995–2012) using serum δ13C and δ15N values, we found strong support for a temporal increase in the proportions of graminoids in the diets with a concurrent decline in the contributions of mosses. This dietary shift corresponds with graminoid abundance increases in the region and was associated with increases in population density, warmer summer temperatures and more frequent rain-on-snow (ROS) in winter. In addition, the variance in isotopic niche positions, breadths, and overlaps also supported a temporal shift in the foraging niche and a dietary response to extreme ROS events. Our long-term study highlights the mechanisms by which winter and summer climate changes cascade through vegetation shifts and herbivore population dynamics to alter the foraging niche of Svalbard reindeer. Although it has been anticipated that climate changes in the Svalbard region of the Arctic would be detrimental to this unique ungulate, our study suggests that environmental change is in a phase where conditions are improving for this subspecies at the northernmost edge of the Rangifer distribution.

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Series: Global change biology
ISSN: 1354-1013
ISSN-E: 1365-2486
ISSN-L: 1354-1013
Volume: 28
Issue: 23
Pages: 7009 - 7022
DOI: 10.1111/gcb.16420
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: The work was supported mainly by grants from U.K. Natural Environment Research Council (GR3/1083), the Norwegian Research Council and the Macaulay Development Trust. Additional financial support has come from the Amundsen Foundation, Centre for Ecology and Hydrology, the Macaulay Institute, NINA, UNIS, and the Norwegian School of Veterinary Science. Funding for JMW was supported by the Distinguished US Arctic Research Chairship-Norway and the Inaugural UArctic Research Chairship. The analyses were made possible in part by a National Science Foundation Major Research Instrumentation award (0953271) to JMW. Funding for TH and MV was supported by JMW's UArctic Research Chairship.
Copyright information: © 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.