University of Oulu

Richert, J. C., Leffler, A. J., Spalinger, D. E., and Welker, J. M.. 2021. Snowier winters extend autumn availability of high-quality forage for caribou in Arctic Alaska. Ecosphere 12( 7):e03617. 10.1002/ecs2.3617

Snowier winters extend autumn availability of high-quality forage for caribou in Arctic Alaska

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Author: Richert, J. C.1; Leffler, A. J.1; Spalinger, D. E.2,3;
Organizations: 1Department of Natural Resource Management, South Dakota State University, Brookings, South Dakota 57007 USA
2Department of Biological Sciences, University of Alaska, Anchorage, Alaska 99508 USA
3Alaska Department of Fish and Game, Palmer, Alaska, USA
4Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.2 MB)
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Language: English
Published: John Wiley & Sons, 2021
Publish Date: 2021-10-08


Caribou (Rangifer tarandus) rely on the short Arctic growing season to restore body condition, support the demands of lactation, and prepare for the long arctic winter, making them susceptible to even small changes in forage availability or quality. Body condition in the summer and autumn is linked to winter survival rates and fecundity in cows, critical factors in the productivity of caribou populations. Climate change predictions of warmer and wetter northern winters suggest increased snowfall over Alaska’s North Slope, which has recently been verified between 1995 and 2017. However, a comprehensive analysis of how deeper snow will affect caribou forage quality is absent across Alaska. In this study, we quantify how snow depth alters the quality and seasonality of caribou forage using a long-term (24 yr) International Tundra Experiment snow depth manipulation to evaluate how winter climate change scenarios may affect tussock tundra systems in northern Alaska. Deeper snow in prior winters leads to increases in growing season leaf N and digestible protein (DP) in deciduous shrubs (Salix spp. and Betula spp.) and graminoids (Carex spp. and Eriophorum spp.), but not evergreen dwarf shrubs (Rhododendron spp. and Vaccinium spp.). Dry matter digestibility varied among species with small differences (<5%) associated with snow depth. Most striking was the discovery that deeper snow in the prior winter increased the duration of DP levels above the minimum threshold for protein gain in caribou by as much as 25 d in Salix pulchra and 6–9 d in Betula nana and Carex bigelowii in late summer and early autumn. Consequently, deeper winter snow may provide an extended window of opportunity for foraging and the accumulation of lean body mass and fat reserves which promote winter survival and successful calving the following spring and potentially improve the productivity of caribou in northern Alaska.

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Series: Ecosphere
ISSN: 2150-8925
ISSN-E: 2150-8925
ISSN-L: 2150-8925
Volume: 12
Issue: 7
Article number: e03617
DOI: 10.1002/ecs2.3617
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: South Dakota Agriculture Experiment Station. Grant Number: SD00H550-15; U.S. National Science Foundation. Grant Numbers: ARC1604249, ARC1602440
Dataset Reference: Data are available from the Arctic Data Center:
Copyright information: © 2021 The Authors. 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.