University of Oulu

Ylänne, H., Kaarlejärvi, E., Väisänen, M., Männistö, M. K., Ahonen, S. H. K., Olofsson, J., and Stark, S.. 2019. Removal of grazers alters the response of tundra soil carbon to warming and enhanced nitrogen availability. Ecological Monographs 90(1):e01396. 10.1002/ecm.1396

Removal of grazers alters the response of tundra soil carbon to warming and enhanced nitrogen availability

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Author: Ylänne, Henni1,2,3; Kaarlejärvi, Elina4,5,6; Väisänen, Maria1,7;
Organizations: 1Arctic Center, University of Lapland, P.O. Box 122, Rovaniemi FI-96101 Finland
2Department of Ecology and Genetics, University of Oulu, P.O. Box 3000, FI- 90100 University of Oulu, Finland
3Centre for Environmental and Climate Research, Lund University, P. O. Box 118, SE 221 00 Lund, Sweden
4Department of Ecology and Environmental Sciences, Umeå University, SE- 90187, Sweden
5Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B- 1050 Brussel, Belgium
6Research Centre for Ecological Change, Organismal and Evolutionary Biology, PO Box 65 (Viikinkaari 1), FI-00014 University of Helsinki, Finland
7Current address: Department of Ecology and Genetics, University of Oulu, P.O. Box 3000, FI- 90100 University of Oulu, Finland
8Natural Resources Institute Finland (Luke), Eteläranta 55, 96300 Rovaniemi, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, )
Persistent link: http://urn.fi/urn:nbn:fi-fe202001142075
Language: English
Published: John Wiley & Sons, 2020
Publish Date: 2020-01-14
Description:

Abstract

The circumpolar Arctic is currently facing multiple global changes that have the potential to alter the capacity of tundra soils to store carbon. Yet, predicting changes in soil carbon is hindered by the fact that multiple factors simultaneously control processes sustaining carbon storage and we do not understand how they act in concert. Here, we investigated the effects of warmer temperatures, enhanced soil nitrogen availability, and the combination of these on tundra carbon stocks at three different grazing regimes: on areas with over 50‐yr history of either light or heavy reindeer grazing and in 5‐yr‐old exlosures in the heavily grazed area. In line with earlier reports, warming generally decreased soil carbon stocks. However, our results suggest that the mechanisms by which warming decreases carbon storage depend on grazing intensity: under long‐term light grazing soil carbon losses were linked to higher shrub abundance and higher enzymatic activities, whereas under long‐term heavy grazing, carbon losses were linked to drier soils and higher enzymatic activities. Importantly, under enhanced soil nitrogen availability, warming did not induce soil carbon losses under either of the long‐term grazing regimes, whereas inside exclosures in the heavily grazed area, also the combination of warming and enhanced nutrient availability induced soil carbon loss. Grazing on its own did not influence the soil carbon stocks. These results reveal that accounting for the effect of warming or grazing alone is not sufficient to reliably predict future soil carbon storage in the tundra. Instead, the joint effects of multiple global changes need to be accounted for, with a special focus given to abrupt changes in grazing currently taking place in several parts of the Arctic.

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Series: Ecological monographs
ISSN: 0012-9615
ISSN-E: 1557-7015
ISSN-L: 0012-9615
Volume: 90
Issue: 1
Article number: e01396
DOI: 10.1002/ecm.1396
OADOI: https://oadoi.org/10.1002/ecm.1396
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Subjects:
SEM
Funding: Financial support to the work has been provided by the Academy of Finland (decision numbers 218121 and 130507 to S. Stark and decision number 310776 to Max Häggblom), Maj and Tor Nessling Foundation (to S. Stark), Kone Foundation (to H. Ylänne), the Swedish Research Council (2015‐00498 to E. Kaarlejärvi), Lapland Regional Fund of Finnish Cultural Foundation (to M. Väisänen), and Northern Ostrobothnian Regional Fund of Finnish Cultural Foundation (to H. Ylänne).
Copyright information: © 2019 by the Ecological Society of America. This is the early online version of the following article: Ylänne, H., Kaarlejärvi, E., Väisänen, M., Männistö, M. K., Ahonen, S. H. K., Olofsson, J., and Stark, S.. 2019. Removal of grazers alters the response of tundra soil carbon to warming and enhanced nitrogen availability. Ecological Monographs 00( 00):e01396., which has been published in final form at https://doi.org/10.1002/ecm.1396.