University of Oulu

Stark, S, Ylänne, H, Kumpula, J. Recent changes in mountain birch forest structure and understory vegetation depend on the seasonal timing of reindeer grazing. J Appl Ecol. 2021; 58: 941– 952. https://doi.org/10.1111/1365-2664.13847

Recent changes in mountain birch forest structure and understory vegetation depend on the seasonal timing of reindeer grazing

Saved in:
Author: Stark, Sari1; Ylänne, Henni1,2,3; Kumpula, Jouko4
Organizations: 1Arctic Centre, University of Lapland, Pohjoisranta 4, FI-96100 Rovaniemi, Finland
2University of Oulu, Department of Ecology and Genetics, Pentti Kaiteran katu 1, FI-90100 Oulu, Finland,
3present address: Centre for Environmental and Climate Research, Lund University, Sölvegatan 37, SE-223 62 Lund, Sweden
4Natural Resource Institute Finland (Luke), Inari Station, FI-99870 Inari, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe2021070541125
Language: English
Published: John Wiley & Sons, 2021
Publish Date: 2022-02-09
Description:

Abstract

1: Subarctic forest-tundra ecotones dominated by mountain birch (Betula pubescens ssp. czerepanovii) are an important habitat for semi-domestic reindeer Rangifer tarandus. The seasonal timing of reindeer grazing may direct vegetation trajectories in these systems, because in the summer ranges, mountain birches are subjected to browsing, while in the winter ranges, reindeer feed on understorey vegetation and arboreal lichens but leave the mountain birches intact.

2: Based on earlier research, we predicted that (a) summer browsing dampens ongoing vegetation ‘shrubification’ in semi-dry and dry mountain birch forests and (b) ‘shrubification’ is accompanied by a decline in lichens. We tested these predictions through re-analysing forest structure and understorey vegetation after 12 years in areas where winter and summer ranges had been separated since the 1980s. We also tested how changes in lichen abundances align with changes in shrub abundances through correlation analyses.

3: The number of tall mountain birch seedlings had increased twice as fast in winter than summer ranges, while big mountain birches had increased in summer ranges. The dominant evergreen dwarf shrub mountain crowberry (Empetrum nigrum ssp. hermaphroditum) had increased to a greater extent in winter ranges in a semidry habitat, and to a greater extent in summer ranges in a dry habitat. Deciduous dwarf shrub and graminoid biomass had increased similarly in summer and winter ranges.

4: We found no evidence to support that increasing shrub abundances had contributed to a decline in lichens; instead, the lichen cover increased with increasing number of mountain birch seedlings.

5: Synthesis and application. The vegetation trajectories of dry and semi-dry subarctic mountain birch forests depend greatly on whether the area is used as a winter or a summer range for the reindeer. The recent changes in vegetation are likely to lead to improved summer forage availability for the reindeer, while the opposite may be true for the winter forage availability.

see all

Series: Journal of applied ecology
ISSN: 0021-8901
ISSN-E: 1365-2664
ISSN-L: 0021-8901
Volume: 58
Issue: 5
Pages: 941 - 952
DOI: 10.1111/1365-2664.13847
OADOI: https://oadoi.org/10.1111/1365-2664.13847
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Subjects:
Funding: This work was financed by a project fund to S.S. from Maj and Tor Nessling Foundation and by personal grants to H.Y. and S.S. from Finnish Cultural Foundation and Kone Foundation.
Dataset Reference: Data available via the Dryad Digital Repository https://doi.org/10.5061/dryad.4qrfj6q91 (Stark et al., 2021).
  https://doi.org/10.5061/dryad.4qrfj6q91
Copyright information: © 2021 British Ecological Society. This is the peer reviewed version of the following article: Stark, S, Ylänne, H, Kumpula, J. Recent changes in mountain birch forest structure and understory vegetation depend on the seasonal timing of reindeer grazing. J Appl Ecol. 2021; 58: 941– 952, which has been published in final form at https://doi.org/10.1111/1365-2664.13847. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.