Reindeer control over shrubification in subarctic wetlands : spatial analysis based on unoccupied aerial vehicle imagery
(2023) In Remote Sensing in Ecology and Conservation 9(5). p.687-706- Abstract
Herbivores can exert a controlling effect on the reproduction and growth of shrubs, thereby counter-acting the climate-driven encroachment of shrubs in the Arctic and the potential consequences. This control is particularly evident in the case of abundant herbivores, such as reindeer (Rangifer tarandus tarandus), whose grazing patterns are affected by management. Here, we tested how different reindeer grazing practices on the border between Finland and Norway impact the occurrence of willow (Salix spp.) dominated patches, their above-ground biomass (AGB) and the ability of willows to form dense thickets. We used a combination of multispectral and RGB imagery obtained from unoccupied aerial vehicles field data and an ensemble of... (More)
Herbivores can exert a controlling effect on the reproduction and growth of shrubs, thereby counter-acting the climate-driven encroachment of shrubs in the Arctic and the potential consequences. This control is particularly evident in the case of abundant herbivores, such as reindeer (Rangifer tarandus tarandus), whose grazing patterns are affected by management. Here, we tested how different reindeer grazing practices on the border between Finland and Norway impact the occurrence of willow (Salix spp.) dominated patches, their above-ground biomass (AGB) and the ability of willows to form dense thickets. We used a combination of multispectral and RGB imagery obtained from unoccupied aerial vehicles field data and an ensemble of machine-learning models, which allowed us to model the occurrence of plant community types (Overall accuracy = 0.80), AGB fractions (maximum R2 = 0.90) and topsoil moisture (maximum R2 = 0.89). With this combination of approaches, we show that willows are kept in a browsing-trap under spring and early summer grazing by reindeer, growing mostly small and scattered in the landscape. In contrast, willows under the winter grazing regime formed dense stands, particularly within riparian areas. We confirm this pattern using a random forest willow habitat distribution model based on topographical parameters. The model shows that willow biomass correlated with parameters of optimal habitat quality only in the winter grazing regime and did not respond to the same parameters under spring and summer grazing of reindeer.
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- author
- Villoslada, Miguel ; Ylänne, Henni LU ; Juutinen, Sari ; Kolari, Tiina H.M. ; Korpelainen, Pasi ; Tahvanainen, Teemu ; Wolff, Franziska and Kumpula, Timo
- publishing date
- 2023-05-09
- type
- Contribution to journal
- publication status
- published
- keywords
- Arctic greening, fens, herbivory, shrubification, UAV
- in
- Remote Sensing in Ecology and Conservation
- volume
- 9
- issue
- 5
- pages
- 20 pages
- publisher
- Wiley-Blackwell
- external identifiers
-
- scopus:85158100390
- ISSN
- 2056-3485
- DOI
- 10.1002/rse2.337
- language
- English
- LU publication?
- no
- additional info
- Funding Information: We would like to thank Aleksi Pantsar, Laura Oinas and Thaísa F. Bergamo for their assistance during the field data collection process. This work was supported by Academy of Finland (project nrs: 330319 and 330845) and EU Horizon 2020 (project nr: 2020 869471). Funding Information: This work was supported by Academy of Finland (project nr: 330319 to T. Kumpula and 330845 to H. Ylänne) and EU Horizon 2020 (project nr: 2020 869471 to B. Forbes). Publisher Copyright: © 2023 The Authors. Remote Sensing in Ecology and Conservation published by John Wiley & Sons Ltd on behalf of Zoological Society of London.
- id
- 3e0cbb11-2c4b-4286-9e1a-cd93fea74839
- date added to LUP
- 2023-06-12 11:16:32
- date last changed
- 2024-01-09 15:47:17
@article{3e0cbb11-2c4b-4286-9e1a-cd93fea74839,
abstract = {{<p>Herbivores can exert a controlling effect on the reproduction and growth of shrubs, thereby counter-acting the climate-driven encroachment of shrubs in the Arctic and the potential consequences. This control is particularly evident in the case of abundant herbivores, such as reindeer (Rangifer tarandus tarandus), whose grazing patterns are affected by management. Here, we tested how different reindeer grazing practices on the border between Finland and Norway impact the occurrence of willow (Salix spp.) dominated patches, their above-ground biomass (AGB) and the ability of willows to form dense thickets. We used a combination of multispectral and RGB imagery obtained from unoccupied aerial vehicles field data and an ensemble of machine-learning models, which allowed us to model the occurrence of plant community types (Overall accuracy = 0.80), AGB fractions (maximum R<sup>2</sup> = 0.90) and topsoil moisture (maximum R<sup>2</sup> = 0.89). With this combination of approaches, we show that willows are kept in a browsing-trap under spring and early summer grazing by reindeer, growing mostly small and scattered in the landscape. In contrast, willows under the winter grazing regime formed dense stands, particularly within riparian areas. We confirm this pattern using a random forest willow habitat distribution model based on topographical parameters. The model shows that willow biomass correlated with parameters of optimal habitat quality only in the winter grazing regime and did not respond to the same parameters under spring and summer grazing of reindeer.</p>}},
author = {{Villoslada, Miguel and Ylänne, Henni and Juutinen, Sari and Kolari, Tiina H.M. and Korpelainen, Pasi and Tahvanainen, Teemu and Wolff, Franziska and Kumpula, Timo}},
issn = {{2056-3485}},
keywords = {{Arctic greening; fens; herbivory; shrubification; UAV}},
language = {{eng}},
month = {{05}},
number = {{5}},
pages = {{687--706}},
publisher = {{Wiley-Blackwell}},
series = {{Remote Sensing in Ecology and Conservation}},
title = {{Reindeer control over shrubification in subarctic wetlands : spatial analysis based on unoccupied aerial vehicle imagery}},
url = {{http://dx.doi.org/10.1002/rse2.337}},
doi = {{10.1002/rse2.337}},
volume = {{9}},
year = {{2023}},
}