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Citation
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HERO ID
3546421
Reference Type
Journal Article
Title
Peatland plant communities under global change: negative feedback loops counteract shifts in species composition
Author(s)
Hedwall, PO; Brunet, J; Rydin, H
Year
2017
Is Peer Reviewed?
Yes
Journal
Ecology
ISSN:
0012-9658
EISSN:
1920-2005
Volume
98
Issue
1
Page Numbers
150-161
Language
English
PMID
28052390
DOI
10.1002/ecy.1627
Web of Science Id
WOS:000391862900023
Abstract
Mires (bogs and fens) are nutrient-limited peatland ecosystems, the vegetation of which is especially sensitive to nitrogen deposition and climate change. The role of mires in the global carbon cycle, and the delivery of different ecosystem services can be considerably altered by changes in the vegetation, which has a strong impact on peat-formation and hydrology. Mire ecosystems are commonly open with limited canopy cover but both nitrogen deposition and increased temperatures may increase the woody vegetation component. It has been predicted that such an increase in tree cover and the associated effects on light and water regimes would cause a positive feed-back loop with respect to the ground vegetation. None of these effects, however, have so far been confirmed in large-scale spatiotemporal studies. Here we analyzed data pertaining to mire vegetation from the Swedish National Forest Inventory collected from permanent sample plots over a period of 20 yr along a latitudinal gradient covering 14°. We hypothesized that the changes would be larger in the southern parts as a result of higher nitrogen deposition and warmer climate. Our results showed an increase in woody vegetation with increases in most ericaceous dwarf-shrubs and in the basal area of trees. These changes were, in contrast to our expectations, evenly distributed over most of the latitudinal gradient. While nitrogen deposition is elevated in the south, the increase in temperatures during recent decades has been larger in the north. Hence, we suggest that different processes in the north and south have produced similar vegetation changes along the latitudinal gradient. There was, however, a sharp increase in compositional change at high deposition, indicating a threshold effect in the response. Instead of a positive feed-back loop caused by the tree layer, an increase in canopy cover reduced the changes in composition of the ground vegetation, whereas a decrease in canopy cover lead to larger changes. Increased natural disturbances of the tree layer due to, for example, pathogens or climate is a predicted outcome of climate change. Hence, these results may have important implications for predictions of long-term effects of increased temperature on peatland vegetation.
Tags
NAAQS
•
ISA NOxSOxPM Ecology (2018)
Cited in the Second Draft
Appendix 11
•
ISA NOxSOxPM Ecology (2020- Final Project Page)
Cited
Appendix 11
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