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Dynamics or constancy in Sphagnum dominated mire ecosystems? A 40-year study

Gunnarsson, U; Malmer, Nils LU and Rydin, H (2002) In Ecography1992-01-01+01:00 25(6). p.685-704
Abstract
Traditionally mire ecosystems (especially bogs) have been viewed as stable systems with slow changes in the vegetation over time. In this study the mire Akhultmyren, south-central Sweden was re-investigated in 1997 after 40 yr of continued natural development. The results show a high degree of dynamics in a Sphagnum dominated bog and fen. Altogether 97 vascular plant and bryophyte species were recorded in the two inventories of the bog and poor fen vegetation. pH and electrical conductivity in the mire water were also surveyed. In 1997 we found 10 new species and that 8 species had disappeared since 1954 but the over-all mean number of species per plot (size 400 m(2)) had hardly changed. However, 21% of the species increased and 21%... (More)
Traditionally mire ecosystems (especially bogs) have been viewed as stable systems with slow changes in the vegetation over time. In this study the mire Akhultmyren, south-central Sweden was re-investigated in 1997 after 40 yr of continued natural development. The results show a high degree of dynamics in a Sphagnum dominated bog and fen. Altogether 97 vascular plant and bryophyte species were recorded in the two inventories of the bog and poor fen vegetation. pH and electrical conductivity in the mire water were also surveyed. In 1997 we found 10 new species and that 8 species had disappeared since 1954 but the over-all mean number of species per plot (size 400 m(2)) had hardly changed. However, 21% of the species increased and 21% decreased significantly in frequency. Most of the species that decreased in frequency were low-grown vascular plants, most common in wet microhabitats. Vascular plant species that increased in frequency included trees (defined as > 1.3 m in height) and were generally taller than the unchanged or decreasing species. The frequency of dwarf shrubs and hummock bryophytes increased too. Areas with an initial pH of 4.5-5.0 showed the strongest decrease in pH, coinciding with an enlarged distribution of some Sphagnum species. The species diversity increased on the bog, but decreased in the wettest parts of the fen, where the pH also decreased. Species with unchanged or increasing frequency often showed high capacity to colonise new plots. On average the sum of gains and losses of species in the plots in 1997 was ca 50% of the species number in 1954. The vegetation changes indicate a drier mire surface and an increased availability of nitrogen. The increased tree cover may have triggered further changes in the plant cover. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Ecography1992-01-01+01:00
volume
25
issue
6
pages
685 - 704
publisher
Wiley-Blackwell
external identifiers
  • wos:000180235900005
  • scopus:0036943499
ISSN
1600-0587
DOI
10.1034/j.1600-0587.2002.250605.x
language
English
LU publication?
yes
id
4ce1bedd-b65b-4c18-b362-6900a90e696f (old id 137709)
date added to LUP
2007-07-02 10:32:32
date last changed
2017-10-29 04:21:33
@article{4ce1bedd-b65b-4c18-b362-6900a90e696f,
  abstract     = {Traditionally mire ecosystems (especially bogs) have been viewed as stable systems with slow changes in the vegetation over time. In this study the mire Akhultmyren, south-central Sweden was re-investigated in 1997 after 40 yr of continued natural development. The results show a high degree of dynamics in a Sphagnum dominated bog and fen. Altogether 97 vascular plant and bryophyte species were recorded in the two inventories of the bog and poor fen vegetation. pH and electrical conductivity in the mire water were also surveyed. In 1997 we found 10 new species and that 8 species had disappeared since 1954 but the over-all mean number of species per plot (size 400 m(2)) had hardly changed. However, 21% of the species increased and 21% decreased significantly in frequency. Most of the species that decreased in frequency were low-grown vascular plants, most common in wet microhabitats. Vascular plant species that increased in frequency included trees (defined as > 1.3 m in height) and were generally taller than the unchanged or decreasing species. The frequency of dwarf shrubs and hummock bryophytes increased too. Areas with an initial pH of 4.5-5.0 showed the strongest decrease in pH, coinciding with an enlarged distribution of some Sphagnum species. The species diversity increased on the bog, but decreased in the wettest parts of the fen, where the pH also decreased. Species with unchanged or increasing frequency often showed high capacity to colonise new plots. On average the sum of gains and losses of species in the plots in 1997 was ca 50% of the species number in 1954. The vegetation changes indicate a drier mire surface and an increased availability of nitrogen. The increased tree cover may have triggered further changes in the plant cover.},
  author       = {Gunnarsson, U and Malmer, Nils and Rydin, H},
  issn         = {1600-0587},
  language     = {eng},
  number       = {6},
  pages        = {685--704},
  publisher    = {Wiley-Blackwell},
  series       = {Ecography1992-01-01+01:00},
  title        = {Dynamics or constancy in Sphagnum dominated mire ecosystems? A 40-year study},
  url          = {http://dx.doi.org/10.1034/j.1600-0587.2002.250605.x},
  volume       = {25},
  year         = {2002},
}