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Providing evidence to improve practice

Individual study: A functional trait approach to fen restoration analysis

Published source details

Hedberg P., Saetre P., Sundberg S., Rydin H. & Kotowski W. (2013) A functional trait approach to fen restoration analysis. Applied Vegetation Science, 16, 658-666


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Cut/remove/thin forest plantations Peatland Conservation

A replicated, paired, controlled, site comparison study in 2002–2010 involving three tree-colonized rich fens in Sweden (Hedberg et al. 2013) reported that tree removal increased plant species richness, especially in drained plots, but found that it had no effect on the height of new vegetation. Amongst plots that remained drained, those that were clear-cut had higher plant species richness after eight years than those that remained forested (clear-cut: 13; forested: 9 species/0.25 m2). Amongst rewetted plots, tree removal had a much smaller effect (clear-cut: 13; forested: 14 species/0.25 m2). These results were not tested for statistical significance. Tree removal had no significant effect on canopy height (of new vegetation) in drained plots (clear-cut: 6 m; forested: 6 m) or rewetted plots (clear-cut: 5 m; forested: 5 m). For comparison, a nearby natural (undrained and unforested) fen contained 9 plant species/0.25 m2 and had a canopy height of 1 m. These were significantly greater in the clear-cut plots. Around winter 2002/2003, trees were removed from one 50 x 300 m plot in each tree-colonized fen. An adjacent plot was left forested. Half of each plot was also rewetted whilst half remained drained. In 2010, plant species and canopy height were recorded at 40 points/plot, in 0.25 m2 quadrats. The natural fen was sampled in 1978. This study was based on the same experimental set-up as (2) and (3).

(Summarised by Nigel Taylor)

Cut/remove/thin forest plantations and rewet peat Peatland Conservation

A replicated, paired, controlled, site comparison study in 2002–2010 involving three degraded rich fens in Sweden (Hedberg et al. 2013) reported that clear-cut and rewetted plots developed greater plant species richness than plots that remained forested and drained, but that vegetation grew to a similar height. Most of these results were not tested for statistical significance. After eight years, clear-cut and rewetted plots contained 14 species/0.25 m2, compared to 9 species/0.25 m2 in plots that remained forested and drained. Canopy height (of vegetation that grew following intervention) in clear-cut/rewetted plots was 5 m, compared to 6 m in drained/forested plots. Plots only rewetted or cleared had similar species richness (13–14 species/0.25 m2) and vegetation height (5–6 m) to the plots both rewetted and cleared. For comparison, a nearby natural (undrained and unforested) fen contained 9 plant species/0.25 m2 and had a canopy height of 1 m. These were significantly greater in the clear-cut/rewetted plots. Around winter 2002/2003, four restoration treatments were applied in each drained and tree-colonized fen, in adjacent 50 x 150 m plots: cutting and removal of all trees, rewetting (by ditch blocking), tree removal and rewetting, or none. In 2010, plant species and canopy height were recorded at 20 points/plot, in 0.25 m2 quadrats. The natural fen was sampled in 1978. This study was based on the same experimental set-up as (3) and (6).

(Summarised by Nigel Taylor)

Rewet peatland (raise water table) Peatland Conservation

A replicated, paired, controlled, before-and-after, site comparison study in 2002–2010 involving three degraded rich fens in Sweden (Hedberg et al. 2013) reported that rewetting increased plant species richness but found that it had no effect on vegetation height. After eight years, rewetted plots had higher plant species richness than drained plots (not tested for statistical significance). This effect was larger in plots that remained forested (rewetted: 13; drained: 9 species/0.25 m2) than in plots previously cleared of trees (rewetted: 14; drained: 13 species/0.25 m2). Rewetting had no effect on vegetation height: it was similar in both treatments after eight years (rewetted: 5–6 m; drained: 5–6 m) and did not change significantly over time (data not reported). For comparison, a nearby natural (undrained and unforested) fen contained 9 plant species/0.25 m2 and had a canopy height of 1 m. These were significantly greater in the rewetted plots. In winter 2002/2003 at each of three sites, two adjacent 100 x 150 m plots were established: one rewetted above a ditch blockage, and one drained below. Trees were also removed from half of each plot. Before intervention in 2002, then until 2010, plant species and canopy height (ignoring trees present before intervention) were recorded at 40 points/plot, in 0.25 m2 quadrats. The natural fen was sampled in 1978. This study was based on the same experimental set-up as (13) and (18).

(Summarised by Nigel Taylor)