Do high iron concentrations in rewetted rich fens hamper restoration?

Published source details Aggenbach C.J.S., Backx H., Emsens W.J., Grootjans A.P., Lamers L.P.M., Smolders A.J.P., Stuyfzand P.J., Wołejko L. & Van Diggelen R. (2013) Do high iron concentrations in rewetted rich fens hamper restoration?. Preslia, 85, 405-420.
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This study is summarised as evidence for the following.

	Action	Category
	Rewet peatland (raise water table) Action Link

Rewet peatland (raise water table)

A replicated site comparison study in 2009 in 11 rich fens in Belgium, Poland and the Netherlands (Aggenbach et al. 2013) found that rewetted fens had similar total plant species richness to fens that had never been drained, but lower fen-characteristic species richness, greater herb cover and lower moss cover. Rewetted fens contained a similar total number of plant species to never-drained fens (27 vs 30 species/25 m²) but fewer fen-characteristic species (7 vs 15 species/25 m²). Rewetted fens had greater overall herb cover (52 vs 28%) and tall sedge/rush cover (41 vs 18%), but less cover of mosses overall (50 vs 90%) and fen-characteristic mosses (4 vs 40%). Cover of fen-characteristic vascular plants was similar in rewetted and never-drained fens (34 vs 33%). In summer 2009, cover of every plant species was estimated in sixteen 25 m² plots: nine plots across five rewetted fens in Belgium and the Netherlands, and seven plots across six never-drained fens in Poland. Details of rewetting were not reported, but the water table in all fens was <10 cm below the peat surface. Plots experienced a range of mowing regimes. The rewetted fens contained more iron and phosphorous than the never-drained fens, which may have affected the vegetation.

(Summarised by: Nigel Taylor)