Soil and vegetation responses to hydrological manipulation in a partially drained polje fen in New Zealand

Published source details Sorrell B.K., Partridge T.R., Clarkson B.R., Jackson R.J., Chagué-Goff C., Ekanayake J., Payne J., Gerbeaux P. & Grainger N.P.J. (2007) Soil and vegetation responses to hydrological manipulation in a partially drained polje fen in New Zealand. Wetlands Ecology and Management, 15, 361-383.
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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 controlled, before-and-after study in 2000–2002 in a degraded fen in New Zealand (Sorrell et al. 2007) reported that following rewetting, total vegetation and upland plant cover decreased whilst wetland plant cover was stable. These results were not tested for statistical significance. Total vegetation cover declined in all four rewetted plots (before rewetting: 95–100%; one year after: 45–95%) but was stable in drained control plots (before: 92–100%; after: 90–100%). For two abundant, non-native, upland species, cover declined in all four rewetted plots (before: 5–40%; after: 0–5%) but was relatively stable in drained plots (before: 5–43%; after: 5–40%). For two abundant native species that only grow in wetlands, cover was stable in all rewetted plots (before: 22–90%; after: 24–90%) and all but one drained plot (where cover dropped from 13 to 0%). In March 2001, four plots within a fen were rewetted by blocking the main fen drain with soil dams. Nine plots remained drained. In 2000 and 2002, vegetation cover was estimated in four 4 m² quadrats/plot.

(Summarised by: Nigel Taylor)