Slow down input water to allow more time for pollutants to be removed

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One study evaluated the effects, on peatland vegetation, of slowing down input water to allow more time for pollutants to be removed. The study was in a fen.
  • Characteristic plants (1 study): One before-and-after study in a floating fen in the Netherlands found that after input water was rerouted on a longer path (along with other interventions to reduce pollution), cover of mosses characteristic of low nutrient levels increased.
  • Vegetation structure (1 study): The same study found that after input water was rerouted on a longer path (along with other interventions to reduce pollution), vascular plant biomass decreased.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A before-and-after study in 1984–2013 in a floating rich fen in the Netherlands (Kooijman et al. 2016) found that after rerouting input water on a longer path (along with other interventions to reduce pollution), moss cover changed to species characteristic of lower nutrient levels, whilst vascular plant biomass decreased. Four of seven moss species characteristic of low nutrient levels increased in cover (from 1–62% four years before ditch extension to 11–83% eleven years after). Meanwhile, six of seven moss species characteristic of high nutrient levels decreased in cover (from 7–78% to 1–32%). Vascular plant biomass decreased from 1,123 g/m2 eight years before ditch extension to 287 g/m2 ten years after. In 1992, water entering the fen was rerouted on a longer path to allow more time for nutrient removal. The study does not distinguish between the effects of this intervention and the long term effects of two other interventions carried out since the 1970s: use of water purification facilities and switching the water source from a nutrient-rich river to a nutrient-poor lake. In 1988 and 2013, cover of every moss species was recorded in a 25 x 200 m area. In 1984 and 2012, above-ground vascular plant biomass was collected, dried and weighed.

    Study and other actions tested
Please cite as:

Taylor, N.G., Grillas, P. & Sutherland, W.J. (2020) Peatland Conservation. Pages 367-430 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Peatland Conservation

This Action forms part of the Action Synopsis:

Peatland Conservation
Peatland Conservation

Peatland Conservation - Published 2018

Peatland Conservation

What Works 2021 cover

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What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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