6.9.1 Multiple sources of pollution

Likely to be beneficial

Divert/replace polluted water source (s)

1• Characteristic plants: One study in a fen in the Netherlands found that after a nutrient-enriched water source was replaced, along with other interventions to reduce pollution, cover of mosses characteristic of low nutrient levels increased.

2• Vegetation cover: Two studies in bogs in the UK and Japan reported that after polluting water sources were diverted, sometimes along with other interventions, Sphagnum moss cover increased. Both studies reported mixed effects on different species of herbs.

3• Assessment: likely to be beneficial (effectiveness 70 %; certainty 50 %; harms 10 %). Based on evidence from: bogs (two studies); fens (one study).

4https://www.conservationevidence.com/actions/1779

Unknown effectiveness (limited evidence)

Clean waste water before it enters the environment

5• Characteristic plants: One study in the Netherlands found that cleaning water entering a floating fen, along with other interventions to reduce pollution, allowed cover of mosses characteristic of low nutrient levels to increase.

6• Vegetation structure: The same study found that after the input water began to be cleaned, along with other interventions to reduce pollution, vascular plant biomass decreased.

7• Assessment: unknown effectiveness – limited evidence (effectiveness 60 %; certainty 25 %; harms 0 %). Based on evidence from: fens (one study).

8https://www.conservationevidence.com/actions/1778

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

9• Characteristic plants: 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.

10• Vegetation structure: The same study found that after the input water was rerouted on a longer path, along with other interventions to reduce pollution, vascular plant biomass decreased.

11• Assessment: unknown effectiveness – limited evidence (effectiveness 50 %; certainty 20 %; harms 5 %). Based on evidence from: fens (one study).

12https://www.conservationevidence.com/actions/1780

No evidence found (no assessment)

13We have captured no evidence for the following interventions:

• Retain or create buffer zones between pollution sources and peatlands
• Use artificial barriers to prevent pollution entering peatlands
• Reduce fertilizer or herbicide use near peatlands
• Manage fertilizer or herbicide application near peatlands.

6.9.2 Agricultural and aquacultural effluents

No evidence found (no assessment)

14We have captured no evidence for the following interventions:

• Convert to organic agriculture or aquaculture near peatlands
• Limit the density of livestock on farmland near peatlands
• Use biodegradable oil in farming machinery.

6.9.3 Industrial and military effluents

No evidence found (no assessment)

15We have captured no evidence for the following intervention:

• Remove oil from contaminated peatlands.

6.9.4 Airborne pollutants

Unknown effectiveness (limited evidence)

Remove pollutants from waste gases before they enter the environment

16• Plant richness/diversity: One study in bogs in Estonia reported that after dust filters were installed in industrial plants, along with a general reduction in emissions, the number of Sphagnum moss species increased but the total number of plant species decreased.

17• Assessment: unknown effectiveness – limited evidence (effectiveness 50 %; certainty 20 %; harms 0 %). Based on evidence from: bogs (one study).

18https://www.conservationevidence.com/actions/1789

Add lime to reduce acidity and/or increase fertility

19• Vegetation structure: One replicated, controlled study in a fen meadow in the Netherlands found that liming increased overall vegetation biomass (mostly velvety bentgrass Agrostis canina).

20• Assessment: unknown effectiveness – limited evidence (effectiveness 50 %; certainty 15 %; harms 20 %). Based on evidence from: fen meadows (one study).

21https://www.conservationevidence.com/actions/1790

Drain/replace acidic water

22• Vegetation cover: Two controlled studies in fens in the Netherlands reported that draining acidic water had mixed effects on cover of Sphagnum moss and herbs after 4–5 years, depending on the species and whether moss was also removed.

23• Overall plant richness/diversity: One controlled, before-and-after study in a fen in the Netherlands reported that draining and replacing acidic water increased plant species richness.

24• Assessment: unknown effectiveness – limited evidence (effectiveness 40 %; certainty 35 %; harms 10 %). Based on evidence from: fens (two studies).

25https://www.conservationevidence.com/actions/1791