Recovery of target bryophytes in floating rich fens after 25 yr of inundation by base-rich surface water with lower nutrient contents

Published source details Kooijman A.M., Cusell C., Mettrop I.S. & Lamers L.P.M. (2016) Recovery of target bryophytes in floating rich fens after 25 yr of inundation by base-rich surface water with lower nutrient contents. Applied Vegetation Science, 19, 53-65.
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This study is summarised as evidence for the following.

	Action	Category
	Slow down input water to allow more time for pollutants to be removed Action Link
	Clean waste water before it enters the environment Action Link
	Divert/replace polluted water source(s) Action Link

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

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.

(Summarised by: Nigel Taylor)
Clean waste water before it enters the environment

A study in 1984–2013 in a floating rich fen in the Netherlands (Kooijman et al. 2016) found that after installing water purification facilities (along with other interventions to reduce pollution), moss cover changed to species characteristic of lower nutrient levels whilst vascular plant biomass decreased. Over 25 years following intervention, four of seven moss species characteristic of low nutrient levels increased in cover (from 1–62% to 11–83%). Meanwhile, six of seven moss species characteristic of high nutrient levels decreased in cover (from 7–78% to 1–32%). Over 28 years, vascular plant biomass decreased from 1,123 g/m² to 287 g/m². Since the 1970s, water purification facilities were built to treat the fen water source (no further details reported), the water source was changed from a nutrient-rich river to a nutrient-poor lake, and the water was rerouted to allow more time for nutrient reduction. The study does not distinguish between the effects of these interventions. In addition, there was a general reduction in nutrient input from urban areas. 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.

(Summarised by: Nigel Taylor)
Divert/replace polluted water source(s)

A study in 1984–2013 in a floating rich fen in the Netherlands (Kooijman et al. 2016) found that after replacing a nutrient-rich water source with lower-nutrient water (along with other interventions to reduce pollution), moss cover changed to species characteristic of lower nutrient levels and vascular plant biomass decreased. Over 25 years following intervention, four of seven moss species characteristic of low nutrient levels increased in cover (from 1–62% to 11–83%). Meanwhile, six of seven moss species characteristic of high nutrient levels decreased in cover (from 7–78% to 1–32%). Over 28 years, vascular plant biomass decreased from 1,123 g/m² to 287 g/m². Since the 1970s, the fen water source was changed from a nutrient-rich river to a nutrient-poor lake, the input water was rerouted on a longer path to allow more time for nutrient reduction, and water purification facilities were built. The study does not distinguish between the effects of these interventions. In addition, there was a general reduction in nutrient input from urban areas. 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.

(Summarised by: Nigel Taylor)