How effective are reedbeds, ponds, restored and constructed wetlands at retaining nitrogen, phosphorus and suspended sediment from agricultural pollution in England?

Table 1 Definition of components of the primary systematic review question

Subject (Population)	Intervention	Comparator	Outcome
Water bodies receiving:	Wetland:	• Input vs output concentration to wetland	1°: Percentage change in water quality measure
• Nitrogen (N)	• Constructed/treatment	• No wetland vs with wetland present	2°: Change in other parameters, including biodiversity measures and greenhouse gas emission; are there any synergies/trade-offs, e.g. flood risk?
• Phosphorus (P)	• Restored	• Before wetland vs with wetland present
• Suspended solids/sediment (SS)	• Reedbeds
	• Ponds

ISSN: 2047-2382