A comparison of created and natural wetlands in Pennsylvania, USA

Published source details Campbell D.A., Cole C.A. & Brooks R.P. (2002) A comparison of created and natural wetlands in Pennsylvania, USA. Wetlands Ecology and Management, 10, 41-49.
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This study is summarised as evidence for the following.

	Action	Category
	Restore/create freshwater marshes or swamps (specific action unclear) Action Link

Restore/create freshwater marshes or swamps (specific action unclear)

A replicated, site comparison study in 1995 of 26 freshwater marshes in Pennsylvania, USA (Campbell et al. 2002) found that created marshes developed a wetland-characteristic plant community after 10 years, but had lower plant species richness and vegetation cover than reference (disturbed and pristine) marshes for up to 18 years. The overall plant community in >10-year-old created sites was characteristic of true wetlands, just like the community in reference wetlands. However, the overall plant community in <10-year-old created sites was characteristic of significantly drier conditions (data reported as a wetland indicator index). Regardless of age, created wetlands had a lower average plant species richness (3–6 species/79 m²) and vegetation cover (65–75%) than reference wetlands (10 species/79 m²; 95% cover). Methods: In June–August 1995, vegetation was surveyed across 26 freshwater marshes. Twelve marshes (0.2–5.3 ha) had been created in uplands approximately 2–18 years previously. The study does not report details of wetland creation methods. Fourteen reference marshes (0.1–2.1 ha), ranging from “disturbed” to “pristine”, were used for comparison. Plant species were recorded in 5-m radius circular plots, spaced 20 m apart across the whole of each wetland. Vegetation cover was recorded in a 0.25-m² quadrat within each plot.

(Summarised by: Nigel Taylor)