Development of vegetation in small created wetlands in southeastern Wisconsin

Published source details Reinartz J.A. & Warne e.L. (1993) Development of vegetation in small created wetlands in southeastern Wisconsin. Wetlands, 13, 153-164.
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This study is summarised as evidence for the following.

	Action	Category
	Introduce seeds of non-woody plants: freshwater wetlands Action Link
	Raise water level to restore/create freshwater marshes from other land uses Action Link

Introduce seeds of non-woody plants: freshwater wetlands

A replicated, site comparison study in 1989–1992 of 10 created wetlands in Wisconsin, USA (Reinartz & Warne 1993) reported that wetlands sown with herb (and some shrub) seeds contained a different plant community to unsown wetlands, with greater richness and diversity but similar vegetation cover. Unless specified, statistical significance was not assessed. After 1–2 years, the overall plant community composition differed between sown and unsown wetlands (data reported as a graphical analysis). Sown wetlands contained more plant species than unsown wetlands (sown: 46–56; unsown: 40–42 species/wetland), contained more native wetland plant species (sown: 25–42; unsown: 18–20 species/wetland) and had higher plant diversity (total and native wetland plants; data reported as a diversity index). However, vegetation cover did not significantly differ between sown and unsown wetlands. This was true for cover of all vegetation (sown: 40–73%; unsown: 29–67%) and cover of native wetland species only (sown: 21–59%; unsown: 6–41%). After two years, 17 of the 21 sown herb species were found in at least two of five sown wetlands. Meanwhile, the most abundant species in both types of wetland was cattail Typha spp. (sown: 13% cover; unsown: 17% cover; see original paper for data on abundance of other species). Methods: In autumn 1989 or 1990, ten areas of agricultural land (<2.2 ha) were flooded by blocking or removing drainage channels. Five were also sown with a mix of 22 wetland plant species (21 herbs, 1 shrub). When each wetland was one or two years old, all plant species were recorded and vegetation cover was estimated in twenty-five 1-m² quadrats.

(Summarised by: Nigel Taylor)
Raise water level to restore/create freshwater marshes from other land uses

A replicated study in 1990–1992 of 11 wetlands created or restored on farmland in Wisconsin, USA (Reinartz & Warne 1993) reported that they had developed vegetation cover, mostly of wetland plants. On average, 3-year-old created wetlands contained 44 plant species with 85% total vegetation cover, and 23 native wetland plant species with 60% cover. The most abundant plant species were cattails Typha spp. (33% cover). Woody plants were present around the wetland margins. The overall plant community composition changed with wetland age (data reported as a graphical analysis; statistical significance of differences not assessed). Similarly, vegetation cover was generally higher in older wetlands, with 3-year-old wetlands having significantly greater vegetation cover than 1-year-old wetlands (total: 28%; native wetland: 6%). However, plant species richness and diversity did not significantly change with wetland age (see original paper for data). Methods: In autumn 1988 or 1989, eleven areas of agricultural land (<2.2 ha) were flooded by blocking or removing drainage channels. Vegetation was surveyed one year after flooding (1990, five wetlands), two years after (1991, eleven wetlands) or three years after (1992, six wetlands). Plant species and cover were recorded in twenty-five 1-m² quadrats/wetland, and a complete species list was made for each wetland.

(Summarised by: Nigel Taylor)