We studied the natural revegetation of six wetlands created in 1988 and six wetlands created in 1989 in Ozaukee County, Wisconsin. By describing the flora and vegetation of these two sets of wetlands we could compare the development of plant communities in one- and two-year old wetlands. Of the 119 species found in the 12 wetlands, 64% were native, 62% were wetland plants, and 65% were perennials. More species were found in two-year old than in one-year old wetlands. There was also a strong correlation between wetland size and the number of species present during the first year after construction. Two-year old wetlands had a higher percentage of native plants and of wetland plants and a much higher total plant cover than did one-year old wetlands. However, while species richness increased, evenness declined from one- to two-year old wetlands so overall species diversity did not change. Evenness declined because of a dramatic increase in the dominance of two-year old wetlands by cattails (Typha spp.). Our results lead us to predict that the wetlands will become surrounded by willow shrub "rings", and they may develop into near monocultures of cattail in the future. Continuance of the study will compare naturally colonized wetlands with wetlands seeded with native wetland species.
Reinartz, J.A. and E.L. Warne. 1990. Development of vegetation in wetlands restored on Ozaukee County Conservation Reserve Program Lands. Field Station Bulletin 23(2): 18-34.