Study

Plant diversity and species richness decreased and waterfowl and amphibian communities stayed the same as wetlands matured over 12 years in Wisconsin, USA

  • Published source details Nedland T.S., Wolf A. & Reed T. (2007) A reexamination of restored wetlands in Manitowoc County, Wisconsin. Wetlands, 27, 999-1015

Actions

This study is summarised as evidence for the following.

Action Category

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

Action Link
Marsh and Swamp Conservation

Restore wetland

Action Link
Amphibian Conservation
  1. Restore/create freshwater marshes or swamps (specific intervention unclear)

    A replicated study in 1992–2004 of 11 wetland restoration sites in Wisconsin, USA (Nedland et al. 2007) reported that they developed wetland-characteristic herbaceous vegetation, which increased in quality over time. Each site was surveyed 1–4 years and 13–16 years after restoration. Nine sites contained mostly emergent vegetation, but two contained mostly submerged vegetation. Between the two surveys, the proportion of wetland-characteristic plant species increased, from 54% to 81% of all species present. The plant species also became more characteristic of undisturbed local habitats, on average (data reported as a conservatism score and floristic quality index; both increased but only the former significantly). However, there were declines in total plant species richness (from 108 to 84 species across all wetlands, and from 29 to 20 species/15 m2) and plant diversity (reported as a diversity index). For data on the presence/absence of individual plant species, see original paper. Methods: In August 1992 and 2004, plant species and their cover were recorded in 1-m2 quadrats in each of 11 wetland restoration sites (each <1 ha; 15–30 quadrats/site/survey). A complete plant species list was also made for each wetland. Restoration interventions had been carried out between 1988 and 1991 (details not reported). The analysis was based on change within each wetland over time.

    (Summarised by: Nigel Taylor)

  2. Restore wetland

    A replicated study in 1992–2004 of 16 restored wetlands in Wisconsin, USA (Nedland, Wolf & Reed 2007) found that amphibian communities stayed the same as wetlands matured over 12 years. The six amphibian species and overall amphibian abundance did not change between 1992 and 2004 (13–14 calls/wetland). Overall wetland species and coefficients of conservation values increased over time (coefficient: 3.6 vs 3.9). Restoration occurred between 1988 and 1991. Amphibians were monitored at eight wetlands. Four amphibian call surveys were undertaken at each in April–July. Plants and birds were also monitored.

     

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