A comparison of dipterans from ten created and ten natural wetlands
This study compares densities of common larval dipterans collected from areas dominated byPontederia cordata in 10 natural and 10 created freshwater herbaceous wetlands in central Florida. At each wetland, 7 core samples were collected from each of 5 stations during summer 1993. In addition, stem densities, vegetation areal coverage, pH, dissolved oxygen, water temperature, water depth, conductivity, sediment quality, and leaf litter were measured at 3 locations near each of the 5 stations in each wetland. Of the 57 dipteran taxa collected, 20 occurred with sufficient abundance to justify statistical comparison. Despite a large sampling effort, there were no significant differences in densities of 20 commonly occurring taxa found in created and natural wetlands after considering the effect of multiple univariate tests. Comparison of environmental variables showed significant differences in stem densities for vegetation other thanP. cordata, pH, conductivity, and sediment quality. Canonical correspondence analysis, used to relate environmental and biological variables, suggests that pH, conductivity, and sediment quality are only weakly related to dipteran community structure. Despite differences in environmental conditions, there is no convincing evidence of differences in natural and created wetland dipteran communities.