Created wetlands support similar communities of low conservation value as established wetlands in Michigan

Wetlands created for the purpose of compensatory mitigation are among the few widely practiced examples of habitat creation, yet lack follow-up studies to determine if they meet desired conservation goals. We asked whether created wetlands achieve the same level of biodiversity and conservation value as established wetlands, and whether the aquatic communities of created wetlands become more similar to those of nearby established wetlands across space and time. We compared the plant, aquatic macroinvertebrate, fish, and herpetofauna assemblages of 10 wetlands created by the Michigan Department of Transportation, to 10 nearby established wetlands. Both created and established wetlands supported high proportions of generalist, non-native, or invasive species, and both achieved low to moderate assessment scores. We found no significant differences in biodiversity or conservation value between created and established sites, nor were there any distinct patterns of taxonomic composition between these two broad categories. Wetland age did not predict community similarity, yet geographic distance was a significant predictor when sites were within ~ 2 km of each other. These results suggest that created wetlands support similar biodiversity as established wetlands, though both types show clear indicators of anthropogenic degradation.