A comparison of natural and created depressional wetlands in central Oklahoma using metrics from indices of biological integrity

Abstract

Created wetlands and water bodies that have wetland characteristics (old farm ponds) appear to provide many of the habitat attributes of natural systems. To compare the biological and physical characteristics of natural and created wetlands, we evaluated water chemistry and a suite of metrics associated with the plant, macroinvertebrate, and avian assemblages at 12 natural and six created systems in central Oklahoma. The natural wetlands had significantly shallower depths and higher turbidity levels than the created wetlands. Of 43 metrics across the three biotic assemblages, seven were significantly different between the two wetland types. The proportions of hemipteran insects from the family Corixidae and insectivorous bird species were both greater in natural than created wetlands. The proportion of perennial plant species, the proportion of invertebrates in the shredder feeding guild, the number of Ephemeroptera, Trichoptera, Sphaeridae, and dragonfly (ETSD) taxa, the proportion of individuals in the dominant bird taxa, and the proportion of avian edge species were all greater in created wetlands than in natural wetlands. The community similarity (based on Jaccard’s similarity index) in the two wetland types was 38% for plants, 56% for macroinvertebrates, and 65% for birds. For some individual metrics, assemblage members had similar attributes (e.g., proportion of omnivorous taxa) although the specific taxa often differed between natural and created wetlands. These differences may influence the performance of certain assessment methods when they are applied to created wetlands.