Evaluating the ecological potential of constructed wetlands: A case study of the Brighton treatment wetland

Constructed wetlands for municipal wastewater treatment fulfill habitat needs of wildlife. This study is the first attempt to characterize the macroinvertebrate community in an Ontario treatment wetland. It consists of a baseline survey of benthic fauna from a tertiary treatment wetland in Brighton, Canada. Macroinvertebrate community indicators including diversity, abundance and functional feeding groups were compared between (a) treatment wetland cells with and without emergent vegetation and (b) the treatment wetland and three natural reference wetlands. Macroinvertebrate data were collected by kick and sweep sampling and Hester Dendy samplers. Environmental parameters were compared with macroinvertebrate findings. Non-metric multi-dimensional scaling and permutational analysis of variance were used to explore separations of both environmental variables and macroinvertebrate communities. The higher diversity of macroinvertebrates in the treatment wetland cell with emergent vegetation contrasted with the open water cell's abundant but less diverse community. Natural wetlands had more than twice the stem density as treatment wetlands and at least twice the number of taxa. Shallow water depths, more dissolved oxygen, and lower ammonia and conductivity levels contributed to the higher ecological potential of natural wetlands. Aeration, emergent plant harvesting and hydrologic alterations are explored as methods to help raise the ecological potential of treatment wetlands.; Keywords. Hester Dendy, macroinvertebrate, NMDS, treatment wetland, hemi-marsh, ecological potential, PERMANOVA.