| Macroinvertebrate communities of 8 natural wetlands and 11 constructed wetlands of varying ages were sampled quarterly for 1 year. Shifts in macroinvertebrate assemblages occurring during constructed wetland development were estimated using data from constructed wetlands of varying ages. Macroinvertebrate assemblages of natural and constructed wetlands were compared and the efficacy of using macroinvertebrates as indicators of constructed and natural wetland structure and function was evaluated.; Natural wetlands were more similar to older constructed wetlands ({dollar}>{dollar}3 years old) than to newly constructed wetlands, providing evidence of directional changes over time. Parameters showing this pattern included macroinvertebrate community structure (Morisita's Similarity Index), structure of feeding guild, community macroindicators (total organism abundance, taxa richness, and diversity), degree of siltation, and vegetation density. Based on a confidence interval analysis, macroinvertebrate abundance, species richness, and diversity constructed wetlands did not attain stability relative to natural wetlands within the age range studied (8 years).; Natural wetlands supported a higher number of semi-terrestrial invertebrate species than constructed wetlands probably because some of the natural wetlands studied went through a dry down phase during the dry season. I conclude that macroinvertebrates may provide a useful indication of hydrological function.; Sediments in constructed wetlands with gently sloping banks ({dollar}<{dollar}1.5 percent) were lower in silt content than constructed wetlands with steeper slopes. Sediments of older constructed wetlands tended to be lower in silt content than sediments of newly constructed wetlands, but results were not significant (p = 0.0601, R-square = 0.76).; Siltation may be reduced over time as constructed wetland banks are vegetated and become more stabilized. In spite of constraints imposed by high variability of macroinvertebrate populations, I conclude that a reduced sampling effort directed toward the collection of key subsets of the macroinvertebrate community can be sufficient to detect the effects of major influential factors (hydrology, vegetation, water quality). Even when the sampling effort is limited, semi-terrestrial dipteran species and gastropods may be particularly useful indicators of wetland function (hydrology and energy flow, respectively). |
