Weak Relationships Between Environmental Factors and Invertebrate Communities in Constructed Wetlands

Growing awareness of essential wetland functions is providing support for wetland construction projects. Biomonitoring using invertebrates is a common way to evaluate project success, but relationships between wetland invertebrates and environmental factors are often weak. In recently constructed wetlands on Maryland’s Eastern Shore, we tested the hypothesis that focusing on predator and primary consumer invertebrate assemblages versus the entire community would elucidate stronger relationships with environmental factors. Despite variation in factors that are hypothesized to control wetland invertebrates (e.g., vegetation and tendency to dry), our results indicated weak relationships between environmental factors and the structure and composition of the entire community as well as predator and primary consumer assemblages separately. Examining the entire community and individual assemblages, however, showed that invertebrates were influenced by temporal factors. We propose that a complex interaction between wetland shape/size, local weather, and seasonal changes may have driven invertebrate community patterns among wetlands. Such interactions would complicate bioassessments of wetlands that differ in size, hydrology, and local weather conditions. Further study of specific factors controlling wetland invertebrates and developing new metrics that incorporate seasonal environmental change could improve biomonitoring results and thus management strategies aimed at enhancing wetland function.