Human influence past and present - Relationship of nutrient and hydrologic conditions to urban wetland macrophyte distribution

Urban wetlands can provide valuable ecological services through filration and moderation of non-point source pollutants. They provide habitat for wildlife, green space, and recreational opportunities for nearby human populations. We investigated and isolated section of an urban wetland in the Cleveland metropolitan area to determine the overall quality of the vegetation and to evaluate the site for possible rehabilitation. We also researched the distribution of plant species in relation to existing hydrologic, soil, and nutrient conditions in order to identify possible impacts of historic or present human activities in the surrounding watershed. Vegetation composition and physical/chemical parameters were measured in 1.0 × 1.0 m2 plots along three transects. Canonical correspondence analysis (CCA) was used to directly correlate species distributions to nutrient concentrations, soil carbon content, and water depth. Our sample area was dominated by Typha angustifolia, Leersia oryzoides, and Sparganium eurycarpum. A few high quality species were present, but the overall macrophyte community was indicative of human disturbance. Historic information revealed a long history of disturbance at the site and continuing anthropogenic impact. Patchiness in nutrient and water depth gradients results from historic and current human impacts in the study area. Our results indicate any rehabilitation efforts of the site need to take into account past and current anthropogenic stressors. We recommend aggressive removal of invasive species and re-introduction of nutrient-tolerant native taxa to achieve successful rehabilitation at the site.