Vegetation productivity of planted and unplanted created riverine wetlands in years 15–17

Abstract

Wetland creation and restoration have been key factors in reducing net loss of wetland habitat in the United States. Creation and restoration techniques, such as introducing vegetation, are perceived to have a long-term effect on wetland structure and function over time. The goal of this study was to compare macrophyte structure and function between a planted and unplanted (naturally colonizing) wetland more than 14 years after the wetlands were created in 1994 at the Olentangy River Wetland Research Park in central Ohio, USA. Species richness, floristic quality, community diversity, and aboveground and belowground productivity were examined throughout the growing season for Years 15 through 17 of these wetlands.The planted wetland had higher floristic quality assessment index scores (planted 23.2–23.8; unplanted 19.9–20, p=0.001). Community diversity was similar between the two wetlands (CDI: planted 1.16–1.71; unplanted 1.03–1.45, p=0.388). Aboveground net primary productivity of emergent vegetation was higher in the unplanted wetland (796–866g dry weight m−2 yr−1) than in the planted wetland (673–712g dry weight m−2 yr−1) (p=0.006). While planting a riverine wetland may not be as important as planting isolated wetlands, this study did find some differences in structure and function in the planted and unplanted wetlands more than14 years after the wetlands were created. While planting riverine wetlands may aid in increased floristic quality of the wetland in the short term, these two wetland marshes appeared to be converging overall in structure and function during the 3 years of this study.