Water Resources Research Act Program

Details for Project ID 2015MS202B

Influence of wetland plant community types on water quality improvement in natural and restored wetlands of the Mississippi Delta

Institute: Mississippi
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-28
Total Federal Funds: $21,282 Total Non-Federal Funds: $42,577

Principal Investigators: Gary Ervin

Abstract: Restoration of former agricultural land to wetlands, funded largely by government mechanisms such as the Wetlands Reserve Program (WRP) and Conservation Reserve Program (CRP) typically has focused on restoring functions such as water quality improvement and the re-establishment of former wetland habitat for wildlife. Existing literature is inconclusive as to the long-term success of these projects, but research often shows a sizable fraction of restored wetlands to exhibit substantially lower ecological functionality than nearby natural wetlands. This project seeks to understand interactions between wetland function and wetland vegetation within the Mississippi portion of the Mississippi Alluvial Valley (MAV; simply referred to as the Mississippi Delta, or “Delta,” hereafter). Increasing allocation of land and money to conservation easements, along with an ever-increasing demand for quality agricultural land, make optimization of effectiveness and efficiency in land management decisions more important than ever. Unfortunately, little to no long term monitoring has been conducted on many wetland restoration sites, leaving the ultimate outcome of restoration efforts unknown. A better understanding of the influence of factors influencing critical wetland functions, such as nutrient and sediment abatement, will permit more effective targeting of limited resources towards restoration of sites having characteristics most conducive to restoring desired wetland function. During the summer of 2014, we assessed vegetation, land use, soils, and water quality in and around 24 restored and 6 natural wetlands across a gradient of human land use in the Delta. Results from that work revealed differences in soils and surrounding land use of natural vs. restored wetlands but showed few differences attributable solely to a priori classification of wetlands based on agricultural land use in the surrounding watershed. We also found that there is a great deal of variation in plant species among our study sites, and that types of plant species present vary between natural and restored wetlands, as well as among wetlands surrounded by different levels of land use intensity. In an effort to quantify the specific linkages between wetland plants and water quality, we will assess vegetation and water quality improvement (N, P, and sediment reductions, in particular) in the same set of 30 wetlands. This research will examine interactions among water quality parameters and plant species to determine which plant species assemblages appear to most strongly influence nutrient and sediment abatement. The data gathered in the proposed project will improve our understanding of interrelationships between water quality improvement and particular plant species assemblages encountered in Delta wetlands. The expectation is that this information can be incorporated into the design of future restorations such that they can yield the greatest improvements in water quality while also providing other benefits, such as wildlife habitat, for the Mississippi Delta.