Assessing methods for nursery production of Georgia native smooth cordgrass (Spartina alterniflora)

REU Fellow: Anna He, Duke University

Mentor: Dr. Heather Joesting

Georgia has some of the most extensive salt marshes in the United States. Coastal salt marshes provide critical ecosystem services such as filtering water and preventing coastal erosion. Smooth cordgrass (Spartina alterniflora) is the dominant salt marsh plant species, contributing to the salt marsh ecosystem by providing high primary productivity. However, threats like climate change are degrading salt marsh habitat, necessitating its restoration. Using locally grown sources of Spartina alterniflora in restoration projects is recommended to increase the likelihood of restoration success, but Georgia currently has no local source. Our study examined if Spartina alterniflora can be produced in a constructed wetland designed to remediate aquaculture effluent. We hypothesized that S. alterniflora grown in the constructed wetland would have equal or greater plant growth and productivity compared to those grown using traditional nursery practices. A total of 160 S. alterniflora rhizomes and seedlings were randomly assigned to a constructed wetland or traditional nursery treatment. Stem height, number of ramets, and chlorophyll content were measured weekly for four weeks. Data were analyzed with principal component analysis (PCA) to explore differences between treatments. The PCA plot did not reveal significant separation of data between the wetland and traditional treatments; however, some plants in the wetland had notably higher percent change in height values. Between treatments, there was a significant difference for PC two and PC three, but not PC one. These preliminary results suggest that S. alterniflora plants in the wetland treatment may have greater average growth rate, percent change in height, and possibly number of ramets, but not chlorophyll content. Therefore, nursery production of Spartina alterniflora is possible and perhaps enhanced in a constructed wetland compared to a traditional nursery. However, more time and data collection are needed to fully assess the effect of treatments on S. alterniflora growth and productivity.