Marsh Organ Research

The invasive grass Phragmites australis subsp. australis (hereafter ‘Phragmites’) negatively affects marsh ecosystems by outcompeting native vegetation, reducing fish and waterfowl habitat, altering biogeochemical cycles, increasing fire risk, and reducing the aesthetic value. Further, widespread attempts to reduce Phragmites through physical and chemical removal techniques often fail to reduce its abundance and may harm native ecosystems more than leaving Phragmites unmanaged. Phragmites may also provide beneficial ecosystem services that increase coastal resiliency, including sediment accretion, soil stabilization. and carbon sequestration.  Thus, understanding whether the benefits of managing Phragmites outweigh its risk is critical to effective management. In today’s world of increasing sea level rise (SLR) and global change, this approach requires understanding of both the relative costs-benefits of Phragmites vs. its management and of Phragmites compared to the desired management outcome—restored native plant communities. Coastal North Carolina is well suited for investigating these tradeoffs, as increasing coastal resiliency and managing Phragmites, which often outcompetes diverse native Spartina alterniflora (hereafter ‘Spartina’), are both state-wide priorities. 

The objective of this research is to investigate how the performance of and ecosystem services provided by Phragmites vs. Spartina are affected by Phragmites management SLR and salinity. To this end, we ask:

1. Do SLR and increasing salinity differentially affect Phragmites vs. Spartina performance?

2. Does Phragmites provide more beneficial ecosystems services (i.e., carbon sequestration and accretion) than Spartina in the face of predicted global change (i.e., SLR and increasing salinity)?