Sea level rise (SLR), while detrimental to many coastal wetland systems, may play a role in improving the health and habitat of other coastal wetland systems. Due to human alteration, some wetlands have transitioned from brackish to largely freshwater systems. This transition has been injurious to native plant species that depend on specific salinity levels to flourish, and has given a competitive advantage to invasive plant species such as Urochloa mutica. In this study, we aimed to determine the relationship between salinity and relative growth rates of invasive and native wetland vegetation.
Existing vegetation was removed in study plots over three salinity levels: freshwater (0-8ppt), brackish (8-15ppt), and high salinity (15-35ppt). Height, species, and water quality metrics such as salinity and dissolved oxygen were then collected every two weeks over six months. In low-salinity plots, growth of invasive species was more rapid than native species. In the mid- and high-salinity plots, native sedges and Batis maritima had the highest growth rates. These results will be used, together with SLR projection models, to project native and invasive wetland plant distribution under likely scenarios.