Wetlands are diverse environments whose vegetation provides numerous natural services including flood and erosion control and excess nutrient absorption; however conditions created by sea level rise and nutrient pollution could lead to possible wetland loss. To assess the responses of vegetation in these conditions in the Chesapeake Bay tidal wetlands, an observational study and a competition greenhouse study were conducted. An aboveground to belowground biomass relationship assessment was done along a salinity gradient within a subestuary of the Chesapeake Bay. The competition study focused on the relationship between a native and a non-native species in the aforementioned conditions. These studies revealed Phragmites australis had more biomass and lower rooting depths than the native Spartina cynosuroides under varying conditions of salinity, competition, and fertilization. Growth of S. cynosuroides may facilitate the growth of P. australis through salinity uptake and root aeration, which could have important impacts on wetland management practices.