Responses of tidal marsh macrophytes to salinity pulses as a result of sea level rise and drought

Due to reduced river discharge and sea level rise, tidal freshwater marshes will experience periodic to long-term higher salinities. Long-term saline water intrusion will trigger brackish species immigration into freshwater marshes, and eventually lead to a shift in community structure. However, we lack the ability to predict detailed vegetation responses. We used both field and mesocosm experiments to simulate the effects of salinity presses and pulses on the growth of three common freshwater plant species on the Altamaha River, GA. We found Smartweed was the most sensitive to high salinities both in the field and in mesocosm. Although long duration of saline water negatively affected production of all three species, the responses to salinity pulses varied among species.