Salt marshes play a key role in the global carbon cycle and support a range of valuable ecosystem services. However, human activity has altered salt marshes through tidal flow restrictions which reduce tidal effect in salt marshes, leading to less saltwater but more nutrient-rich fresh water flushing. Finally, the restrictions alter original habitat and make way for freshwater wetland and invasive species.
In Massachusetts, salt marshes restoration has been conducted since decades ago. However, rare reports have undertaken to evaluate the restoration efficacy. Here, through a 10 y chronosequence experiment, we measured the CO2 and CH4 emissions in restored and natural salt marshes in 2015. We also compared the green house gases (GHGs) emissions across the chronsequence.
Results/Conclusions
By comparing sites restored over multiple years, we found that the GHGs emission were similar between restored and natural saltmarsh after 8 yrs removing of restriction. However, under unrestored and recently restored saltmarsh, the CH4 emission were greater than their corresponding natural saltmarsh. We also compared the sediment bulk density and vegetation biomass between them. Our results would be useful for restoration managers, or local residents as we provide estimated recovery time and insight to how extensively biogeochemical functions will be restored following remove of tidal restrictions.