Data for: Drainage impacts on the productivity of wetland species Spartina alterniflora and Salicornia pacifica

Coastal wetlands display ecohydrological zonation such that vertical
differences of plant zones are driven by varying groundwater levels over
tidal cycles. It is unclear how variable levels of tidal drainage directly
impact biotic and abiotic factors in coastal wetland ecosystems. To
determine the impacts of drainage levels, simulated tides in mesocosms
with varying degrees of drainage were created with Spartina alterniflora,
the salt marsh coastal ecosystem dominant species on the United
States Atlantic Coast, and Salicornia pacifica, the Pacific Coast
dominant. We measured biomass production and photosynthesis as indicators
of plant health, and we also measured soil and porewater characteristics
to help interpret patterns of productivity. These measures included above
and belowground biomass, porewater pH, salinity,
ammonium concentration, sulfide concentration, soil redox
potential, net ecosystem exchange, photosynthesis rate,
respiration rate, and methane flux. We found the greatest plant production
in soils with intermediate drainage levels, with production
values that were 13.7% higher for S. alterniflora and 57.7%
higher for S. pacifica in the intermediate flooding levels than found
in more inundated and more drained conditions. Understanding how
drainage impacts plant species is important for predicting
wetland resilience to sea level rise, as increasing water levels
alter ecohydrological zonation.