Longitudinal study reveals twofold interannual variation in Spartina alterniflora aboveground productivity, indicating sea level and rainfall regulate growth through sediment salinity.
Key Points
To document and explain interannual variability in aboveground primary productivity and stand characteristics of the salt marsh grass Spartina alterniflora.
Applied a non-destructive census method and modeled stem-age-dependent leaf turnover to track monthly Spartina alterniflora dynamics for >5 years at North Inlet, South Carolina.
Used numerical simulations to assess the error sensitivity of traditional destructive harvest techniques caused by spatial variability.
Monitored monthly growth rates, stem densities, and biomass densities across two marshes situated at mean high tide elevation over 3 years.
Aboveground productivity was 2.3 times greater than positive increments in standing biomass density, with stem turnover contributing 33% and leaf turnover contributing 23% to total production.
Annual aboveground production exhibited twofold interannual variation over 5 years, correlating positively with mean sea level and rainfall via their influence on sediment salinity.
Two marshes maintained equivalent aboveground productivity and biomass densities over 3 years despite a persistent twofold difference in stem density, demonstrating distinct photosynthate allocation strategies.