YEAR-TO-YEAR VARIATION IN PEAK ABOVE-GROUND BIOMASS OF 6 SALT-MARSH ANGIOSPERM COMMUNITIES AS RELATED TO RAINFALL DEFICIT AND INUNDATION FREQUENCY

Peak above-ground biomass of six annually mown salt-marsh angiosperm communities was measured over a 13-year period. Top soil salinity and soil moisture content in the six communities were measured during two dry years. Over the 13-year period the communities showed a synchronous pattern in peak biomass. Year-to-year variation in this biomass could be explained by the rainfall deficit during the growing season, while inundation frequency did not contribute to the regression model. Soil salinity and soil moisture content were significantly correlated with the rainfall deficit over a 2-year study period. Climatically induced year-to-year variation in soil conditions was held responsible for the observed year-to-year variation in peak above-ground biomass. © 1990.