Biomass and above-ground productivity of salt-marsh plants in south-eastern Australia

Abstract

The above-ground biomass of three dominant salt-marsh vascular plants (Juncus kraussii, Sarcocornia quinquejlora and Sporobolus virginicus) was measured to assess both spatial and temporal variation and to provide baseline data. Additionally, the culm dynamics of the rush J. kraussii were measured so that aboveground productivity could be estimated.

No distinct seasonal patterns were detected in above-ground biomass in J. kraussii. Averaged over all sites and times, the above-ground biomass of J. kraussii was 1116 g dry weight m^-2. Culms are replaced annually, hence standing crop approximated annual above-ground productivity. Much of the dead aboveground biomass appears to accumulate in the upper marsh, as evidenced by the elevated nutrient and organic carbon content of the soil there relative to the sediment in the mangrove zone. Above-ground biomass of the decumbent perennial grass Sporobolus virginicus and the procumbent perennial chenopod Sarcocornia quinqueflora showed no consistent spatial or temporal trends. The above-ground standing crops of these species were about one-third that of J. kraussii.