Aquatic angiosperms in coastal saline lagoons of New South Wales. IV. Long-term changes

The area occupied by aquatic angiosperms and the biomass of Zostera capricorni have been documented for southern Lake Macquarie and the Tuggerah Lake from 1980 to 1985. The area of seagrasses in Lake Macquarie ranged from 4.81 to 6.75 km2, and the total biomass of Zostera from 543 to 1099 tonnes. Winter biomass was significantly greater than summer biomass. In the Tuggerah Lakes the area was 13.13-19.11 km2 and total biomass of Zostera 840-1888 tonnes. Differences between years were not significant because of the wide variation shown in both parameters. The data show no time-related trends or predictable changes. When vegetation survey is to function as baseline data this inherent viability in seagrass populations must be recognized.