TEMPORAL CHANGES IN THE ABUNDANCE OF SOME TROPICAL INTERTIDAL SEAGRASSES IN NORTH QUEENSLAND

Temporal patterns in plant cover and above and below-ground biomass we re determined for tropical intertidal seagrasses at three coastal seag rass meadows in the Townsville region of northern Australia. Methods i ncluding monitoring of permanent intact quadrats using photography and a modified point quadrat technique, and harvesting adjacent quadrats, were employed to sample seagrasses at three-monthly intervals for two years. Abundance of total seagrass and individual seagrass species fl uctuated seasonally by a factor of between two and four depending on t he species, with minimum abundance in the dry season (August to Septem ber) and subsequent recovery of seagrass during the wet season months (November to March). There was some variation in this pattern among bo th sites and years. Correlations between seagrass abundance and climat ic factors were examined via principal components analysis and multipl e regression. Seagrass standing crop was positively correlated with da ylength, temperature and rainfall events, However, the best model expl ained only 48% of the variation. Temporal changes in seagrass communit y composition appeared consistent with successional theory.