Coral assemblages and physico-chemical characteristics of the Whitsunday Islands: evidence of recent community changes

Benthic communities were assessed and 22 environmental variables were monit ored at seven leeward localities (L1-L7) in the Whitsunday Islands, Queensl and, Australia. L1 was near the Proserpine and O'Connell river mouths and L 7 similar to 80 km north of the river mouths. Distinct physico-chemical and biological gradients were evident. Sparse scleractinian coral communities, dominated by faviids, Montipora spp. and encrusting Porites colonies, were present at L1, L2 and L3, whereas diverse reef-building communities, domin ated by Acropora spp., were more common at and beyond L4. The number of cor al recruits (age <6 months) did not differ significantly among localities, suggesting that coral recruitment was near random and that the environment shapes the adult community from those recruits. The study demonstrates stro ng negative relationships between chlorophyll a and the following: percenta ge coral cover, coral species richness and coral abundance. The reef-buildi ng capacities of the coral communities and the extent of Holocene reef deve lopment were inconsistent at L2 and L3, which is interpreted as a sign of a nthropogenic effects.