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

Abstract

Benthic communities were assessed and 22 environmental variables were monitored at seven leeward localities (L1ŒL7) in the Whitsunday Islands, Queensland, Australia. L1 was near the Proserpine and O’Connell river mouths and L7 ~80 km north of the river mouths. Distinct physico Œchemical 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, dominated by Acropora spp., were more common at and beyond L4. The number of coral 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 strong negative relationships between chlorophyll a and the following: percentage coral cover, coral species richness and coral abundance. The reef-building capacities of the coral communities and the extent of Holocene reef development were inconsistent at L2 and L3, which is interpreted as a sign of anthropogenic effects.