Competition between corals and algal turfs along a gradient of terrestrialinfluence in the nearshore central Great Barrier Reef

Competition between benthic algae and corals is a key process in the commun ity ecology of reefs, especially during reef degradation. However, there ha ve been very few experimental tests for competition between corals and bent hic algae, despite widespread assumptions that algae are generally superior competitors, especially in eutrophic conditions. This study tested for com petition for space between the massive coral Porites lobata and algal filam entous turfs on three reefs along a cross-shelf gradient of terrestrial inf luence, by experimentally removing or damaging either corals or algae. The corals and algae were competing for space, but, significantly, the algae ap peared to have little effect on coral growth. In contrast, corals significa ntly inhibited algal growth, suggesting Porites was the competitive superio r. Importantly, coral growth was generally positive, even on the reef with the greatest terrestrial influence. Competitive outcomes did not support th e argument that algae are more successful competitors in more eutrophic con ditions.