ABSTRACT:

Coral reefs grow in ocean waters from the equator to over 30 degrees of latitude and the processes controlling assemblage structure and rates of recovery from disturbance are likely to vary dramatically over this range.. However, the population ecology of individual species remains poorly explored, particularly at large spatial scales. In this thesis, I will test for spatial variation in growth, reproduction and condition in populations of Acropora millepora at 8 sites in four regions separated by 9 degrees of latitude on the Great Barrier Reef: the Lizard Island groups, the Palms Island, the Whitsundays and the Keppels. In addition, I will explore how these processes respond to environmental variables using an innovative combination of biochemistry and molecular biology. Preliminary results indicate considerable spatial and seasonal variation in growth rates among these populations: colonies in the Keppel Islands (230 N) grew throughout the year and annualised growth (mean + one SE: 8.975 + 0.5166 cm) was 3-times that of colonies in the Whitsundays (200 N) (2.408 + 0.4738 cm) and Palm Islands (180 N) (2.334 + 0.8355 cm). In contrast, there was little spatial variation in fecundity: only Myle Islands in the Keppel had significantly greater per polyp fecundity. This suggests that fecundity is more constrained than growth. Also, the predicted trade off between growth and reproduction was not evident at Myle Island due to either greater productivity or lower annual light and thermal stress in this region.