This project uses 35 years of data from Heron Island, the Great Barrier Reef, Australia, to investigate the effects of large, infrequent disturbances on the dynamics of corals and algae at a variety of sites (see map). Even though the sites are separated by no more than a few hundred meters, the effects of the large storms (the arrows in these graphs) differ markedly from site to site. Similarly, the sites differ markedly in the rate and degree of recovery after the storms: knowing the trends in one place does not necessarily give any information about the trends at nearby locations. Equally sobering, knowing the conditions during an interval of, say, five years does not tell much about what happens at a given location during longer intervals. Between storms, the interactions among corals depend strongly on the details of their spatial configurations, which in turn depend strongly on their density. Being able to localize the effects of the interactions on the growth of the colonies to particular segments along their borders makes it possible to construct hierarchies of the competitive relationships among these species. These hierarchies also differ from site to site. The rich diversity of this assemblage of species is a product of the their interactions, the disturbances, and their spatial variability.