Corals and phase shifts: Reply from Nyström, Folke & Moberg

Abstract

We welcome the comments made by Scully and Ostrander, which highlight that phase shifts can occur in coral areas that are not under immediate anthropogenic influence, and that they might be a natural ingredient in the dynamics of modern coral reefs. To understand such changes, we do indeed need to address the influence of natural disturbance regimes on coral reef communities, and learn more about the complex interactions between corals and macroalgae. Unfortunately, there might only be few, if any, pristine coral reefs left on which to study phase-shifts and natural disturbance regimes [Refs 1. Jackson J.B.C Reefs since Columbus. Coral Reefs. 1997; 16: 23-32 Crossref Scopus (415) Google Scholar , 2. Hatcher B.G Varieties of science for coral reef management. Coral Reefs. 1999; 18: 305-306 Crossref Scopus (8) Google Scholar and see Bryant, D. et al. (1998) Reefs at risk. A map-based indicator of potential threats to the world's coral reefs: http://www.wri.org/wri/indictrs/reefrisk.htm]. A major point in our review 3. Nyström M et al. Coral reef disturbance and resilience in a human-dominated environment. Trends Ecol. Evol. 2000; 15: 413-417 Abstract Full Text Full Text PDF PubMed Scopus (553) Google Scholar was that these shifts seem to have become more frequent and less reversible because of human impacts and that humans might also alter the magnitude, frequency and duration of disturbance regimes.