Alternative states on coral reefs: beyond coral–macroalgal phase shifts

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 376:295-306 (2009) - DOI: https://doi.org/10.3354/meps07815 REVIEW Alternative states on coral reefs: beyond coral–macroalgal phase shifts Albert V. Norström1,2,*, Magnus Nyström1,2, Jerker Lokrantz1,2, Carl Folke2,3 1Natural Resource Management, Department of Systems Ecology, Stockholm University, SE-106 91 Stockholm, Sweden 2Stockholm Resilience Centre, Stockholm University, SE-106 91 Stockholm, Sweden 3The Beijer Institute, The Royal Swedish Academy of Sciences, SE-104 05 Stockholm, Sweden *Email: albert@ecology.su.se ABSTRACT: Degradation of coral reefs is often associated with changes in community structure where macroalgae become the dominant benthic life form. These phase shifts can be difficult to reverse. The debate on coral reef phase shifts has not focused on reports of coral reefs becoming dominated by other life forms following disturbance. A review of the primary and grey literature indicates that reefs dominated by corallimorpharia, soft corals, sponges and sea urchins can enter an alternative state as a result of a phase shift. Shifts can be triggered by pulse disturbances that cause large-scale coral mortality, and may become stable as a result of positive feedback mechanisms. However, they may differ from the archetypical coral–macroalgae shift, depending on the factors driving the shift; whereas coral–macroalgae and coral–urchin shifts seem to be driven by loss of top-down control through overfishing, shifts to corallimorpharian, soft coral and sponge dominance seem more associated with changes in bottom-up dynamics. Understanding the differences and similarities in mechanisms that cause and maintain this variety of alternative states will aid management aimed at preventing and reversing phase shifts of coral reefs. KEY WORDS: Phase shifts · Coral reefs · Alternative states · Corallimorpharia · Soft coral · Sponge · Urchin barren Full text in pdf format PreviousNextCite this article as: Norström AV, Nyström M, Lokrantz J, Folke C (2009) Alternative states on coral reefs: beyond coral–macroalgal phase shifts. Mar Ecol Prog Ser 376:295-306. https://doi.org/10.3354/meps07815 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 376. Online publication date: February 11, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.