Reversing a regime shift (or not)

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Science  22 Dec 2017:
Vol. 358, Issue 6370, pp. 1552-1553
DOI: 10.1126/science.358.6370.1552-f

Herbivores are needed to keep the macroalga Sargassum from replacing corals.


Coral reefs worldwide face many challenges. One of these, brought on by declines in herbivore populations on reefs, is a tendency to shift from dominance by live corals to dominance by macroalgae. Loffler and Hoey, in a study of the leathery brown macroalga Sargassum on Australia's Great Barrier Reef, show how hard it is to reverse this regime shift. Physical removal of the Sargassum canopy, simulating the activity of storms, had a negligible effect, and even removal of the alga's “rooting” holdfasts was only a temporary setback to the Sargassum community. To improve the likelihood of restoring the coral community, physical removal needs to be accompanied by herbivore activity.

J. Ecol. 10.1111/1365-2745.12875 (2017).

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