Looking Forward, Looking Back

In the world of managing systems that include both people and nature, the recognition of ecological regimes and the processes that mediate the shift among regimes requires new ways of thinking about management and governance. Last fall, colleagues working at the ARC Center of Excellence for Coral Reef Studies in Australia published a fascinating paper that demonstrates the forward and backward pathways of regime shifts. Bellwood et al. (2006) experimentally forced a regime shift from coral to algal dominance by removing herbivores from the system. They then observed the shift back to the coral state. Their surprising finding was that a fish that was not known as a herbivore was the primary driver in the restoration of the coral state. This demonstration of hysteresis, in which the pathway back is not the same as the one forward, was labeled “sleeping” functional diversity.