MCR LTER: Coral Reef: Data to support manuscript: Experimental Support for Alternative Attractors on Coral Reefs

Ecological theory predicts that ecosystems with multiple basins of attraction can get
locked in an undesired state, which has profound ecological and management implications.
Despite their significance, alternative attractors have proven to be challenging to detect
and characterize in natural communities. On coral reefs, it has been hypothesized that
persistent coral-to-macroalgae ‘phase shifts’ that can result from overfishing of herbivores
and/or nutrient enrichment may reflect a regime shift to an alternate attractor, but to date
the evidence has been equivocal. Our field experiments in Moorea, French Polynesia,
revealed: (1) hysteresis in the herbivory - macroalgae relationship, creating the potential
for coral - macroalgae bistability at some levels of herbivory, and (2) that macroalgae were
an alternative attractor under prevailing conditions in the lagoon but not on the fore reef
where ambient herbivory fell outside the experimentally delineated region of hysteresis.
These findings help explain the different community responses to disturbances between lagoon
and fore reef habitats of Moorea over the past several decades, and reinforce the idea that
reversing an undesired shift on coral reefs can be difficult. Our experimental framework
represents a powerful diagnostic tool to probe for multiple attractors in ecological
systems, and as such, can inform management strategies needed to maintain critical ecosystem
functions in the face of escalating stresses. These data are associated with a manuscript currently in review: Schmitt, R. J.,
Holbrook, S. J., Davis, S. L., Brooks, A. J., Adam, T. C. Experimental support for
alternative attractors on coral reefs. The dataset includes data from two different
experimental tests of alternate attractors.