title: Predicting climate-driven regime shifts versus rebound potential in coral reefs.
abstract: Climate-induced coral bleaching is among the greatest current threats to coral reefs, causing widespread loss of live coral cover. Conditions under which reefs bounce back from bleaching events or shift from coral to algal dominance are unknown, making it difficult to predict and plan for differing reef responses under climate change. Here we document and predict long-term reef responses to a major climate-induced coral bleaching event that caused unprecedented region-wide mortality of Indo-Pacific corals. Following loss of >90% live coral cover, 12 of 21 reefs recovered towards pre-disturbance live coral states, while nine reefs underwent regime shifts to fleshy macroalgae. Functional diversity of associated reef fish communities shifted substantially following bleaching, returning towards pre-disturbance structure on recovering reefs, while becoming progressively altered on regime shifting reefs. We identified threshold values for a range of factors that accurately predicted ecosystem response to the bleaching event. Recovery was favoured when reefs were structurally complex and in deeper water, when density of juvenile corals and herbivorous fishes was relatively high and when nutrient loads were low. Whether reefs were inside no-take marine reserves had no bearing on ecosystem trajectory. Although conditions governing regime shift or recovery dynamics were diverse, pre-disturbance quantification of simple factors such as structural complexity and water depth accurately predicted ecosystem trajectories. These findings foreshadow the likely divergent but predictable outcomes for reef ecosystems in response to climate change, thus guiding improved management and adaptation.
authors.affiliation: Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811 Australia.
authors.forename: Nicholas A J
authors.initials: NA
authors.lastname: Graham
authors.affiliation: 1] Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft NR33 OHT, UK [2] School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Jennings
authors.affiliation: 1] Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811 Australia [2] Australian Institute of Marine Science, PMB 3 Townsville MC, Townsville, Queensland 4810, Australia.
authors.forename: M Aaron
authors.initials: MA
authors.lastname: MacNeil
authors.affiliation: 1] Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811 Australia [2] ECOSYM, UMR CNRS-UM2 5119, Université Montpellier 2, 34095 Montpellier Cedex, France.
authors.forename: David
authors.initials: D
authors.lastname: Mouillot
authors.affiliation: 1] Department of Parks and Wildlife, Kensington, Perth, Western Australia 6151, Australia [2] School of Plant Biology, Oceans Institute, University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Shaun K
authors.initials: SK
authors.lastname: Wilson
mesh_terms: D000064:Acclimatization; D000818:Animals; D037421:Anthozoa / Q000254:growth & development* / Q000502:physiology*; D044822:Biodiversity; D057231:Climate Change; D057894:Coral Reefs; D017753:Ecosystem; D005399:Fishes / Q000502:physiology; D019156:Indian Ocean; D010140:Pacific Ocean; D011157:Population Dynamics; D012623:Seawater / Q000032:analysis; D012624:Seaweed / Q000502:physiology; D012750:Seychelles; D013559:Symbiosis; D014329:Tropical Climate