Decision support tools for managing coral reef systems at local to regional scales Jess Melbourne-Thomas GEF International Waters Conference October 2009 Modelling and Decision Support Working Group

Coral reef systems around the globe are vastly different (e.g. Indo-Pacific reefs versus Caribbean reefs, offshore atolls versus coastal systems) how can we develop a generic model structure that is capable of capturing these differences? Representing inter-reef connectivities is crucial to a regional-scale approach, but the type and quality of connectivity data available differs greatly between regions how can we design an approach to represent regional-scale connectivities that is flexible and portable? Key challenges

The dynamics of coral reefs and associated human systems are inextricably linked how can we couple biophysical and socioeconomic dynamics to capture diverse indicators of reef state? In addressing these issues, we need to ensure that the models we develop are robust what processes can we use for training and testing the models?

Addressing the challenges 1. Assembling the pieces - developing a generic model framework 2. Testing the framework - Meso-American Reef system 3. Demonstrating portability - Philippines/South China Sea region 4. Coupling biophysical and socioeconomic dynamics - the Mexican Caribbean

Assembling the pieces 1. Local scale ecological model herbivores small piscivores urchins large piscivores macroturf spawning corals brooding corals macroalgae grazed EAC Benthos Consumers

Assembling the pieces 2. Connectivity via larval transport herbivores small piscivores urchins large piscivores macroturf spawning corals brooding corals macroalgae grazed EAC Benthos Consumers larval transport for corals, fish and urchins

Assembling the pieces 3. Human impacts and disturbances affect local and regional scale processes herbivores small piscivores urchins large piscivores macroturf spawning corals brooding corals macroalgae grazed EAC Benthos Consumers hurricanes fishing coastal development

Testing the framework The Meso-American Reef system (MAR) 1. Can the model reproduce a healthy reef state in the absence of fishing and disturbance? 2. Does the model reproduce broad-scale dynamics over the past 30 years given a schedule of known disturbance events?

macroturf coral macroalgae timestep (years) 1. Can the model reproduce a healthy reef state in the absence of fishing and disturbance? Predicts community structure of a healthy reef system Stable trajectories in benthic dynamics over long time series Testing the framework

1. Can the model reproduce a healthy reef state in the absence of fishing and disturbance? Predicts community structure of a healthy reef system Stable trajectories in consumer dynamics over long time series Testing the framework piscivores herbivores urchins timestep (years)

Testing the framework Emergent spatial variability driven by patterns of larval connectivity

subregion subregion Testing the framework Emergent spatial variability driven by patterns of larval connectivity Regional variation in the ratio of herbivores : piscivores Low fish recruitment to Chinchorro

present 1980 – present: increasing fishing pressure (selective for large piscivores) [entire region] 1980 – present: increasing nutrient/sediment inputs from coastal development [entire region] 1986 – 1990: decline in hard coral cover due to white band disease and bleaching [subregion 4] 1983 – 1984: urchin mortality event [entire region] 1988: Hurricane Gilbert [subregion 1] 1998: Coral bleaching event [subregions 1, 2, 3 & 5], Hurricane Mitch [subregions 4 & 5] 2000: Hurricane Keith [subregion 4] 2001: Hurricane Iris [subregions 4 & 5] 2002: Hurricane Isidore [subregion 1] 2005: Hurricanes Wilma and Emily [subregion 1] 2007: Hurricane Dean [subregions 2 & 3] Timeline for the MAR: 1980 – present 2. Does the model reproduce broad-scale dynamics for the MAR over the past 30 years given a schedule of known disturbance events?

Testing the framework 2. Does the model reproduce broad-scale dynamics for the MAR over the past 30 years given a schedule of known disturbance events? Correspondence between model output and observations of reef condition coral algae Mexico Belize Honduras Mexico Belize Honduras = hurricane = bleaching/disease

Testing the framework 2. Does the model reproduce broad-scale dynamics for the MAR over the past 30 years given a schedule of known disturbance events? Correspondence between model output and observations of reef condition Mexico Belize Honduras Mexico Belize Honduras herbivores piscivoresurchins

South China Sea Sulu Sea Kalayaan Islands Demonstrating portability Philippines / South China Sea (SCS) region 500km

Emergent variability

South China Sea Timeline for the Philippines-SCS: 1960 – present : Bleaching event [entire region] 1986: muro-ami banned [entire region] 2006: Typhoon Cimaron [subregion 1] Typhoons Xansane and Durian [subregion 2], COTS outbreak [subregions 1, 2 & 4] 1991: Mt. Pinatubo eruption [subregion 1] present 1960 – present: increasing fishing pressure [entire region] 1960 – present: increasing nutrient/sediment inputs from land clearing [subregions 1 – 4] 1990s: advent of pa-aling and decline in dynamite fishing [entire region] 1962: Typhoon Lucy [subregion 5] 1987: Typhoons Betty and Nina [subregion 2] 1989: Typhoons Gordon and Angela [subregion 1] 1993: Typhoon Koryn [subregion 1] 1995: Typhoon Angela [subregion 2] 1999: Typhoon Dan [subregion 1] 2004: Typhoon Nanmadol [subregion 1], COTS outbreak [subregion 3] 1983: Bleaching event [subregion 1] 1965 – 1990: increase in destructive fishing [subregions 1 – 4] 1990 – present: decrease in destructive fishing

Scenarios for the Philippines: Marine Reserves fish biomass (g/m 2 ) herbivores, piscivores benthic cover (%) coral, algae (1) Reserve placement based on larval connectivity between subregions (2) Reserve placement based on larval connectivity within subregions (2) + additional management (reduced fishing pressure in northern subregions and gear restrictions) Best recovery of fish biomass and coral cover

Scenarios for the Philippines: Coral Bleaching H = Healthy NS = Nutrification + Sedimentation BL10 = Coral bleaching once every 10 years BL5 = Coral bleaching once every 5 years Synergistic effects of coral bleaching and nutrification + sedimentation on coral cover

Dissemination

Demonstrating the importance of managing water quality to build resilience Dissemination

Predicting distributions of potential reef futures under alternative management approaches indicator of reef state frequency of model outcomes

Socio-economic model (SimReef) Biophysical model lobsters Coupling biophysical and socioeconomic models for the Mexican Caribbean

Socio-economic model (SimReef) Biophysical model lobsters Coupling biophysical and socioeconomic models for the Mexican Caribbean

coral and algal cover (%) bankruptcies (# boats) and profits (1000 US$) fish and lobster catches (tonnes) Coupling biophysical and socioeconomic models for the Mexican Caribbean: Preliminary Validation