Modelling and Decision Support Working Group Decision support

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

Key challenges 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 grazed EAC Consumers macroturf macroalgae herbivores small piscivores spawning corals brooding corals large piscivores urchins Benthos

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

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

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?

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 benthic dynamics over long time series macroturf coral macroalgae timestep (years)

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 piscivores herbivores urchins timestep (years)

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

Testing the framework Emergent spatial variability driven by patterns of larval connectivity 1 2 3 subregion 4 5 3 4 Regional variation in the ratio of herbivores : piscivores 5 Low fish recruitment to Chinchorro 1 2 3 subregion 4 5

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

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 = hurricane = bleaching/disease Mexico Belize Honduras

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 herbivores piscivores urchins Mexico Belize Honduras

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

Emergent variability 1 2 3 5 4 1 2 3 4 5

1 Timeline for the Philippines-SCS: 1960 – present 2006: Typhoon Cimaron [subregion 1] Typhoons Xansane and Durian [subregion 2], COTS outbreak [subregions 1, 2 & 4] 2004: Typhoon Nanmadol [subregion 1], COTS outbreak [subregion 3] 1999: Typhoon Dan [subregion 1] 2 South China Sea 3 1998: Bleaching event [entire region] 5 1995: Typhoon Angela [subregion 2] 1993: Typhoon Koryn [subregion 1] 4 1991: Mt. Pinatubo eruption [subregion 1] 1989: Typhoons Gordon and Angela [subregion 1] 1987: Typhoons Betty and Nina [subregion 2] 1983: Bleaching event [subregion 1] 1962: Typhoon Lucy [subregion 5] 1960 1970 1980 1990 2000 present 1986: muro-ami banned [entire region] 1990 s: advent of pa-aling and decline in dynamite fishing [entire region] 1965 – 1990: increase in destructive fishing [subregions 1 – 4] 1990 – present: decrease in destructive fishing 1960 – present: increasing fishing pressure [entire region] 1960 – present: increasing nutrient/sediment inputs from land clearing [subregions 1 – 4]

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

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

Dissemination

Dissemination Demonstrating the importance of managing water quality to build resilience

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

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

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

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