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
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Decision support tools for managing coral reef systems at
local to regional scales
Jess Melbourne-ThomasGEF 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
Key challengesThe 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 pieces1. Local scale ecological model
herbivoressmall
piscivores
urchinslarge
piscivores
macroturf
spawning corals
brooding corals
macroalgae
grazed EACBenthos Consumers
Assembling the pieces2. Connectivity via larval transport
herbivoressmall
piscivores
urchinslarge
piscivores
macroturf
spawning corals
brooding corals
macroalgae
grazed EACBenthos Consumers
larval transport for corals, fish and urchins
Assembling the pieces3. Human impacts and disturbances affect local and regional scale processes
herbivoressmall
piscivores
urchinslarge
piscivores
macroturf
spawning corals
brooding corals
macroalgae
grazed EACBenthos Consumers
hurricanes
fishing
coastal development
Testing the frameworkThe 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 systemStable 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 systemStable trajectories in consumer dynamics over long time series
Testing the framework
piscivores
herbivores
urchins
timestep (years)
Testing the frameworkEmergent spatial variability driven by patterns of larval connectivity
1
2
3
4
5
subregion 1 2 3 4 5
subregion 1 2 3 4 5
Testing the frameworkEmergent spatial variability driven by patterns of larval connectivity
Regional variation in the ratio of herbivores : piscivores
Low fish recruitment to Chinchorro
1
2
3
4
5
1980 1990 2000 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 framework2. 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 framework2. 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 piscivores urchins
South China Sea
Sulu SeaKalayaan Islands
Demonstrating portabilityPhilippines / South China Sea (SCS) region
500km
1
5
2
3
4
1 2 3 4 5
Emergent variability
1
2
3
4
5
South China Sea
Timeline for the Philippines-SCS: 1960 – present
1980 1990
1998: 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]
1960 1970 2000 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
Reservesfish biomass (g/m2) 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
frequ
ency
of m
odel
out
com
es
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
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