Coral Reef EcosystemsCoral Reef Ecosystems
Ecology and Environmental Ecology and Environmental ManagementManagement
Lecture contentLecture content Coral reef ecologyCoral reef ecology
– How they are How they are formedformed
– Physical Physical EnvironmentEnvironment
– Diversity patternsDiversity patterns– Threats to coral Threats to coral
reefsreefs– FisheriesFisheries
Coral reef Coral reef managementmanagement– Assessing damageAssessing damage– Management for Management for
ecology and ecology and economicseconomics
– DiversificationDiversification– TourismTourism
Introduction to coral reefsIntroduction to coral reefs
What is a “coral reef”What is a “coral reef” Biological (“coral community”)Biological (“coral community”)
– Organic, BiogenicOrganic, Biogenic– Coral and Algal communitiesCoral and Algal communities– Mostly “hermatypic” corals, algae, and other Mostly “hermatypic” corals, algae, and other
sessile animalssessile animals Geological features (“reef”)Geological features (“reef”)
– CarbonateCarbonate– In situIn situ buildup buildup– Topographic reliefTopographic relief– Wave resistantWave resistant– Cemented, consolidatedCemented, consolidated
CoralsCorals Phylum Phylum
AnthazoaAnthazoa Class CnidariaClass Cnidaria Hermatypic Hermatypic
(hard) corals (hard) corals contain contain symbiotic symbiotic algaealgae
Up to 500 spp. Up to 500 spp. at some sitesat some sites
Rosen 1981
Building the reefBuilding the reefCaCo3 addition - CaCo3 loss = Accumulation
Biogenic Biogenic productionproduction
Sediment Sediment ImportImport
CementationCementation
Biological Biological erosionerosion
Mechanical Mechanical erosionerosion
Sediment Sediment export, export, dissolutiondissolution
Reef Reef GrowthGrowth
Kleypas et al 2001
Types of reefTypes of reef Fringing, Barrier, Atoll, DrownedFringing, Barrier, Atoll, Drowned
Environmental Environmental requirementsrequirements
Physical environmentPhysical environment– Temperature of 25-31Temperature of 25-31ooC (limited C (limited
Northwards by the 18Northwards by the 18ooC minimum C minimum isotherm)isotherm)
– Salinity of 34-37 pptSalinity of 34-37 ppt– Light levelLight level
Predominantly in top 30 m of waterPredominantly in top 30 m of water Biological environmentBiological environment
– Oligotrophic, highly stratified water Oligotrophic, highly stratified water columncolumn
Coral reef distributionCoral reef distribution
Coral diversity patternsCoral diversity patterns
MapsMaps For the lecture I used maps from a variety of locations, often more for For the lecture I used maps from a variety of locations, often more for
clarity than scientific detail. I would recommend the maps from the clarity than scientific detail. I would recommend the maps from the World Conservation Monitoring Centre (www.wcmc.org.uk) which I World Conservation Monitoring Centre (www.wcmc.org.uk) which I would tend to value as reliable.would tend to value as reliable.
The main point being that the high population densities in many The main point being that the high population densities in many coastal areas which contain high coral reef species richness represent coastal areas which contain high coral reef species richness represent a serious threat.a serious threat.
Fish communityFish community Mainly Perciform teleostsMainly Perciform teleosts 2 faunas, Diurnal and Nocturnal2 faunas, Diurnal and Nocturnal Often territorial/site attachedOften territorial/site attached Intraspecific interactions (pair bonding Intraspecific interactions (pair bonding
and harems) and interspecific and harems) and interspecific mutualism (e.g. cleaning stations)mutualism (e.g. cleaning stations)
Mostly planktonic larvaeMostly planktonic larvae Estimated 4500 spp, 25% of marine Estimated 4500 spp, 25% of marine
totaltotal ~10% of world fishery landings~10% of world fishery landings
Fishery speciesFishery species Often large, high-value fishOften large, high-value fish
Fish distribution patternsFish distribution patterns
World population World population distributiondistribution
And if that wasn’t bad And if that wasn’t bad enough…..enough…..
Threats to coral reef Threats to coral reef systemssystems
OverpopulatioOverpopulationn
Unsustainable Unsustainable fisheriesfisheries
Coastal Coastal developmentdevelopment
Global climate Global climate changechange
Coral reef fisheriesCoral reef fisheries Essential to survival of manyEssential to survival of many Managed sustainably for generations Managed sustainably for generations Diverse ecosystemDiverse ecosystem
– Multispecies fisheriesMultispecies fisheries– Interspecies interactions may invalidate Interspecies interactions may invalidate
modelsmodels– Collection of sufficient data for all species Collection of sufficient data for all species
may not be practicablemay not be practicable– Reduction of fishing effort to sustain all fish Reduction of fishing effort to sustain all fish
species wastes the productivity of most species wastes the productivity of most stocksstocks
Non-selective and Non-selective and destructive fishing methodsdestructive fishing methods Subsistence fishing occurs regardless Subsistence fishing occurs regardless
of effort requiredof effort required Muro Ami, Dynamite (Blast), and Muro Ami, Dynamite (Blast), and
cyanide fishingcyanide fishing TrawlingTrawling Trapping and linesTrapping and lines
– Ghost fishingGhost fishing Total fishing mortality often not Total fishing mortality often not
knownknown
Malthusian overfishingMalthusian overfishing ““...occurs when poor fishermen, ...occurs when poor fishermen,
faced with declining catches and faced with declining catches and lacking any alternative initiate lacking any alternative initiate wholesale resource destruction in wholesale resource destruction in order to maintain their incomes.order to maintain their incomes.
This may involve in order of This may involve in order of seriousness, and generally in seriousness, and generally in temporal sequence...temporal sequence...
1) Use of gears and mesh sizes not 1) Use of gears and mesh sizes not sanctioned by governmentsanctioned by government
2) Use of gears and mesh sizes not 2) Use of gears and mesh sizes not sanctioned within the fisherfolk sanctioned within the fisherfolk community…community…
3) Use of gears that destroy the resource 3) Use of gears that destroy the resource basebase
4) Use of gears such as dynamite or sodium 4) Use of gears such as dynamite or sodium cyanide that do all of the above and even cyanide that do all of the above and even endanger the fisherfolks themselves”endanger the fisherfolks themselves”
McManus 1997
Ecosystem effects of Ecosystem effects of fisheriesfisheries
Removal of predatorsRemoval of predators Removal of algal grazersRemoval of algal grazers Change in dominanceChange in dominance
– Californian Sea OttersCalifornian Sea Otters– UrchinsUrchins– Crown of Thorns starfish “COTS” Crown of Thorns starfish “COTS”
((Acanthaster planciAcanthaster planci)) Changes in size frequency of animalsChanges in size frequency of animals
Crown of Thorns StarfishCrown of Thorns Starfish
Crown of ThornsCrown of Thorns Eats coral by everting gutEats coral by everting gut Aggregations can remove 95% of coral Aggregations can remove 95% of coral
covercover May result in collapse of remaining May result in collapse of remaining
skeletonskeleton Pheromone controlled aggregated Pheromone controlled aggregated
spawningspawning Recovery takes at least 12 yearsRecovery takes at least 12 years Caused by loss of predators?Caused by loss of predators? Increased larval survival due to pollution? Increased larval survival due to pollution?
Terrestrial impactsTerrestrial impacts PollutionPollution
– SewageSewage– AgricultureAgriculture– AquacultureAquaculture– RubbishRubbish
SedimentationSedimentation EutrophicationEutrophication
Construction on Construction on reef flatsreef flats
Coral miningCoral mining Mangrove Mangrove
destructiondestruction
Climate changeClimate change Potential impacts on coral communitiesPotential impacts on coral communities
– Changes in water temperatureChanges in water temperature– Increases in COIncreases in CO22 concentration concentration– Changes in solar irradiation (if cloud cover Changes in solar irradiation (if cloud cover
changes)changes)– Sea level rises leading to drowning of reefsSea level rises leading to drowning of reefs– Changes in surface run-off (sedimentation)Changes in surface run-off (sedimentation)– Changes in land-use patterns leading to Changes in land-use patterns leading to
increased reef exploitationincreased reef exploitation
Kleypas et al 2001
Coral Coral bleachingbleaching
Loss of Loss of symbiotic algaesymbiotic algae
May cause May cause death of animaldeath of animal
A symptom of A symptom of climate climate change?change?
Coral BleachingCoral Bleaching First described in 1984First described in 1984 Multiple re-occurrences at same sitesMultiple re-occurrences at same sites New sites impacted during 1990sNew sites impacted during 1990s Many known triggersMany known triggers
– Temperature (especially increases)Temperature (especially increases)– Solar radiation (especially UV)Solar radiation (especially UV)– Combination of UV and temperatureCombination of UV and temperature– Reduced salinityReduced salinity– InfectionsInfections
Effects of bleachingEffects of bleaching Loss of symbiontic algae (Zooxanthellae) Loss of symbiontic algae (Zooxanthellae)
algae by:algae by:– Degradation Degradation In situIn situ– Loss of algae by exocytosisLoss of algae by exocytosis– Expulsion of intact endodermal cells containing Expulsion of intact endodermal cells containing
algaealgae Resulting impactsResulting impacts
– Vary between species, and even parts of the same Vary between species, and even parts of the same colonycolony
– Loss of sensitive species (especially Loss of sensitive species (especially AcroporaAcropora spp.) spp.)– Recovery slow and highly variable between sitesRecovery slow and highly variable between sites
The ProblemsThe Problems A large (and growing) number of A large (and growing) number of
people are dependent on coral reefspeople are dependent on coral reefs Management of a multispecies fishery Management of a multispecies fishery
is extremely complex, and often failsis extremely complex, and often fails Terrestrial development may destroy Terrestrial development may destroy
coastal reef systemscoastal reef systems Global climate change may exert new Global climate change may exert new
pressurespressures
Coral reef managementCoral reef management
Management IssuesManagement Issues BiologicalBiological
– What does the resource consist of?What does the resource consist of?– What state is it in?What state is it in?– Is there overfishing?Is there overfishing?– Is there habitat destruction?Is there habitat destruction?
Socio-ecomomicSocio-ecomomic– Levels of resource exploitationLevels of resource exploitation– More sustainable ways of exploiting the More sustainable ways of exploiting the
resourceresource– Alternatives to coral reef Alternatives to coral reef
exploitation/damageexploitation/damage
Monitoring coral reefsMonitoring coral reefs What sites and parameters to What sites and parameters to
monitor?monitor? FishFish MacroinvertebratesMacroinvertebrates Water qualityWater quality Benthic habitat qualityBenthic habitat quality Coral healthCoral health
SourcesSources Australian Institute for Marine Science (AIMS) website Australian Institute for Marine Science (AIMS) website
contains all their standard techniques. From a contains all their standard techniques. From a comparability point of view it is extremely helpful to use comparability point of view it is extremely helpful to use common techniques.common techniques.
The AIMS site and their manual (English et al, 1997) The AIMS site and their manual (English et al, 1997) even explains how to store the data in a database and even explains how to store the data in a database and manage it. Essential reading if you can get hold of it.manage it. Essential reading if you can get hold of it.
The use of volunteers for some types of coral reef The use of volunteers for some types of coral reef survey work is very common and slightly controversial. survey work is very common and slightly controversial. Common sense will be necessary in determining what Common sense will be necessary in determining what techniques a volunteer can apply - in particular for techniques a volunteer can apply - in particular for qualitative judgements about reef “quality” and levels qualitative judgements about reef “quality” and levels of impact.of impact.
Large-scale studiesLarge-scale studies Rapid Ecological Rapid Ecological
AssessmentAssessment– ““Manta tows”Manta tows”– Estimates of % cover Estimates of % cover
(live and dead coral)(live and dead coral)– Abundance of highly Abundance of highly
visible speciesvisible species– Human impactsHuman impacts
Mapping and aerial Mapping and aerial photographyphotography
Monitoring fishMonitoring fish Visual censusVisual census
– TransectsTransects– Point countsPoint counts– Random searchingRandom searching– Often allow biomass Often allow biomass
estimatesestimates Fisheries monitoringFisheries monitoring
Monitoring the benthosMonitoring the benthos Line intercept transectsLine intercept transects Visual transectsVisual transects QuadratsQuadrats Photography and videoPhotography and video
Line Intercept TransectLine Intercept Transect
Marine protected areasMarine protected areas Fisheries reservesFisheries reserves
– ““No take zones” (NTZs)No take zones” (NTZs)– Controlled fishingControlled fishing
Effects on fish populationsEffects on fish populations– Coral reef fish often have small ranges Coral reef fish often have small ranges
Effects on fishing revenueEffects on fishing revenue Local management and ownershipLocal management and ownership
SourcesSources The marine protected areas case studies are The marine protected areas case studies are
based on the work of Russ and Alcala.based on the work of Russ and Alcala. I think these are classic studies because they I think these are classic studies because they
show both the conservation and economic show both the conservation and economic benefits of marine reserves AND how important benefits of marine reserves AND how important co-operation with the local community can be.co-operation with the local community can be.
These are not new references, work from These are not new references, work from Roberts’s paper for newer studies. See also Roberts’s paper for newer studies. See also Gell and Roberts 2003 – Trends in Ecology and Gell and Roberts 2003 – Trends in Ecology and Evolution, 18, 448 - 455Evolution, 18, 448 - 455
Biological effects of Biological effects of protectionprotection
Habitat protectionHabitat protection BiodiversityBiodiversity Protection of Protection of
vulnerable speciesvulnerable species Allow fish to grow Allow fish to grow
to maturityto maturity Control (reference) Control (reference)
sitessites
Economic effects of Economic effects of protectionprotection
Increased size and Increased size and abundance of stock abundance of stock speciesspecies
Emmigration into fishing Emmigration into fishing grounds (Spillover)grounds (Spillover)
Insurance against Insurance against management failuremanagement failure
Tourism “spin-offs”Tourism “spin-offs” Ease of enforcementEase of enforcement
Marine reserves case Marine reserves case studystudy
Effects on fish diversityEffects on fish diversity
Effects on fish abundance and Effects on fish abundance and biomassbiomass
Factors to considerFactors to consider Costs?Costs?
– Staff, setup, Staff, setup, monitoringmonitoring
– Initial loss of fishing Initial loss of fishing revenuerevenue
Size/shape of Size/shape of reserve?reserve?– Life history and Life history and
behaviour of fishbehaviour of fish– Fishing intensityFishing intensity– 20-40% of fishing 20-40% of fishing
groundground
Can you sell it?Can you sell it?– Any spin-off Any spin-off
benefits?benefits?– Employment of Employment of
local staff?local staff?– Compromise on Compromise on
size of reserve?size of reserve? What management What management
outside reserve?outside reserve?
Impacts of tourismImpacts of tourism Terrestrial developmentTerrestrial development Land reclamation and creation of beachesLand reclamation and creation of beaches
– Mangrove removalMangrove removal– Sand on reef flatSand on reef flat
BoatsBoats– AnchorsAnchors– Diver/snorkeller impacts and fish feedingDiver/snorkeller impacts and fish feeding– SewageSewage– Harbour dredgingHarbour dredging
Ras Mohammed projectRas Mohammed project
Growth of reef tourismGrowth of reef tourism
SourcesSources This section is based on the works of David This section is based on the works of David
Medio and Julie Hawkins. A couple of their Medio and Julie Hawkins. A couple of their references are included at the end.references are included at the end.
Much other material is directly from the Much other material is directly from the Egyptian Environmental Affarirs Agency (link Egyptian Environmental Affarirs Agency (link at the end) at the end)
Divers reduce coral coverDivers reduce coral cover
…….and scare away fish.and scare away fish
Reducing diver impactReducing diver impact Mooring buoysMooring buoys Most damage Most damage
caused my minority caused my minority of diversof divers– EducationEducation– EnforcementEnforcement
Ban glovesBan gloves MonitoringMonitoring Zoning / Closure / Zoning / Closure /
RotationRotation
Managing terrestrial Managing terrestrial impactsimpacts
Catchment managementCatchment management– AgricultureAgriculture– FertiliserFertiliser
Seafront corridorsSeafront corridors Controls on sewage systemsControls on sewage systems Limits on developmentLimits on development Dry beaches and walkwaysDry beaches and walkways
Who cares what happens Who cares what happens to coral reefs anyway?to coral reefs anyway?
FisheriesFisheries TourismTourism Coastal protectionCoastal protection BioprospectingBioprospecting Moral reasonsMoral reasons Many coral reef functions are SubsistenceMany coral reef functions are Subsistence
– Do not show up as economic benefitsDo not show up as economic benefits– REPLACEMENT value may be extremely REPLACEMENT value may be extremely
highhigh
SummarySummary Coral reefs contain diverse fish and Coral reefs contain diverse fish and
invertebrate assemblagesinvertebrate assemblages– This makes them valuable, but This makes them valuable, but
difficult to managedifficult to manage Coral reefs are mainly found in the Coral reefs are mainly found in the
poorest areas of the worldpoorest areas of the world– This makes them prone to over-This makes them prone to over-
exploitationexploitation
SummarySummary Reefs must be assessed and Reefs must be assessed and
monitored to allow managementmonitored to allow management Marine protected areas may protect Marine protected areas may protect
biodiversity and maintain fish stocksbiodiversity and maintain fish stocks Diversification of local economies may Diversification of local economies may
be effective in reducing pressuresbe effective in reducing pressures Tourism brings new pressures which Tourism brings new pressures which
must also be managed.must also be managed.
Reef diversity patterns(Rosen 1981; Ormond and Roberts 1997)Urchins, Climate change, bleaching(Brown 1997; Lessios 1998; Kleypas et al. 2001)Monitoring techniquesAustralian Institute for Marine Science http://www.aims.gov.au/(English et al. 1997)Fisheries and reserves(Roberts and Polunin 1993; Roberts 1995; Russ and Alcala 1996; McManus 1997; Russ and Alcala1998; Jennings et al. 2001)Tourism and zoningEgyptian Environmental Affairs Agency www.eeaa.gov.eg/(Medio et al. 1997; Hawkins et al. 1999)
Brown BE (1997) Coral Bleaching: causes and consequences. Coral Reefs 16:S129-138English S, Wilkinson C, Baker V (1997) Survey Manual for Tropical Marine Resources. Australian
Institute for Marine Science, TownsvilleHawkins JP, Roberts CM, Van'T Hof T, De Meyer K, Tratalos J, Aldham C (1999) Effects of
recreational SCUBA diving on Caribbean coral and fish communities. Conservation Biology13:888-897
Jennings S, Kaiser MJ, Reynolds JD (2001) Marine Fisheries Ecology. Blackwell Science Ltd., LondonKleypas JA, Buddemeier RW, Gattuso J-P (2001) The future of coral reefs in an age of global change.
International Journal of Earth Sciences 90:426-437Lessios HA (1998) Mass mortality of Diadema antillarum in the Caribbean: what have we learned?
Annual Review of Ecological Systems 19:371-393McManus JW (1997) Tropical marine fisheries and the future of coral reefs: a brief review with
emphasis on Southeast Asia. Coral Reefs 16:S121-S127Medio D, Pearson M, Ormond RFG (1997) Effect of briefings on rates of damage to corals by divers.
Biol Cons 79:91-95Ormond RFG, Roberts CM (1997) The biodiversity of coral reef fishes. In: Ormond RFG, Gage JD,
Angel MV (eds) Marine Biodiversity: Patterns and Processes. Cambridge University Press,Cambridge, p 471
Roberts CM (1995) Effects of fishing on the ecosystem structure of coral reefs. Conservation Biology9:988-995
Roberts CM, Polunin NVC (1993) Marine reserves: simple solution to managing complex fisheries?Ambio 22:363-368
Rosen BR (1981) The tropical high diversity enigma - the corals'-eye view. In: Forey PL (ed) Chance,change and challenge: the evolving biosphere. Cambridge University Press, London, p 103-129
Russ GR, Alcala AC (1996) Do marine reserves export adult fish biomass? Evidence from Apo Island,central Philippines. Mar Ecol Prog Ser 132:1-9
Russ GR, Alcala AC (1998) Natural fishing experiments in marine reserves 1983-1993: communityand trophic responses. Coral Reefs 17:383-397
Top Related