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 Reduction of fishing effort to sustain all

fish species wastes the productivity of fish species wastes the productivity of most stocksmost stocks

Non-selective and Non-selective and destructive fishing methodsdestructive fishing methods Subsistence fishing occurs Subsistence fishing occurs

regardless of effort requiredregardless of 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 symbiotic algaealgae

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 Multiple re-occurrences at same

sitessites 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 Management of a multispecies fishery is extremely complex, and fishery is extremely complex, and often failsoften fails

Terrestrial development may destroy Terrestrial development may destroy coastal reef systemscoastal reef systems

Global climate change may exert Global climate change may exert new pressuresnew pressures

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 benefits of marine reserves AND how important co-operation with the local important co-operation with the local community can be.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 Control

(reference) sites(reference) sites

Economic effects of Economic effects of protectionprotection

Increased size and Increased size and abundance of stock abundance of stock speciesspecies

Emmigration into Emmigration into fishing grounds fishing grounds (Spillover)(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 What

management 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 Diversification of local economies may be effective in reducing may be effective in reducing pressurespressures

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