Science To Action:Recent Research Results Useful in Seagrass Management in the Philippines

M.D.FortesPhilippines

BolinaoSeagrass Reserve

REVERSING ENVIRONMENTAL DEGRADATION TRENDS IN THE SOUTH CHINA SEA AND GULF OF THAILAND

WWW.UNEPSCS.ORG

…many publishedworks on seagrass

science, very few on its

‘management’…practically none, linking science

directly to ‘true management’

SCIENCE : MANAGEMENT LINKAGE?

SiltationCoastal fish aquaculturePhysical disturbance

Objective & FrameworkTo provide scientific knowledge & models needed to promotethe sustainable use of seagrass resources in the Philippines

Seagrass Ecosystems

Analysis of the effects on the structure & function of the ecosystemEvaluation of its resilience & recovery

COASTAL MANAGEMENT

REVERSING ENVIRONMENTAL DEGRADATION TRENDS IN THE SOUTH CHINA SEA AND GULF OF THAILAND

WWW.UNEPSCS.ORG

81

1916

13 12 11

7

3 31 1 1

0

10

20

30

40

50

60

70

80

90

No

of s

peci

es

Mollusca

Echinoderms

Porifera

Chlorophyta

Cnidaria

Chordata

Magnoliophyta

Arthropoda

Annelida

Rhodophyta

Heterokontophyta

Foraminifera

1 7 13 19 25 31 37 43 49 55 61 67 73 79 85 91 97

A

B

G

F

E

D

C

DistanceTr

anse

ct

Total seagrass density

90-10080-9070-8060-7050-6040-5030-4020-3010-200-10

473

406

170

559 4

39 54

657

1

8956

0

100

200

300

400

500

600

700

Num

ber o

f Ind

ivid

uals

SiganidaeLabridaeMullidaeLutjanidaeMuraenidaeSerranidaeNemipteridaeCypraeidaeStrombidaeConidaeToxopneustidaeHolothuridae

FishSpecies

Gastropods

Echinoderms

BolinaoSeagrassReserve

Total seagrass density

Associated species densityDensity of economic species

High biodiversity, seagrass density, & abundance of commercial species within the reserve:

• Underlies the ecological & economic value of the reserve, & highlights the need for it’s preservation.

• The reserve, if protected, could potentially serve to enhance the health of surrounding local & regional ecosystems.

• The data collected will serve as a baseline for future monitoring to assist management.

ASSESSMENT: Main Finding & Implications

REVERSING ENVIRONMENTAL DEGRADATION TRENDS IN THE SOUTH CHINA SEA AND GULF OF THAILAND

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Pollen can travel up to 19.2 km day-1

High “pollen rain”:~ 160 pollen grains per male flower~ 480 male flowers per inflorescence~ 76,800 pollen grains per inflorescence

•• Dispersal distance of Dispersal distance of E. E. acoroidesacoroides seeds is shortseeds is short& & recolonisationrecolonisation beyond existing beds is limitedbeyond existing beds is limited

• Genetic diversity may primarily depend on the long distance dispersal capability of pollen grains (male flowers)

SEED BIOLOGY: Main Findings & Implications

REVERSING ENVIRONMENTAL DEGRADATION TRENDS IN THE SOUTH CHINA SEA AND GULF OF THAILAND

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High respiratory, community becomes heterotrophic, soil more acidic

More silt & clay = less no. of species

Increase in sediment sulfide, detrimental toseagrassesSI, most silt sensitive; EA, least

EFFECTS

OF SILT,

LIGHT,

SULFIDE

ON

SEAGRASS

Effects of coastal milkfish aquaculture on the water column & sediment

0

2

4

6

8

10

F3TR1 F3TR2 F4TR1 F5TR1 F6TR1

Ligh

tex

tinc

tion

coe

ffic

ient

(m

-1) Inside

100 m outside1 km outside

15-25 m outside50 m outside

Light availability to seagrassesstrongly reduced (Duarte 1991)

0 20 40 60 80 1000

100

200

300

400

500

600

Sedi

men

tati

on r

ate

(g D

W m

-2d-

1 )

Distance to fishpen (m)

High organic matter loadings

•Increased concentration of dissolved inorganic nutrients in water•Sediment is enriched in organic matter by a factor 4

EUTROPHICATION

REVERSING ENVIRONMENTAL DEGRADATION TRENDS IN THE SOUTH CHINA SEA AND GULF OF THAILAND

Female flowers are more likely to produce a fruit as seagrass cover of the substratum increases above 40 %

…more seagrass species away from fishpens

SEAGRASS (& SEDIMENT)RECOVERY VERY SLOW, MOST

SUCCESSFUL THRU SEXUALREPRODUCTION

FRUITING&

RECRUITMENT

Remarkable increase in the number of shoots (& % survival) of transplants in all three sitesSilted sites could be rehabilitated using pioneer seagrass transplants

SEAGRASS TRANSPLANTATION

Research results for sustainable use of SE Asian seagrass resources

• Detrimental siltation level: 10 – 15 % of sediment dry weight• Loss of species richness & biological production• Ranking of seagrass species in terms of sensitivity to siltation• Seagrasses as indicators of detrimental siltation loads to coastal ecosystems• A 25% - 30% reduction in light availability determines community heterotrophy• Enrichment of sediment with OM by a factor 4 is detrimental to seagrasses• Sediment conditions deteriorate fast & recover slowly (years)• Seagrass recovery is slow (years) & dependent on sexual reproduction mostly• Sexual reproduction is negatively affected by siltation & spatial fragmentation• Cover threshold for succesful fruit production: 40 %• Silted sites could be rehabilitated using transplants of pioneer seagrass species

SiltationWater column

Sediment

Seagrass loss

Physical disturbance

Milkfish aquaculture

Seagrass recoverySexual reproductionSpatial fragmentationPlant abundance

ACTIONTWO TOWN MAYORS SIGNEDAGREEMENT TO CLEARCAQUIPUTAN

Too many fish structures along waterways

Increases residencetime of sediments & fish feeds

Decimatesseagrass & otheroxygen providers

Anoxia

FISH KILL

LESSONS• Fish structures should be in areas where water is easily renewed

• Do not block channels• Efforts should be a concerted one• Removal of fish structures in narrow channels will improve the system

DECISIONA TOTAL OF 2.7 KM NEED TO BE CLEARED IN CAQUIPUTAN

SCIENCE TO ACTION: A CASE STUDY

Sea level rise

Sea level rise

Increased COIncreased CO22Seawater warming

Seawater warmingnewnew

habitathabitat

submarine

submarine

erosionerosion

photophoto--synthesissynthesis

reducedreducedcalcificationcalcification

reproduction

reproduction

habitat expansion

habitat expansion increased

increased respiration

respiration

Forecasted effectsForecasted effectsof climate change of climate change on seagrasson seagrass(Modified from Duarte 2002)

Climate changeClimate change

M

S

C

STRUCTURE FUNCTION USES STAKEHOLDERS

Sp compositionSp compositionDistributionDistributionBiomassBiomassDensityDensityCover, etc.Cover, etc.

ProductionProductionCarrierCarrierRegulationRegulationInformationInformation

BiodiversityBiodiversityFoodFoodMedicineMedicineProtectionProtectionLiving space,Living space,Materials, etcMaterials, etc..

CommunityCommunityNGOs, NGOs, POsPOsIPsIPsLGUsLGUsAcademeAcademeIndustry, etc.Industry, etc.

AWARENESS >>> UNDERSTANDING >>> ADOPTION >>> ACTION

MULTI- & INTERDISCIPLINARY INTEGRATION

SOUND RESOURCES MANAGEMENT

Science on ecosystem linkages: basis for management

In the seas of East Asia, coral reefs are the most popular, mangroves, the most disturbed, & seagrass beds, the least studied. Unless managed, the reefs will collapse within 20 years, all mangroves will be lost by 2030. Fisheries in the region is largely dependent upon these habitats. But with the predicted total collapse of world fisheries by 2048, we need to rethink, especially that which we call ‘development’.

The UNEP/GEF SCS Project has shown that seagrasses are as important as reefs & mangroves. The ecosystem could be a ‘last frontier’ in tropical coasts. Thus, the project has initiated a regional effort to manage seagrasses. But we need to link the results of their science directly with policy in their management. It will be a long winding road ahead, but we are getting there.

CONCLUSION

REVERSING ENVIRONMENTAL DEGRADATION TRENDS IN THE SOUTH CHINA SEA AND GULF OF THAILAND

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