A Fundamental Approach to Coral Reef Monitoring and

Assessment in theCNMI and American Samoa

Marine Biologist Peter Houk PhD Candidate CNMI Division of Florida Institute of Environmental Quality Technology

Fundamental Approach to Monitoring and Assessment of

Reefs

• Processes Regulating Reef Development• Example 1 – Northern Mariana Islands,

CNMI • Example 2 – Southern Mariana Islands,

CNMI • Example 3 – American Samoa

Processes Regulating Reef Development

• Initially, volcanic activity created islands, substrate for reefs to grow

• Location and extent of reef growth are dictated by (Macro-scale Factors) – Temperature – Historical sea level

fluctuations – Tectonics – Wave energy

• Historical Temperature and Sea Level Relationship – Historical growth created

today’s reef structure

Foram fossil cores

Processes Regulating Reef Development

• Tectonic Activities on Rota – Uplifting – Cores identify coral

reef growth in the past – Uplifted Holocene

deposits prevent “normal” Mariana Islands reef flat communities

Processes Regulating Reef Development

• Wave energy – Determines the type of

community growth – Wave energy acts

differently along a depth gradient

Geister, 1977

Munk and Sargent, 1948

Processes Regulating Reef Development

The integrated result that we see is the – reef geomorphology (reef

structure) – Living “organic” reef

Understanding macroecology is key for present monitoring and assessment of coral reefs

Fundamental Approach to Monitoring and Assessment of

Reefs

• Processes Regulating Reef Development• Example 1 – Northern Mariana Islands,

CNMI • Example 2 – Southern Mariana Islands,

CNMI • Example 3 – American Samoa

Example 1 – Northern Mariana Islands

• Situated on active Marianas Ridge

• 1 – 5 million years old • Mostly uninhabited • Few previous studies • Management plans for coral

reefs desired

NMI

0 - 2 cm 2 - 4 cm 4 - 8 cm 8 - 16 cm 16 - 32 cm 32 - 64 cm >

Size Class

Holocene Deposits

Volcanic Boulders

nity Evenness (Margalef s DStat st c) X 10

Population Density Coral Coverage

HoloceneVolcanic

Example 1 – Northern Mariana Islands

• Different present communities from different geologicalsettings

• What processes are acting against thesesettings?

• Is it possible to classify setting beforecompare and contrastsites?

0

5

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45

64 cm

Perc

enta

ge o

f Cor

al C

olon

ies

0

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35

40

Commu ' -i i

?

Example 1 – Northern Mariana Islands

• To begin to understand impacts of feral animals we first use regional Feral

characteristics Animals

– GUG 2, ALA 3 have living, organic reef situated mainly on limestone reef deposits, not volcanic rock

– wave energy No Feral Animals

Example 1 – Northern Mariana Islands

• Several coral community measuresshow little difference between sites

• What is impact of feral animals compared with naturalcommunity regulationprocesses at thissite?

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Community Evenness (Margalef's D-Statistic)

Population Density Geometric Diameter Coral Species Richness

GUG - 2

ALA - 3

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0 - 2 cm 2 - 4 cm 4 - 8 cm 8 - 16 cm 16 - 32 cm 32 - 64 cm > 64 cm

Size Class

Perc

enta

ge o

f Col

onie

s ALA-3 GUG-2

Fundamental Approach to Monitoring and Assessment of

Reefs

• Processes Regulating Reef Development• Example 1 – Northern Mariana Islands,

CNMI • Example 2 – Southern Mariana Islands,

CNMI • Example 3 – American Samoa

SMI

Example 2 – Southern Mariana Islands

• Increased complexity in geological settings – 1) Antecedent,

Holocene Deposition (indicator)

– 2) Pleistocene or earlier only (indicator)

• Wave energy consideration

Example 2 – Southern Mariana Islands

• Holocene (recent) deposits not related to exposure

• Deposits = topographic complexity, result ofsediment trapping

• In circular nature, topographic reliefprovides refuge fromscouring physicalenvironment, and continues to build

Holocene

Deposition

No Holocene Deposition

Example 2 – Southern Mariana Islands

• Living organic reef community

– Favia, Leptastrea, Pocillopora account for >30% of measured coral

– * = significant difference – = no significant difference 0.00

2.00

4.00

6.00

8.00

Acr

opor

a

Ast

reop

ora

Favi

a

Gon

iast

rea

Lep

tast

rea

Mon

tipor

a

Pavo

na

Poci

llopo

ra

Pori

tes

Styl

opho

ra

Cor

al P

opul

atio

n D

ensi

ty (#

per

m2 ) Holocene Deposits

No Holocene Deposits

*

** **

*

*

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0 - 2 cm 2 - 4 cm 4 - 8 cm 8 - 16 cm 16 - 32 cm 32 - 64 cm Geometric Diameter Size Class

% o

f Col

onie

s

Favia, Holocene Deposits Favia, No Holocene Deposits

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0 - 2 cm 2 - 4 cm 4 - 8 cm 8 - 16 cm 16 - 32 cm 32 - 64 cm Geometric Diameter Size Class

% o

f Col

onie

s

Leptastrea, Holocene Deposits Leptastrea, No Holocene Deposits

with Holocene deposition

Exp

osur

e Fa

ctor

(rad

x m

)

Example 2 – Southern Mariana Islands

• Wave energy considerations– Holocene reefs From NOAA buoy data – P. rus dominant reefs in

extremely sheltered locations

14

12

10

8

6

1

2

3

45

6

7

8

Y = 7.81 - 1.38x R2 = .52

N4

2

0

Quadrant Exposure Direction Exposure Degrees Average Wave Height (m) 1 N - NE 0 - 45 1.5 2 NE - E 45 - 90 1.4 3 E - SE 90 - 135 1.2 4 SE - S 135 - 180 0.7 5 S - SW 180 - 225 0.7 6 SW - W 225 - 270 0.7 7 W - NW 270 - 315 0.7 8 NW - N 315 - 360 0.9

0.0 1.0 2.0 3.0 4.0 5.0

Log Abundance of Porites rus (cm2)

Example 2 – Southern Mariana Islands

• Porites rus dominance, lower species diversity in extremely sheltered regions expected =

Example 2 – Southern Mariana Islands

• Macroecology information required before assessments of land based disturbances and such

• Compare site in questions with regional information

• Use watershed characteristics, stream flow rates, water quality data, and others, to complimentreef community data (sitespecific studies)

?

Talakhaya Watershed, Rota Island

Turf Algae Cover

Coralline Algae Cover

Fundamental Approach to Monitoring and Assessment of

Reefs

• Processes Regulating Reef Development• Example 1 – Northern Mariana Islands,

CNMI • Example 2 – Southern Mariana Islands,

CNMI • Example 3 – American Samoa

Example 3 – American Samoa • Watershed based

management and water quality monitoring

• Reefs used as bio-criteria indicators to water quality health (EPA guidance)

• Simultaneously, initiate long term monitoring baseline

Arrows indicate similar geomorphology

Example 3 – American Samoa

• Similar geomorphology at Aoa, Leone, and Alofau

• This setting allows for larger corals, greater coverage, dueto stable abiotic environment

• NOT imply “better condition”(low community evenness)

• Stability ≠ Diversity

Example 3 – American Samoa • Size Distribution of Coral

Colonies

• Multivariate exploratory techniques (Multi-DimensionalScaling), using coral relativeabundances

Houk, Didonato, and Iguel, submitted EMAS

Example 3 – American Samoa • Compare Sites with same

regional characteristics • Coral cover crude indicator

for reef health assessment based upon coral community

• Community evenness • Geometric diameters • Overall diversity Acropora clathrata

Houk, Didonato, and Iguel, submitted EMAS

Conclusion • Environmental settings

are important forunderstanding living reefs

• Elucidate processes that regulate coralcommunities

• Gain regional understanding to providecontext for local assessments

Aguijan Island, CNMI

Conclusion

• Through monitoring we greatly enhance the ability to properly manage and protect coral reefs

• Thanks to: – US Environmental Protection Agency – CNMI Division of Environmental Quality – CNMI Coastal Resources Management Office – American Samoa Environmental Protection Agency – CNMI Marine Monitoring Team – NOAA MARAMP, NOAA CREI Division