Effect of climate change and contrasting land use patterns on historical dynamics of reef-building corals in Puerto Rico: A story about increased ecosystem vulnerability and ecological collapse

Edwin A. Hernández-DelgadoRaisa Hernández-Pacheco,Tagrid Ruiz-Maldonado

University of Puerto Rico, Department of Biology,Center for Applied Tropical Ecology & ConservationCoral Reef Research Group, UPR-RPcoral_giac@yahoo.com

NSF External Scientific Advisory Committee SymposiumCenter for Applied Tropical Ecology and ConservationUPR-RP, November 12-14, 2009, San Juan, PR

Objectives

• Brief overview of current coral reef crisis.

• Project’s research questions and goals.

• Preliminary findings.

• Additional current and future steps.

http://www.cartoonstock.com/directory/d/dying.asp

Coral ReefRIP

Mrs.Globalization

Mrs.Reductionist

Science

Facts

• Sea surface temperatures and CO2 concentrations have reached unprecedented high levels during the present decade.

• Current sea surface warming and ocean acidification trends (as a result of increased CO2 concentrations) have driven coral reef ecosystems into an unprecedented state of vulnerability.

• Reef deterioration often occurs in response to multiple stressors acting simultaneously or synergistically.

Facts• A single sea surface warming event in 2005

caused an unprecedented coral mortality event in the Caribbean at least within the last 220,000 years (Pandolfi & Jackson, 2006).

• A degraded environment has a strong influence on coral reef resilience. Declining environment increase reef vulnerability to sea surface warming (=bleaching) and reduce its resilience.

• Time scales necessary for coral reef recovery from any type of disturbance will increase with increasing spatial scales of impacts.

Facts

• Coral reefs are going into a state of ecological collapse if conditions necessary for recovery are inadequate.

• Coral reefs vulnerability to environmental changes, including disrupted carbon cycle pathways (acidification), may lead to potential mass extinction events in the near future.

Facts

• Under the current very rapid rates of climate change (100-1,000 times that of the most rapid environmental changes over the past 420,000 years at least), coral slow rates of evolutionary change are unlikely to keep pace.

• The time scale of most current impacts (months to decades) is so fast that corals evolutionary adaptation (millennia at least) is not even an option.

Facts

• Puerto Rico is undergoing continuously increasing pressures of development, with simultaneously rapid declining environmental and socio-economic conditions. These have resulted in net long-term coral reef declines.

• Current spatial magnitude of coral mortality will require radical actions and decisions, both in land and sea.

• Under current pace of decline large-reef building corals will require a recovery time scale out of our context.

Research questions• Historical trends

• Which have been the recent historical trends in proxy signals recorded in reef-building coral annual growth bands to climate change dynamics as well as changes in land-use patterns in the dry karstic zone in PR?

• Current and future trends

• What are the effects of climate change and localized anthropogenic factors on coral reef ecosystem dynamics?

“Montastraea annularis”• Species complex:

– M. annularis.– M. faveolata.– M. franksi.

• Wide bathymetric distribution (>60 m), principal reef-builder in the Atlantic.

• Simultaneous hermaphrodites.

• Annual reproductive cycles.

• Extremely low sexual recruitment rates.

• High recruit mortality rates.M. faveolata

“Montastraea annularis”

• Annual skeletal growth rate <1 cm.

• Highly susceptible to different diseases and/or syndromes.

• Inability to recover lost tissue following disease/syndrome impacts.

• Susceptible to prolonged exposure (>8-15 DHWs) to SSTs 1-2°C above MMM.

• Susceptible to chronic water quality degradation (i.e., transparency, sedimentation, eutrophication). Bleached M. faveolata

“Montastraea annularis”• Susceptible to a wide diversity of

competitors (i.e., sponges, encrusting tunicates, algae, cyanobacteria).

• Deepwater (>30 m) colonies appear to be in better shape than those from shallower reefs.

• All surveyed shallow-water reefs (<20 m) show at least a moderate degree of population declines.

M. annularis

Water transparency (m)

0 5 10 15 20 25 30

% C

over

M.

annu

laris

0

10

20

30

40

50

60

y= -4.57 + 1.42xr= 0.8488, p<0.0001

Declining M. annularis abundance withincreasing water turbidity

Threshold intransparency?

Mann

6E-2

0.24

0.42

0.6

Low

Low

Low

Low

Low

Moderate

Moderate

ModerateHigh

HighHigh

High High

Bombarded

Moderate

Moderate

LowLow

Bombarded

High

2D Stress: 0.13

CR1

Year

- 1997 - 1998 - 1999 - 2001 - 2002 - 2003 - 2004 - 2005 - 2006 - 2007 - 2008 - 2009

% C

oral

cov

er

0

20

40

60

80

100

<4 m4-8 m>8 m

Repeated Measures ANOVAYear p<0.001Depth p=0.2881Year x Depth p=0.9999

Significant coral reef decline within 1997-2009

-81%

-69%

CR1

Time

- 1997 - 1998 - 1999 - 2001 - 2002 - 2003 - 2004 - 2005 - 2006 - 2007

% C

ove

r M

. a

nn

ula

ris s

pp.

com

ple

x

0

10

20

30

40

50

Collapsing population ofMontastraea annularis

-72%

-52%

Other examples from PR

Sites

PF

L

PC

R

CLP

-S

IBE

CB

T

PS

O

CS

J

PLT

PLM DIA

NE

G

CA

R-S

CA

R-D

PS

AR

PA

R-N

PA

R-S

PM

UJ

PC

AR

% C

oral

cov

er

0

20

40

60

80

100

1999 20052007

Culebra Fajardo CR Mona

Eastern PR coast: M. annularis species complex population collapse?

Site

PLT PLM CDI PFL PCR CBT

% C

over

M.

annu

laris

com

plex

spp

.

0

10

20

30

40

50

60

2003 2005 2007

Anomalies

Period

Jan

1-15

Jan

16-3

1

Feb

1-1

5

Feb

16-

28

Mar

1-1

5

Mar

16-

31

Apr

1-1

5

Apr

16-

30

May

1-1

5

May

16-

31

Jun

1-15

Jun

16-3

0

Jul 1

-15

Jul 1

6-31

Aug

1-1

5

Aug

16-

31

Sep

1-1

5

Sep

16-

30

Oct

1-1

5

Oct

16-

31

Nov

1-1

5

Nov

16-

30

Dec

1-1

5

Dec

16-

31

Tem

pera

ture

(C

)

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

2003 2004 2005 2006 2007 2008

Monthly Maximum

Year-round thermal anomalies (2003-2008)

Mass bleaching impacted M. annularis complex

• Montastraea spp. impacts:

– M.annularis 97.1%– M. faveolata 90.4%– M. franksi 92.1%– M. cavernosa 36.7%

% Bleaching

0 20 40 60 80 100

Spe

cies

CbreSrad

MmeaDcylPdivPbra

AhumAtenAfraLcucFfrag

IsinMsquBasbPfur

MannAagaMfraMfavMalcDlabPporAlamEcarAcerAgra

McomSsidCnatDstrMfer

IrigDcli

PastMcavApal

*

**

*

Hernández-Delgado et al., unpub. data

Montastraea annularisMann

6E-2

0.24

0.42

0.6

Sha1Sha2

Sha3

CSJ1

CSJ2

CSJ3

CLA1

CLA2

CLA3

PLT1PLT2PLT3

PLT4

PLT5

PLT6

PLT7

PLT8

PLM1

PLM2

PLM3

PLM4

PLM5PLM6

PLM7

PLM8

PLM9

SDP1

SDP2

SDP3

SDP4DIA1

DIA2

DIA3DIA4

PFL1

PFL2PFL3

PFL4

PFL5PFL6

PFL7

PFL8

PFL9

PFL10PCR1

PCR2

PCR3

PCR4

PCR5

PCR6

PCR7

PCR8 PCR9

PCR10

PCR11

PLAR1

PLAR2

PLAR3

PSOL1

PSOL2

PSOL3

PSOL4PSOL5

PSOL6

PSOL7

PSOL8

PSOL9PSOL10

CBT1 CBT2

CBT3CBT4

CBT5

2D Stress: 0.2

Community structure and oceanographic patterns influenced bleaching severity

Severe

Moderate

Minimum

Limitedcirculation

Moderatecirculation Strong

Circulation

Mona Island’s coral reefs are also collapsing

Site

CAR (5-1

0 m

)

CAR (10-

15 m

)

SAR (5 m

)

ARE (5 m

)

MUJ (

15-2

0 m

)

PCA (10-

12 m

)

% C

oral

0

10

20

30

40

Garcia (2000)

Garcia (2000)

Ferrer y Canals (1981)

Hernandez (1997)

Hernandez (1993)

Hernandez (1997)

Abrupt decline in % living tissue cover

Sites

CAR-S CAR-D PSAR PAR-N PAR-S PMUJ PCAR

% C

oral

cov

er

0

5

10

15

20

25

30

35

Pre-mortalityPost-mortality

Major reef-building species undergoingsignificant mortality

• Most large reef builders have recently died or have suffered significant partial mortality.

• High prevalence of YBD and other syndromes.

Montastraea annularis

% F

requ

ency

0

20

40

60

80

100Montastraea faveolata

PMYBDRTMWP

Coplpohyllia natans

% F

requ

ency

0

20

40

60

80

100Agaricia agaricites

Diploria clivosa

Site

CAR (5-1

0 m

)

CAR (10-

15 m

)

SAR (5 m

)

ARE (5 m

)

MUJ (

15-2

0 m

)

PCA (10-

12 m

)

% F

requ

ency

0

20

40

60

80

100Diploria strigosa

Site

CAR (5-1

0 m

)

CAR (10-

15 m

)

SAR (5 m

)

ARE (5 m

)

MUJ (

15-2

0 m

)

PCA (10-

12 m

)

Dramatic post-bleaching loss in % living tissue cover followed by physiological fragmentation (2005-2009)

Significant mortality in smaller size categories

Preliminary modeling of populationsurvival and growth suggest thatrecovery is unlikely and that they might be prone to extinction under recurrent sea surface warming and bleaching asmost climate models predict.

Long-term consequences of climate change and other human insults in coral reef functional roles

Colony physiology,

Holosimbionts,

Microbes

Declining foodProduction!

Further steps

• Develop studies regarding bioerosion rates under different environmental conditions.

• Document coral recruitment rates.

The past is still the key to the present!

• Joint efforts between CATEC, CCRI, and IRS to develop large scale sclerochronological studies to:

– Address historical rates of ecological change across large spatial scales.

– Determine historical patterns of change in coral reefs across anthropogenic gradients (Guanica, Mona, SW PR shelf, NE PR shelf).

– Discriminate between historical trends of localized human impacts and climate change.

Apply sclerochronological tools to address impacts of climate change on physiological fragments

• Address impacts of colony physiological fragmentation on:

– Skeletal extension rates.– Skeletal density.– Calcification rates.

– Test impacts on different fragment size categories.

– Test hypothesis regarding before-after coral ability (or inability) to recover from recurrent mass bleaching events (1987, 1998, 2005).

A final thought• “The outlook for reefs in the face of

today’s rapid global warming is exceptionally serious” (Veron, 2008).

• “The imminent demise of reefs is perhaps the strongest signal yet that the planet is on the brink of an environmentally-led mass extinction” (Veron et al., 2009).

• Whether or not this is so, “reefs are likely to be the first major planetary-scale ecosystem to collapse in the face of climate changes now in progress” (Sheppard et al., 2009).

A final thought

• There is still a paramount need to:

• Reduce harvests of herbivorous fish to sustainable levels.

• Protect and restore top predators to maintain effective food webs.

• Restore water quality (by also protecting watersheds, managing land use, reducing non-point source pollution and improving sewage treatment efficiency).

A final thought• There is still a paramount need to:

• Reduce other sources of anthropogenic stressors (to reduce cumulative and/or synergistic impacts).

• Establish additional networks of marine protected areas (to protect and enhance connectivity).

• Coral farming and reef rehabilitation (to restore coral ecological functions, foster coral sexual reproduction and improve resilience).

• Reduce greenhouse gas emissions (to prevent further screwing up Mother Earth)!!!

Acknowledgements• This presentation was made possible by:

• NSF through UPR-CREST-CATEC• NOAA/CSCOR (NA04NOS4260206, NA05NOS4261159,

NA07NOS4000192 through CCRI/UPR).• NOAA/CRCP (NA05NMF4631050 to UPR/CRRG).

coral_giac@yahoo.comhttp://ccri.uprm.edu/

http://crest-catec.hpcf.upr.edu/

787-764-0000, x-2009