1. Projected changes to coral reefs, mangroves and seagrasses
Recall location within program, recalling climate to habitats then stocks/organisms

2. Based on......

3. Outline Coastal habitats: roles and values
Requirements for good coral growth
Stresses on coral reefs
Projected effects of climate change on:
coral reefs
mangroves
seagrasses
Key management measures

4. Coral reefs major part of habitats, but this talk is more than reefs
Coral reefs major part of habitats, but this talk is more than reefs. Interconnectivity among habitats.

5. Requirements for good coral growth
Warm water temperatures
Shallow well-lit waters
Low sediment and nutrients
Right ocean chemistry
Coral reefs grow in the warmest parts of oceans & have a narrow temperature range

6. Corals must build skeletons fast enough to withstand natural forces of erosion
waves
cyclones & storms
Balance battle of erosion and accretian. Gowth to overcome forces . Point out bioeroders later.
bleaching
predators
coral eaters

7. A special relationship
Symbiosis at heart of tropical coral reefs
Photosynthetic algae live within coral animal
Corals get enough energy for rapid calcification
Form structurally complex reefs
Home to thousands of other plants and animals
How corals grow… symbiosis. Cells of algae in photo.

8. Stresses – higher water temperatures
Stressed corals lose algae (and their pigments)
Coral bleaching
Corals living only ~1-2oC below upper thermal limit
Too much freshwater can also cause bleaching
Threshold bleaching NOAA bleaching alerts
Healthy - unbleached
Stressed - bleached
Recently dead

9. Stresses – ocean acidification
30% extra CO2 entered ocean
Changes ocean chemistry
Harder to form skeletons
Greater coral erosion
Refer back to johan’s talk. Result, corals have to compete with other erosive forces,

10. Ocean acidification: natural laboratory
High CO2 volcanic seeps, PNG
“Winners” = massive corals
“Losers” = branching, tabulate corals
Reduced coral diversity
Much simpler reef with lower pH
Normal pH = now
Mid pH = 2050
Lower pH = 2100
West New Britian. Not a total disappearance of corals…. But simplification.
Fabricius et al 2011

11. Source: http://coralreefwatch.noaa.gov/satellite/vs/index.html

12. Projected Effects of Climate Change on Coral Ecosystems
Take out sea

13. Projected Regional Climate Change
1980–1999
average
2035 A2
2050 A2
2100 A2
Air temperature (°C)
27.4
+0.5 to +1.0
+1.0 to +1.5
+2.5 to +3.0
Sea surface temperature (°C)
27.3
+0.7 to +0.8
+1.2 to +1.6
+2.2 to +2.7
Rainfall: equatorial (%)
Rainfall: subtropics (%)
n/a
+5 to +20
-5 to -20
+10 to +20
Sea level (cm)
+6a
+20 to +30
+70 to +110
+90 to +140
Ocean pH (units)
8.1
-0.1
-0.2
-0.3
Cyclones & storms 9
Number of cyclones/storms may decrease but likely to be more intense
pH is a logarithmic scale, a difference of one pH unit is equivalent to a tenfold difference in hydrogen ion concentration.
a = since 1960

14. Warmer water temperatures
Reefs very high vulnerability
Increased bleaching, ~1% loss per year by 2035
Average los of 1% per year…expecting to continue if not get worse. Recent observations

15. More acidic ocean Reefs have high vulnerability Weaker reef frameworks
Growing quickly, future not grow quickly, dead coral dissolution more easily. Aragonite threshold, already in deep ocean, so low will dissolve. Softer easier for bioerosion.

16. Stronger storms and heavier rainfall
Moderate vulnerability of reefs
More disturbances = less time to recover
Turbidity- runoff light penetration,

17. Higher sea level
Some corals may keep up
Loss of deeper corals

18. Coral reefs will not disappear entirely BUT MUCH SIMPLER ECOSYSTEMS
What climate change means for reefs
More bleaching and diseases
Weaker skeletons
Physical destruction
Less time to recover between disturbances
Healthy reefs better able to cope
Coral reefs will not disappear entirely BUT
likely to be
MUCH SIMPLER ECOSYSTEMS

19. CORAL DOMINATED TO
ALGAL DOMINATED
REEFS

20. Projected loss of coral reefs
2050 A2
2100
>90% Loss Of Coral Cover by 2100

21. Mangroves: role & value

22. Vulnerability of Mangroves
Most vulnerable to:
sea-level rise
increasing storm intensity
Ability to adapt by migrating landward as sea-level rises but human barriers may constrain movement
Overall moderate-high vulnerability to climate change

23. Overall vulnerability of mangroves
Sea surface temperature
Solar radiation
Ocean chemistry
Cyclones & storms
Rainfall patterns
Sea level
Nutrients
Mangroves 2035 A2
Very low
Low
Moderate
High
2050 A2
Very high
2100 A2

24. Projected loss of mangroves in VANUATU
From 25 km2 today:
Year
Mangrove area (%)
2035
-10
2050
-50
2100
-60
CAN REFERENCE

25. Vulnerability of seagrasses
Most vulnerable to:
Warmer waters
Increased rainfall (turbidity)
Increasing storm intensity
Reduced light
Limited ability to adapt
Overall moderate vulnerability to climate change
Burn -

26. Overall vulnerability of seagrasses
Sea surface temperature
Solar radiation
Ocean chemistry
Cyclones & storms
Rainfall patterns
Sea level
Nutrients
Seagrasses 2035 A2
Moderate
Very low
Low
2050 A2
2100 A2
High

27. Projected loss of seagrass in Vanuatu
From ?? km2 today:
Year
Seagrass area (%)
2035
-5 to -20
2050
-5 to -30
2100
-10 to -35

28. Key management measures
Build health of coral reefs, mangroves and seagrass by addressing existing threats:
Integrated catchment management
Foster the care of coastal fish habitats
Manage and restore coastal vegetation
New measures to allow future adaptation of mangroves:
Provide for landward migration
Adaptations talk…

29. Conclusions
Coral reefs, mangroves and seagrasses in Vanuatu Islands are expected to decline in area due to climate change
Acting now to manage existing threats and allow for future adaptation is vital for these habitats
Coastal fisheries that depend on these habitats will be affected as these habitats degrade