coral bleaching in the hawaiian islands€¦ · (10-75%) 36% (16-65%) exposure triggers bleaching...
TRANSCRIPT
Coral Bleaching
in the Hawaiian Islands
Kohana’iki
What is Bleaching?
Photo credit: Mike Hazard
Afte
r GB
RM
PA
, 20
08
What causes
bleaching?
What causes
bleaching?
Historical Background
Bleaching Will Occur More Frequently
2030s: Mass Bleachingin 30-50% of years
2050s: Mass Bleaching In 80-100% of years
Do corals have the ability to adapt to temperature change?
EconomicTourismFishing
Shoreline Protection
Coral Reef Ecosystem
Social/Cultural value
Coral loss-What’s at stake?
2014 – 2015 Hawaiian Bleaching Event :What we know.
2014-2015: In HawaiʻiUnprecedented Back-to-Back Mass Bleaching
2014-2015: In HawaiʻiUnprecedented Back-to-Back Mass Bleaching
Temperature
2014-2015: In HawaiʻiUnprecedented Back-to-Back Mass Bleaching
Temperature
Bleaching
2014-2015: In HawaiʻiUnprecedented Back-to-Back Mass Bleaching
Temperature
Bleaching
Sep
2014
Sep
2015
2014-2015: In HawaiʻiUnprecedented Back-to-Back Mass Bleaching
Hawaii Coral Bleaching Collaborative Dataset: Main Hawaii Islands, 2014-2015
6 Institutions: • DLNR/DAR, UHM (HIMB),
UHH,TNC, HIHWNMS,NOAA-ESD
- 11 Groups- 895 Obs.- 2014-01-12 :
2016-02-15
Nearly half of all corals in the state bleached:
46% +/- 4%PercentAffected
Statewide
Nearly half of all corals in the state bleached:
46% +/- 4%PercentAffected
Statewide
56%(23-91%)
44%(6-66%)
32%(10-75%)
36%(16-65%)
2013 to 2016 Mortality EstimatesMany, Many Corals Died:Change in Coral Cover Before and After 2015 Event
Pe
rce
nt
Live
Co
ral C
ove
r
2013 to 2016 Mortality EstimatesMany, Many Corals Died:Change in Coral Cover Before and After 2015 Event
Pe
rce
nt
Live
Co
ral C
ove
r
47%61%
42%
48%
50-75%7-85%
51-57%
2013 to 2016 Mortality EstimatesMany, Many Corals Died:Change in Coral Cover Before and After 2015 Event
Pe
rce
nt
Live
Co
ral C
ove
r
47%61%
42%
48%
8-30%
~0.5%
50-75%7-85%
51-57%
2013 to 2016 Mortality Estimates:Coral Cover Lost
We asked what spatial variables correlated with
more or less bleaching: 56%
(23-91%)
44%(6-66%)
32%(10-75%)
36%(16-65%)
Exposure triggers bleaching impacts.Temperatures Above ThresholdLight
Resistance limits exposure’s damage.Sewage reducesPrevious thermal stress (2014) reducesTemperature Variability enhances
Recovery returns reefs to normal.Keep algae low (many herbivores, low nutrients)Promote coral growth/reproduction
Exposure triggers bleaching impacts.Temperatures Above Threshold Light
Resistance limits exposure’s damage.Sewage reducesPrevious thermal stress (2014) reducesTemperature Variability enhances
Recovery returns reefs to normal.Keep algae low (many herbivores, low nutrients)Promote coral growth/reproduction
Exposure triggers bleaching impacts.Temperatures Above Threshold High LightShallow waters
Resistance limits exposure’s damage.Sewage reducesPrevious thermal stress (2014) reducesTemperature Variability enhances
Recovery returns reefs to normal.Keep algae low (many herbivores, low nutrients)Promote coral growth/reproduction
Exposure triggers bleaching impacts.Temperatures Above Threshold High LightShallow waters
Resistance limits exposure’s damage.Sewage reducesPrevious thermal stress (2014) reducesTemperature Variability enhances
Recovery returns reefs to normal.Keep algae low (many herbivores, low nutrients)Promote coral growth/reproduction
Exposure triggers bleaching impacts.Temperatures Above Threshold High LightShallow waters
Resistance limits exposure’s damage.Sewage reducesPrevious thermal stress (2014) reducesTemperature Variability enhances
Recovery returns reefs to normal.Keep algae low (many herbivores, low nutrients)Promote coral growth/reproduction
Analysis and Ranking ofEcological Effectivenessof the 22 most promising management actions to promote coral ecosystem recovery after bleaching impacts, based on:
1. Global Expert Survey2. Hawaiʻi Workshop3. Literature Review