11th ICRS Abstract book - Nova Southeastern University

12-23
Coral Reef Resilience To Chronic And Acute Disturbances: Lessons From 90 Years
Of Monitoring in American Samoa
Alison GREEN* 1 , Charles BIRKELAND 2 , Douglas FENNER 3 , Cheryl SQUAIR 4
1 The Nature Conservancy, Australia, Brisbane, Australia, 2 Hawaii Cooperative Fishery
Research Unit, USGS, USA, Honolulu, HI, 3 Dept of Marine and Wildlife Resources,
American Samoa, Pago Pago, American Samoa, 4 University of Hawaii, USA, Honolulu,
American Samoa
In 1917, Alfred Mayor established a quantitative coral transect on the reef flat at Aua in
Pago Pago Harbor, American Samoa. He recorded rich coral communities in distinct
zones along the transect. In the 1950s-1980s, this area was seriously degraded by chronic
pollution from two tuna canneries in the inner harbor and by coastal development. By the
1970s, coral communities had declined substantially, and there was a change in the
relative abundance of coral genera and major changes in coral zonation. In 1992, a large
pipe was installed to export wastewater from the tuna canneries to the harbor mouth.
Since then, there has been a significant recovery of coral communities on the reef crest
and outer reef flat where there is consolidated reef substratum (up to 30 m back from the
reef crest). In contrast, recovery has been substantially slower behind the reef crest,
where the substratum is primarily loose rubble. In particular, the Acropora zone recorded
on the outer reef flat in 1917 (120-140m behind the reef crest) had disappeared
completely by the 1990s. Recovery is now proceeding in this zone by the slow
accumulation of Acropora formosa colonies that are large enough to become established
on the loose substratum. This study demonstrates different rates of recovery after chronic
disturbance due to the influence of substratum type. This is in contrast to the results of
long term monitoring in Fagatele Bay National Marine Sanctuary west of the harbor
(since the late 1970s), where reefs have been shown to recover from acute disturbances
such as hurricanes within 10-15 years. Major differences in rates of recovery appear to
be the result of different types of disturbance (acute vs chronic), and degree of substratum
consolidation.
12-24
What Is The Future For Extensive Areas Of Reef Impacted By Fish Blasting And
Coral Bleaching And Now Dominated By Soft Corals? A Case Study From
Malaysia.
Elizabeth WOOD* 1 , Frances DIPPER 2
1 Marine Conservation Society, Hook, United Kingdom, 2 Marine Conservation Society,
Ross-on -Wye, United Kingdom
Many reefs in the Tun Sakaran Marine Park, Sabah, East Malaysia have been damaged
by fish blasting and to a lesser extent by coral bleaching and crown-of-thorns starfish.
Coral communities that comprised a mixture of growth forms and included a greater
proportion of massive or robust species are recovering better than those where the
majority of corals were laminar and foliaceous. One particular problem is at clear-water
sites where there were extensive stands of laminar Montipora on the reef rim and upper
slope. Collapse of these colonies created rubble that typically became colonised by soft
corals, particularly xeniids. The xeniids are acting as a barrier to recruitment of hard
corals and provide no shelter or structural complexity, with the result that these areas are
now largely devoid of fish. The implications of this changed ecology for biodiversity,
reef growth and productivity are discussed.
Oral Mini-Symposium 12: Reef Resilience
12-25
Stability Of Reef Framework And Post Settlement Mortality As The Structuring Factor
For Recovery Of Malakal Bay Reef, Palau, Micronesia: 25 Years After A Severe COTS
outbreak.
Steven VICTOR 1 , Steven VICTOR* 1
1 Research, Palau International Coral Reef Center, Koror, Palau
Corals in Malakal Bay reefs were devastated in the 1979 Crown of Thorns Starfish (COTS)
outbreak. It has been almost 30 years since the outbreak and coral cover at the study sites have
not come close to the cover before the outbreak. A question is asked: what factors may
contribute to the slow recovery of these reefs: recruitment or post-settlement mortality? Two
habitat types within the reef systems were monitored using coral transplants to determine if
corals can survive in these environments and recruitment tiles to see if there are larvae coming
into the system. The study revealed that coral survivorship is high in the fore reef areas
compared to the reef channel slopes and that larvae is not a limiting factor to natural recovery.
Stability of the reef framework, i.e unstable rubble substrate, and possibly high post settlement
mortality, are the structuring factors that determine the recovery process in these reef systems
and possibly so for similar habitats in other reef systems throughout Palau.
12-26
Response And Adaptation To Climate Change Stress On Andros Island Reefs, Bahamas
Philip KRAMER* 1,2
1 The Nature Conservancy, Sugarloaf key, FL, 2 Marine Geology and Geophysics, Rosenstiel
School of Marine and Atmospheric Science, University of Miami, Miami
The coral reefs along Andros Island, Bahamas provide an ideal setting to examine reef
structural and functional response to climate change given that they have experienced minimal
human and natural disturbances such as hurricanes over the past century. Here we show how
key ecological processes of coral mortality, herbivory, and recruitment, and physical factors
such as wave energy and temperature have influenced recovery from 1998 and 2005 bleaching
events. Since 2002, twenty-nine fixed sites representing six coral reef types have been
monitored using Atlantic and Gulf Rapid Reef Assessment (AGRRA) methodology every two
years. This 6-year monitoring dataset has been augmented with baseline AGRRA data collected
in 1997-98 and a historic dataset of in-situ temperature data and video and photographic
monitoring data collected since the early 1970’s. Extensive losses during the 1997-98 coral
bleaching and disease event reduced coral cover on high relief fore reefs and reef crests from
34% down to 12%. Lingering diseases and additional temperature stress during 2005 further
reduced stony coral cover below 10% on many fore reefs, with losses greatest in the
Montastraea annularis complex. Coral recovery has been limited, observed mostly as regrowth
of coral tissue remnants rather than direct recruitment. Even on shallow reef crests where high
levels of herbivory and faster rates of coral growth occur, high predation and coral disease limit
coral recruitment and recovery. Physical environmental factors correlate with observed spatial
patterns of resistance to bleaching and disease events. Lagoonal patch reefs exposed to highly
variable temperature and light conditions and patch reef located within inland tidal channels and
associated blue holes showed minimal loss of stony corals compared to bank margin reefs.
These results suggest that both functional and environmental factors account for the observed
patterns in resistance and recovery.
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