go to main content
News

News

Print (Open in new window) PrintForward (Open in new window) Forward
Text size:

Add to Google Bookmarks (Open in new window)Share on Facebook (Open in new window)Share on Twitter (Open in new window)Share on Line (Open in new window)

Studies by scholars and staff at the Dongsha Administration Station have found that, while the growth of coral reefs are thriving on the exterior of the Dongsha Atoll, the coral reef ecology in the atoll's lagoons have not yet recovered from the abnormally high global ocean temperatures of 1998. It was found that reef rocks formed a barrier that prevented the exchange of seawater between the lagoon and the outer ocean, resulting in the heating of seawater by increased exposure to sunlight during summer seasons and affecting the naturally restoring capacities of the coral reefs. Studies have also found that while organisms are slowly recovering in the lagoon, the overall balance of the coral reef ecosystem was affected by the slow recovery of the coral reefs. Currently, S-type (stress-tolerator) corals have become the dominant coral populations in the lagoon, while ruderals (R-type corals), important habitats for young marine animals, are rarely seen.

R-type corals at Dongsha Atoll are mainly Acroporas. Recent studies have shown that, compared with the gradual restoration of the K and S type corals, the recruitment of R-type small Acroporas are significantly less. This may be due to the deficiency of the Dongsha marine macro-environment. Acroporas are fast growing and are much more sensitive to the changes of the environment than other corals; overly high water temperature, turbidity and changes in salinity may result in bleaching and deaths of Acropora corals. Since the 3-dimensional branching structures of Acroporas provide excellent sanctuaries for the many coral reef fish species and contribute to the restoration of fish and invertebrate biological resources, restoration of Acroporas is currently the most pertinent target of coral reef restoration.

The best side of the Dongsha Atoll is during calm winds and smooth waves.
The best side of the Dongsha Atollis during calm
winds and smooth waves.
The abundant and thriving coral reef ecosystems on the exterior reefs on the Dongsha Atoll.
The abundant and thriving coral reef ecosystems
on the exterior reefs on the Dongsha Atoll.

After long-term investigations and experiments, conservation staff has found heat-resistant acropora species near the Dongsha Islands and has been using them as parental stocks for coral restoration. Exploiting the asexual reproduction advantage of corals, researchers have performed branch-grafts directly on corals in the ocean, as well as locating suitable breeding grounds in different environments by performing breeding experiments on different substrates. Researchers have currently designated two areas for the branching and stock restoration of corals, which are located at the northern shore of Dongsha Island in depths of 100 and 500 meters.

The Dongsha Island Wildlife Conservation Center, completed at the beginning of this year, is also an important site for coral restoration effort. Researchers transport the heat-resistant Acropora species that have shown excellent growth conditions in the northern shores of Dongsha Island back into the center for a second branching operation. Corals are temporarily housed in restoration tanks and once the cut sites have healed, are moved to the coral patches in the atoll lagoon for better survival. The purpose of the grafts is to increase the density of Acropora corals in the lagoons. It is hoped that once the corals have grown into larger populations, they may conduct sexual reproductions and increase their recruitment naturally, restoring the balance of the coral reef ecosystem.

The s-type corals dominate the lagoon now; all that’s left of the once abundant Acroporas are skeletons.
The s-type corals dominate the lagoon now; all
that’sleft of the once abundant Acroporas are
skeletons.
 
 
Acroporas found at the northern shore of the Dongsha Island are still resistant to the average water temperature of 30℃ during the summer seasons of July and August, and are good candidates for restoration grafts.
Acroporas found at the northern shore of the
Dongsha Island are still resistant to the average
water temperature of 30 during the summer
seasons of July and August, and are good candidates
for restoration grafts.

*Note:

R-type (ruderals, R) corals:
Fast growing and suitable for habitats with frequent environment disturbances, such as Acroporas, Milleporida and Heliopora.

K-type (competitors, K) corals:

Species that are environmentally competitive, mostly leaf-like or branch-like non-Acropora species, smoother in appearance and have smaller populations, such as the leaf-like Montipora, branch like Porites and free-form Fungia.

S-type (stress-tolerators, S) corals:
These are stress-resistant species that grow slowly but high resistant to adverse environments, such as blocky Porites,
Galaxea and Goniopora.
When s-type corals dominate the environment, the spatial complexity and live-coral coverage are lower, the ratio of dead corals to live corals is higher, the biodiversity index is lower, and the conservation level is also lower. When there are equal amounts of coral species of all types, the biodiversity and terrain complexity are higher, and the level of conservation is also higher.

The ocean is my lab: Researchers perform coral branching breeding directly in the ocean.
The ocean is my lab: Researchers perform coral
branching breeding directly in the ocean.
Fragments of coral branches
Fragments of coral branches
 
After nearly a year of growth, the Acroporas flourishes rapidly
After nearly a year of growth, the Acroporas
flourishes rapidly
The newly completed Wildlife Conservation Center at the Dongsha Island
The newly completed Wildlife Conservation
enter at the Dongsha Island
Performing coral branching and breeding work in the Conservation Center
Performing coral branching and breeding work in
the Conservation Center
In an indoor, controlled environment, corals may be bred in high density and will have better survival rates than in the wild. Once the cut sites from the branching operations have healed, the corals are returned to the wild for higher survival rates.
In an indoor, controlled environment, corals may be
bred in high density and will have better survival
rates than in the wild. Once the cut sites from the
branching operations have healed, the corals are
returned to the wild for higher survival rates.
Back

footer