By Mike Gaworecki from Mongabay

It’s not just the Great Barrier Reef — coral reefs around the globe are in decline due to climate change, ocean pollution, and a number of other impacts of human activities on marine environments.

But new research finds that “coral gardening,” which involves planting fragments of nursery-raised coral on reefs in the wild to replenish depleted coral colonies, is playing a key role in the restoration of staghorn coral reef systems in the Caribbean — and might just help inform strategies to ensure the long-term survival of the world’s coral reefs in the future.

A study published in the journal Coral Reefs in June looks at how successful restoration efforts have been at several sites in Florida and Puerto Rico over the first two years of a staghorn coral (Acropora cervicornis) gardening program. The researchers behind the study — a team led by scientists with the Rosenstiel School of Marine and Atmospheric Science at the University of Miami (UM) — say they found that current restoration methods do not cause excessive damage to donor colonies (from which coral tissue is taken and propagated in a nursery), and that once the coral fragments are planted back out in the wild, known as being “outplanted,” they behave just like wild colonies.

Particularly susceptible to bleaching, staghorn coral populations have declined more than 80 percent over the past 30 years due to higher incidence of disease and the impacts of global warming, especially higher ocean temperatures and ocean acidification, according to theInternational Union for the Conservation of Nature (IUCN). The species was listed as threatened under the U.S. Endangered Species Act in 2006 and is currently listed as Critically Endangered on the IUCN Red List.

There have been efforts to propagate and reintroduce A. cervicornis in waters near the Dominican Republic, Florida, Honduras, Jamaica, and Puerto Rico, the IUCN reports.

“Coral reefs are declining at an alarming rate and coral restoration programs are now considered an essential component to coral conservation and management [planning],” Diego Lirman, a professor of marine biology and ecology at UM and co-author of the study, said in a statement.

Lirman and the rest of the team collected data on the survival and productivity of thousands of individual A. cervicornis colonies within six different geographical regions in order to develop benchmarks that can be used to assess coral reef restoration efforts and their impacts on the overall ecosystem. “Our findings provide the necessary scientific benchmarks to evaluate restoration progress moving forward,” Lirman added.

“We propose that up to 10% of the biomass can be collected from healthy, large A. cervicornisdonor colonies for nursery propagation,” the researchers write in the study. They also propose a number of benchmarks for the first year of staghorn coral restoration efforts: greater than 75 percent live tissue cover remaining on donor colonies; greater than 80 percent survival of nursery corals; and greater than 70 percent survival of outplanted corals.

The world’s wild coral reef systems provide habitat for fisheries, supply food for humans and numerous marine species, and help protect shorelines against hurricanes and other extreme weather events. That’s why coral restoration is coming to be seen as an effective means of ensuring coral reef systems are still capable of providing those ecosystem services as well as for mitigating the impacts of rising sea levels and storm surges on coastlines, according to UM coral biologist Stephanie Schopmeyer, lead author of the study.

“Our study showed that current restoration methods are very effective,” Schopmeyer said in astatement. “Healthy coral reefs are essential to our everyday life and successful coral restoration has been proven as a recovery tool for lost coastal resources.”

CITATIONS

• Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil. 2008. Acropora cervicornis. The IUCN Red List of Threatened Species 2008: e.T133381A3716457.http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T133381A3716457.en. Downloaded on 08 August 2017.
• Schopmeyer, S. A., Lirman, D., Bartels, E., Gilliam, D. S., Goergen, E. A., Griffin, S. P., … & Walter, C. S. (2017). Regional restoration benchmarks for Acropora cervicornis. Coral Reefs, 1-11.doi:10.1007/s00338-017-1596-3

IMAGES:

Staghorn coral. Photo via Wikimedia Commons.

Staghorn corals (Acropora cervicornis) are propagated within underwater coral nurseries to create a sustainable source of corals for use in coral restoration activities (inset). Outplanted corals have similar survival and productivity values as wild colonies, thereby indicating that coral gardening methodologies are successful in creating healthy corals for restoration. Photo Credit: Stephanie Schopmeyer, UM Rosenstiel School of Marine and Atmospheric Science.

For more on this story go to: https://news.mongabay.com/2017/08/critically-endangered-staghorn-corals-are-benefiting-from-coral-gardening-in-the-caribbean/