Coral reef restoration methods are showing promising results in supporting regional efforts for restoring degraded coral reefs in the Dutch Caribbean. Therefore, the Dutch Caribbean Nature Alliance (DCNA) organizes a reef restoration workshop led by University of Applied Sciences Van Hall Larenstein (VHL) between April 5th and 6th on Saba. This workshop will involve coral reef biologists, coral restoration experts, and marine park managers from various Caribbean islands to focus for the first time on the restoration of one important key player on the reef – Diadema antillarum, – long-spined sea urchin.
Importance of Diadema Sea Urchins
Healthy coral reefs are essential as they are a magnet for tourists and at the same time one of the most important sources of income for the Dutch Caribbean. Long-spined Sea urchins (scientific name Diadema antillarum) play a critical role in maintaining healthy coral reefs. They help sustain the delicate balance within the reef by grazing on algae, which are the main competitors of corals. Unfortunately, in the mid-1980s, a disease swept through the Caribbean, wiping out nearly the entire sea urchin population. Soon after, reports of rapid algae growth were documented throughout the Caribbean. The algae occupy all available space, preventing coral recruitment and limiting the coral reef’s ability to recover from other disturbances. So far, recovery of D. antillarum populations has been very slow to nonexistent. In the few areas where sea urchins were able to naturally recover, these trends were reversed, highlighting the importance of restoring this keystone species.
In the RAAK Pro Diadema project VHL works closely together with other research institutes and local partners to restore long-spined sea urchin populations on the coral reefs around Saba and St. Eustatius. This project is showing promising results. The lead researchers Alwin Hylkema and Tom Wijers will share their impressive tools, techniques, and latest scientific findings to facilitate the restoration of Diadema in the Wider Caribbean region during the DCNA workshop.
The workshop will concentrate on the historical context and status of these reduced herbivores and introduce Diadema restoration techniques that have shown promising results. Also on the agenda are hands-on training sessions, to improve practical skills related to Diadema restoration. There will also be attention for the recent Diadema die-off events in the Caribbean and an update on the latest findings. Some sessions will be possible to follow live online for people working in this field who are unable to attend in person.
During the days, there will be intense dialogue between islands to exchange local knowledge, share expertise, stimulate cooperation where suitable and unveil the necessary tools to mitigate the loss of Diadema sea urchins.
Game Changer in Reef Restoration
Coral reef restoration in the Dutch Caribbean has focused heavily on corals. This workshop is built upon research and innovation that introduces the restoration of the important algae grazer Diadema. By restoring reef grazers alongside corals, the corals will have a higher chance to survive. The long-spined sea urchins graze away the algae, which are important competitors of the corals. By creating bare substrate, the sea-urchins can also facilitate natural coral recruitment.
Safeguarding Coral Reefs
DCNA strives to safeguard nature, including its extraordinary coral reefs in the Dutch Caribbean. Significant local threats that need to be tackled to safeguard the reefs include poorly regulated (coastal) development, wastewater, and waste management as well as overgrazing. Also, the lack of sustainable funding and policy support hamper conservation management.
On top of this, is coral reef restoration an important component. Both coral and Diadema sea-urchin restoration can assist in saving the important but fragile coral reefs and make them more resilient to the impacts of climate change.
This workshop is generously funded by the Ministry of Agriculture, Nature and Food Quality (LNV) as a support to the Nature and Environmental Policy Plan for the BES-islands, the Dutch Postcode Lottery and SIA, part of the Dutch Research Council (NWO).