SINT MAARTEN (SIMPSON BAY) – On Sunday, 26 July, Environmental Protection in the Caribbean (EPIC) began the removal of PVC pipes installed to protect mangrove seedlings planted in Simpson Bay Lagoon after hurricane Irma. With the help of volunteers and Sint Maarten Sails, which provided a boat, half the 300 pipes were removed, allowing the new red mangrove trees to spread their distinctive prop roots and develop further.
During Irma, an estimated 80% of mangroves were damaged as the eye of the category 5 hurricane passed over Sint Maarten on 5 September 2017. At the time, EPIC had a grant from BEST 2.0 (Biodiversity and Ecosystem Services in Overseas Countries and Territories, funded by the European Union) to restore coastal and terrestrial biodiversity by planting native plant species. This included coastal mangrove wetlands with the focus on the replanting of 300 red mangroves in Simpson Bay Lagoon.
In November and December 2017, red mangrove seedlings (known as propagules) were planted using the Riley Encased Method (REM), a method developed to establish mangroves along high-energy shorelines where natural recruitment is limited. The principles of REM are based on isolating individual propagules from the external environment, i.e. in tubular encasements, creating an artificial environment favorable to early plant development: plants are protected from wrack, debris, wind, wave activity, and unintentional damage from human interaction.
For the EPIC mangrove replanting in Simpson Bay, PVC plastic tubes were used. Volunteers of all ages helped hammer the tubes into the seabed and partially fill them with mud. The tubes were then left to settle for a few hours to avoid air pockets, then one propagule was dropped into each tube. EPIC tested two methods of PVC tubing 1) a single tube of 1m cut lengthwise and 2) two 0.5m tubes joined with a PVC coupling joint. In the first, the tubing is manually broken apart as the mangrove grows beyond the pipe’s confines. With the second, the upper piece of piping is removed.
Early 2018, EPIC conducted monitoring of the mangroves, measuring the size of the new tree stem and counting leaf growth to assess success of restoration efforts. At this stage, the new mangrove trees were only a few centimeters tall, but all indications were that a new mangrove forest was developing well. More recently, EPIC was able to begin the removal of the PVC pipes now that the mangroves are strong, have started developing their prop roots and no longer need the protection. The remainder of the tubes will be removed after the hurricane season.
A final count of the new mangrove trees will be made when all the pipes are removed. Current estimates are that over 70% of the original propagules are now flourishing mangrove trees of between 1m and 1.5m in height; this is a great result as early studies of REM replanting have generated 60-70% average success rates.
Mangroves are an important part of the ecosystem and are sadly less abundant in Sint Maarten than in previous years due to major hurricanes like Irma, but also as a result of destruction to make way for development. Mangrove forests have an enormous capacity for sequestering carbon dioxide. They store more carbon per unit area than terrestrial forests, including the Amazon, and are now being recognised for their role in mitigating climate change. Here in Sint Maarten, in 2016, Mullet Pond was designated a Ramsar wetland site, recognised internationally as a site of the nationally critically endangered buttonwood mangrove and an important habitat for juvenile fish species which develop in Simpson Bay Lagoon. However, whilst Mullet Pond’s mangroves are recognised internationally, they are yet to be protected in law.
In a recent educational session about mangroves at a summer camp, one young participant summed it up when she wrote her thoughts on green paper cut in a mangrove leaf shape, “Mangroves are the best. It saves us. Protect the mangroves now.”
Campers at St. Maarten Yacht Club with the mangrove tree they crafted to demonstrate the many service these trees provide. Credit: Janet Robertson
The prop root of a red mangrove seedlings emerges from a crack in the pvc pipe which protected it until it rooted. Credit: Ildiko Gilders