Slow but steady progress for seagrass restoration project
Efforts to restore the island’s seagrass beds have made slow but steady progress, according to new report.
According to the winter edition of the Department of Environment and Natural Resource’s (DENR) Envirotalk newsletter, measures to protect seagrass from grazing turtles has allowed them to start to recover.
But the Marine Conservation Section (MCS) of the DENR said that more work must still be done to ensure seagrass environments survive in the long-term.
The MCS said: “So far, there have been mixed results with some areas recovering more quickly than others but this is not unexpected because seagrasses, particularly turtle grass, are slow growing and can take five years or longer to fully recover.
“The seagrass habitat at some of the restoration areas was severely degraded – the turtle grass leaves were very narrow and had been grazed to less than one centimetre.
“The horizontal stems were exposed because the seagrass meadow could no longer perform one of its functions which is to hold the sediment in place. These areas are likely to take much longer to regenerate.”
Last year, several initiatives were announced to safeguard the island’s seagrasses, which had been hard hit by a growing number of juvenile green turtles visiting the island.
In September 2020, DENR partnered with the West End Development Corporation to block turtles from the lagoon on Ireland Island to help the seagrass in the area bounce back.
The newsletter said that as of last month the work had begun to bear fruit.
The MCS said: “While the seagrass in the lagoon has to grow a lot more to become the dense meadow it was in 2017 before the turtles began to feed on it, it is beginning to recover now the turtle grazing pressure has been removed.
“Our surveys show that the seagrass is still sparse throughout the lagoon, but in some areas where there were a few shoots of seagrass in 2020, particularly manatee grass, the seagrass has grown and developed into much denser patches, which is extremely encouraging.”
The newsletter also said the MCS sought to protect other areas of seagrass by installing mesh cages over them to limit turtle grazing.
The MCS said: “The cages protect the seagrass from further grazing. This allows the seagrasses to regenerate, albeit slowly, and with time some of the essential ecosystem functions they provide will be restored.
“Even with the cages, the turtles are always able to graze around the inside edges.
“Once the seagrass leaves are long enough, turtles are able to feed on them through the top of the cage, but this still allows enough seagrass to provide shelter for other organisms.”
“Eventually, when the balance of Bermuda’s marine ecosystem is restored to where we have healthy populations of turtle predators, especially sharks, the seagrasses in these caged areas will grow out from under the cages to independently colonise seabed areas that are environmentally suitable for seagrasses.”
The MCS reported that in some areas, seagrass outside of the cages had been able to bounce back as quickly as that inside, but it also noted that there had anecdotally been fewer turtles seen in Bermuda’s waters.
The MCS said: “In locations where there are still some remnants of seagrass habitat surviving and currently no turtles frequenting that particular area to eat it, the seagrass is beginning to recover whether it is protected by cages, or not.
“However, new juvenile green turtles will continue to arrive on the Bermuda platform as a result of successful conservation efforts on nesting beaches to our south and be looking for seagrass to eat.
“It is just a question of whether the newly arrived green turtles will stay and eat every last blade of seagrass they can find or leave quickly because seagrass is difficult to find.”
The MCS said the seagrass cages would be needed for the foreseeable future to ensure the seagrass survived and could continue to provide shelter for species such as fish, lobsters, seahorses and juvenile queen conch.
They added: “When the balance in our marine ecosystem is restored and the green turtles and seagrass can coexist, the seagrass restoration cages can be removed.”