RTL Today – “Neptune grass”: Forgotten but essential: experts call for the protection of seagrass beds
While the largest global biodiversity summit is due to open on Friday in the Mediterranean city of Marseille, experts are sounding the alarm on long neglected herbaria increasingly threatened by human activity.
Named posidonia oceanica – or “Neptune’s grass” – for the Greek god of the seas, the plant covers at least one million hectares (3,900 square miles) of the Mediterranean seabed from Cyprus to Spain.
The Mediterranean Posidonia Network says the actual area is likely much larger than this, with data largely unavailable for countries on the eastern and southern shores of the sea.
But the meadows of neptune grass have long been the prey of nautical activity, official figures estimating some 7,500 hectares of damage along the French coast alone.
“The biggest culprit is mooring,” explains Thibault Lavernhe, spokesperson for the Maritime Prefecture of the Mediterranean.
“When a ship drops anchor, it hits the bottom of the ocean and has a devastating effect … which is repeated when the anchor is raised.”
Since algae grows slowly – only a few inches each year – the impact can take a long time to repair.
In an open letter published this month in the French daily Le Monde, 10 scientists from France, Italy and Spain stressed the essential services that humble herbaria provide “to all humanity”.
“Seagrass beds serve as spawning grounds and nurseries for species of fish living along our coasts, from the most common to the rarest,” they wrote.
A wide variety of animals depend on it, including tiny invertebrates that are a food source for fish prized by small-scale artisanal fishing operations.
Arnaud Gauffier, conservation director of the French branch of the World Wide Fund for Nature (WWF), affirms that the plant’s capacity to absorb carbon makes it an essential ally in the fight against global warming.
And he says plants protect shorelines from erosion – both when they’re firmly rooted to the seabed and when they wash up on the shore.
Dead blades of grass accumulate along the beaches and mix with the sand to form large banks that protect the coastline.
But for some, the phenomenon is only an unsightly inconvenience.
“Unfortunately, the ecosystem is poorly understood,” says Gauffier.
“A lot of times people just think, ‘Oh no, it’s a dead thing on the beach that’s preventing me from swimming.'”
In order to combat damage to Mediterranean seagrass beds, France has banned large boats – measuring over 24 meters (79 feet) – from anchoring in sensitive areas.
The Spanish Balearic Islands took similar measures in 2018 and enforce them with regular patrols.
Their conservation efforts, which include awareness campaigns in schools and a herbarium festival, have been highlighted as exemplary by WWF.