Page 37 - Livre_MOW2024_EN

IN
FIGURES

Posidonia meadows :
1
■ are home to over 400 species of plants and 1,000 species of marine
animals,
■ protect beaches by reducing wave energy by 20%,
■ limit coastal erosion,
■ sequester 5 tons of carbon per hectare per year: the carbon stocks held
in dead meadows are 10 times higher than those found in forest soils.

A highly valuable resource:
Seagrass meadows are worth 50,000 euros per hectare per year, which is
3 times more than coral reefs and 10 times more than rainforests. 2

Seagrass beds in French Mediterranean waters cover 80,000 hectares,
10% of which are dead meadows that store carbon. Across the
Mediterranean as a whole, Posidonia covers more than 2 million hectares,
900,000 of which are in Tunisia. 3
1. C F Boudouresque et al, Protection and Conservation of Posidonia Oceanica Meadows
(Tunis: RAMOGE and SPA/RAC, 2012, 1–202).
2. Robert Costanza et al, ‘The Value of the World’s Ecosystem Services and Natural Capital’, Nature (1997).
3. Data calculated using ESRI ArcGIS©, in Luca Telesca et al, ‘Seagrass meadows (Posidonia oceanica)
distribution and trajectories of change’, Scientific Reports (5, 12505, 2015) and ‘MAPAMED, the database of
marine protected areas in the Mediterranean’ (MedPAN & SPA/RAC, 2021).

PROFILE

Posidonia oceanica
meadows are an emblematic
habitat found exclusively
in the Mediterranean sea,
where they can be likened to
the Amazon rainforest for the
role they play. Protected in
France since 1976, and now
in Europe and internationally,
this seagrass species acts
as a vital habitat for marine
life and provides nursery
grounds for fish populations.

- Underwater photo showing the impact of yachting on Posidonia meadows -
© Laurent Ballesta / Andromède Océanologie