Threats to Posidonia oceanica meadows

Photo A. Politis


In the last decades, since the 50s, the Posidonia oceanica meadows have undergone a considerable regression, in some cases equal to 90% of its original extension.

The causes are mainly due to anthropic factors, including:

  • pollution, which damages the grasslands through chemical substances or the high turbidity of the water;
  • trawling, which is forbidden in Posidonia meadows, is often carried out by causing serious damage, such as the eradication of entire plants and the destruction of the typical terraced formation called "matte" (consisting of interlaced remnants of roots, rhizomes and entangled sediment). Considering that the "matte" has a very slow growth, the damage is very serious;
  • the wild anchoring of boats directly on the Posidonia meadows, which causes serious damage by tearing leaves and rhizomes, but also whole plants.


Damages due to indiscriminate anchoring by boats are illustrated by the Interreg GIREPAM Project in this significant video.

The life of Posidonia oceanica

Why Posidonia oceanica is so important?