Posidonia Habitat Mapping: Spetses & Velopoula
THE CHALLENGE
Posidonia oceanica meadows, often described as the “forests of the sea”, are among the Mediterranean’s most valuable ecosystems. They store blue carbon, stabilise coastlines and provide nursery grounds for hundreds of marine species.
In the Argosaronic, these meadows are under increasing cumulative pressure from intense anchoring, dense boat traffic, tourism-related coastal development, and uncoordinated aquaculture spatial planning. Despite their ecological and economic importance, the true extent and condition of Posidonia meadows around Spetses and the neighbouring island of Velopoula had never been systematically mapped.
Without accurate spatial data, anchoring management, marine zoning, protection considerations and conservation planning remain severely constrained.
THE PROJECT
With AEF’s support, iSea carried out the first detailed site-specific mapping of Posidonia meadows around Spetses and the uninhabited island of Velopoula.
The project combined:
- High-resolution satellite imagery to identify potential seagrass distribution
- Diver, drone and ROV field validation to calibrate and verify data
- Advanced classification modelling to ensure high mapping accuracy
- Habitat analysis extending beyond 30m depth
This integrated methodology produced robust, high-confidence distribution maps suitable for informing marine spatial planning, anchorage management and future conservation interventions.
OUTCOMES
The project was completed according to plan, successfully delivering detailed Posidonia maps for both Spetses and Velopoula.
Impact at a Glance
- 4.1 km² of Posidonia meadows mapped providing the first comprehensive spatial assessment in the area
- Velopoula meadows documented as 11 times larger than previously recorded in Natura 2000 datasets
- 90% mapping accuracy achieved
- Creation of a reliable baseline for anchoring regulation and zoning discussions
- Strengthened scientific understanding of the area’s blue carbon capacity and biodiversity value
RELATED
- Ongoing
- Completed
- Completed
- Completed
- Completed
- Completed
