CaRe-GR combines remote sensing, scientific diving, artificial intelligence and ecosystem-based assessment into a single, standardised workflow. The methods and protocols below underpin every work package, from national-scale mapping to restoration prioritization.
Remote sensing & mapping
Shallow reefs and macroalgal forests are mapped nationally from Copernicus Sentinel-2 imagery (10 m resolution) processed with ACOLITE aquatic reflectance and machine-learning regressions and spectral unmixing. Deep reefs (coralligenous formations, rhodolith beds) and the country’s 700+ marine caves are compiled through systematic reviews of scientific and grey literature, databases and expert knowledge, and integrated into national GIS layers and spatial databases.
Reef field surveys — ECOfast
Rocky reefs are evaluated at 100 or more sites using the rapid visual index ECOfast, together with its invasive-species variant ECOfast-NIS. Standardised photoquadrat sampling collects more than 10,000 images across distinct bathymetric zones (0–1 m, 5 m and 15 m), recording macroalgae, fish, invertebrates, substrate types and non-indigenous species.
Marine cave surveys
Marine caves are surveyed non-destructively by SCUBA divers across three ecological zones — entrance, semi-dark and dark. Visual censuses of motile fauna are combined with structural photoquadrats of sessile communities (sponges, bryozoans, ascidians, hydroids and anthozoans), alongside documentation of pressures and threats such as alien species, necrosis and marine litter.
AI-supported image analysis
Photoquadrats are processed through deep neural networks via CoralNet to automate morphofunctional benthic-coverage estimation. Cave images are first classified manually with photoQuad software, which in turn trains CoralNet for automated cave-image annotation, improving the efficiency and consistency of large-scale assessments.
Ecological quality indices
- reef-EBQI — ecosystem-based quality index used to verify and map the ecological status of rocky reefs.
- CavEBQI — ecosystem-based quality index for marine caves, adapted for the eastern Mediterranean.
- ECOfast / ECOfast-NIS — rapid visual assessment of reef condition and non-indigenous species.
Restoration prioritization
A global systematic review of reef and cave restoration metrics informs field-scale pilots testing combined interventions (for example sea-urchin culling, invasive-fish control and canopy-algae transplantation). Biodiversity, status, cost and connectivity layers feed the conservation-planning tools prioritizr and restoptr to generate a spatially explicit, optimised national restoration strategy.
Citizen science
Through the “Cscience4all – diving” initiative, CaRe-GR trains volunteer divers, oceanography graduates and regional stakeholders in standardised reef-monitoring protocols, expanding data collection across the Greek seas and building long-term monitoring networks.