Distribution and estimation of basal area coverage of subtidal seagrass meadows in a Mediterranean coastal lagoon

The surface area covered by three protected seagrass species (Cymodocea nodosa, Zostera noltii and Ruppia cirrhosa) and their distribution in the Urbinu Lagoon were estimated for the first time by surveying 206 ha area, representing 29% of the total area, using field data, aerial photography and image processing. These methods allowed evaluation of the distribution of seagrass meadows both at horizontal and vertical levels. The computer analyses of the cartographic data permitted evaluation of the surface occupied by the various types of populations. The identification of the limiting factors, which may affect the quality of results, allows the proposal of a scale of reliability for the estuarine ecosystem.