Monitoring the Posidonia Meadows structure through underwater photogrammetry: a case study

The Posidonia oceanica meadows represent a fundamental biological indicator for the assessment of the marine ecosystem state of health. They also cover an essential role in the conservation of coastal morphology. The composition, extent and structure of the meadows are conditioned by the biological characteristics of the plant itself and by the environment setting, considering the type and nature of the substrate, the geomorphology of the seabed, the hydrodynamics, depth and brightness of the scenario, the sedimentation speed, etc. In this work we present a methodology for the effective monitoring and mapping of the Posidonia oceanica meadows by means of underwater photogrammetry: the analysis made on their structure is further intended to verify the possibility of using the photogrammetry for the reliable characterization of the seabed and the classification of the vegetation coverage.