| Abstract: | - 1. The status of a Posidonia oceanica meadow in front of the town of Sanremo, Italy, was studied through a combined use of benthic mapping and synthetic indices.
- 2. Mapping was accomplished by integrating side scan sonar imagery and data collected by scuba diving along transects placed perpendicularly to the coastline. A thematic map (scale 1:5000) was produced. Extent of the meadow, occurrence of dead matte areas, and morphology of the lower limit (with new definition) are all described.
- 3. Two synthetic environmental indices were applied to transect data in order to quantify the status of the meadow: the Conservation Index and the Substitution Index. The former is related to the proportion of dead matte; the latter is a novel index measuring the amount of replacement of the ‘constructional’ seagrass P. oceanica by the ‘non‐constructional’ seagrass Cymodocea nodosa. The potential of a ‘phase shift’ in Ligurian Sea seagrass meadows is discussed.
- 4. The approach here proposed, based on detailed mapping plus synthetic indices, may provide immediate information to evaluate the state of Mediterranean Posidonia oceanica for monitoring and management.
Copyright © 2006 John Wiley & Sons, Ltd. |
