engleski

Variations in Posidonia oceanica meadow characteristics along a large enclosed bay within a protected area on the Eastern Coast of the Adriatic Sea

In the Mediterranean, the seagrass Posidonia oceanica (L.) Delile is considered highly threatened and therefore holds habitat priority status under Natura 2000. Because the extent and health of Posidonia in the Croatian Adriatic is currently unknown, we conducted several studies of its distribution and basic characteristics along the shoreline of 10-km long enclosed bay within Telascica Nature Park. There are no permanent human settlements along its coast so the human impact can be perceived as small. We sampled 21 stations from 2002 to 2006 in and near the bay, and Posidonia beds were noted at 11. At all Posidonia stations the lower depth limit of the meadow was measured as well as shoot density at several fixed depths. At 3 stations, shoot samples were taken along a depth gradient for analysis of leaf morphology and lepidochronology, light intensity was measured, and biomass and primary production were estimated. Differences in Posidonia distribution throughout the bay and consistent variation in its bathymetric range can probably be attributed to natural eutrophication in inner parts of the bay. Also, differences were noted among sampled stations in shoot density, leaf area index, biomass and estimated annual primary production as well as along the depth gradient within each station. Results are compared with published data for Mediterranean Posidonia beds.

Posidonia oceanica; vertical and horizontal distribution; Nature Park Telašćica; Croatia

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