Biomonitoring of Posidonia oceanica beds by a multiscale approach

In this study a multiscale biomonitoring approach, which encompasses multiple levels of observations (from ultra- to meso- and macroscale, photo mosaicing and SRS), was applied to evaluate the conservation status of a P. oceanica meadow. In particular, the approach included a combination of molecular and biochemical parameters associated to the assessment of plant phenology and large-spatial bed structure and heterogeneity, which have ecological relevance. The aim was to identify a toolbox of reliable and economically feasible indicators to efficiently monitor and manage seagrass meadows. At ultrascale level, the OJIP-test, a screening test based on the quantitative analysis of the chlorophyll a fluorescence, was used for the first time on P. oceanica. At molecular level we tested the expression pattern of a panel of genes involved in the stress and photosynthesis pathways, as fast and sensitive response to stress exposure. At the microscale level, phenological features of P. oceanica were considered; at mesoscale level, the morphology of the meadow was determined by a photomosaicing technique. Finally, at a macroscale level, a spatially extensive map was produced by Remote Sensing approach. An anticipatory signal of pressure impending on the P. oceanica meadows was provided by molecular and biochemical markers, thus confirming the importance of a multiscale approach to asses a risk conditions in a natural environment, before these have a long-term effect.