POSIDONIA OCEANICA MIMICS AS AN EXPERIMENTAL TOOL TO STUDY COLONIZATION OF SEAGRASS EPIPHYTES. AN EXAMPLE ALONG A GRADIENT OF WATER ACIDIFICATION FASCI ARTIFICIALI DI POSIDONIA OCEANICA PER LO STUDIO DELLA COLONIZZAZIONE DEGLI EPIFITI. UN ESEMPIO LUNGO UN GRADIENTE DI ACIDIFICAZIONE DELLE ACQUE

Mimics of Posidonia oceanica shoots are here described for the experimental study of epiphyte colonization in this plant. The mimic rhizome consists of a hollow cylinder made of earthenware (3 cm diameter × 13 cm length) and for the leaves, 4 stripes of flexible PVC (1 cm × 36 cm) of a dark green color and attached to a hooked iron stake. Preliminary results on epiphyte colonization in Posidonia meadows along a gradient of water acidification, confirm that mimics well reproduce the microclimatic conditions of the Posidonia shoots, with leaves showing a reduced diversity and higher patchiness than rhizome mimics, as observed in natural Posidonia shoots.