31/10/2003

ANNUNZIATA ESPOSITO, AURORA ULISSE, IVAN GUALA, MARIA CRISTINA BUIA

Abstract

Epiphyte summer assemblages of Posidonia oceanica leaves were analyzed at regional (Sardinia) and basin (Western Mediterranean Sea) scales. Along Sardinian coasts, species composition has been evaluated at different sides (East and West), depths (5 and 25 m), and geographical sectors (North, Central—North, Central-South and South), in a total of32 sites. Deriving data from literature, ?ve localities at the same depth were compared, at basin scale. The community structure, at both taxonomic and biogeographic level. was analyzed to reveal spatial patterns in epiphyte assemblages. At smaller scale, the number of species varied signi?cantly with side, sector and site, while the assemblage composition did not; the biogeographic composition did not show significant differences because of the relevant in?uence of Subcosmopolitan and Cosmopolitan taxa. At basin scale taxonomic and biogeographic composition of epiphyte communities did not change according to a latitudinal gradient at least dealing with Western central Mediterranean Sea.

Biogeographia 24