Proceedings of the Second Mediterranean Symposium on Marine

While <strong>the</strong> <strong>Mediterranean</strong> Sea only represents less than 0.8% <strong>of</strong> <strong>the</strong> total area <strong>of</strong> <strong>the</strong>
world's oceans and less than 0.3% <strong>of</strong> <strong>the</strong>ir volume, its macrophyte (i.e., hereafter,
pluricellular Plantae, Chromobionta and Cyanobacteria) epsilon species diversity
represents 12% <strong>of</strong> <strong>the</strong> world's described species, with conspicuous differences according
to <strong>the</strong> considered taxa (e.g. 17% for Fucophyceae, Chromobionta) (Ribera et al., 1992;
Boudouresque, 1997).
It does not appear to be <strong>the</strong> case that what we see is an artefact linked to <strong>the</strong> intensity
<strong>of</strong> scientific investigation being greater than for o<strong>the</strong>r regions <strong>of</strong> <strong>the</strong> world (Fig. 6): larger
seas, with greater intensity <strong>of</strong> scientific investigation than in <strong>the</strong> eastern <strong>Mediterranean</strong>
(e.g. <strong>the</strong> Gulf <strong>of</strong> Mexico, <strong>the</strong> south-eastern coast <strong>of</strong> USA and <strong>the</strong> Caribbean Sea) show a
much lower epsilon species diversity (Fig. 6; Boudouresque, 1997).
Fig. 6. Epsilon species diversity <strong>of</strong> macrophytes (i.e. pluricellular Plantae, Chromobionta and Cyanobacteria):
number <strong>of</strong> species versus surface area (x 1000 km2) <strong>of</strong> <strong>the</strong> biogeographic regions. From Boudouresque
(1997).
ACTES DU DEUXIEME SYMPOSIUM MEDITERRANEEN SUR LA VEGETATION MARINE (ATHENES, 12-13 DECEMBRE 2003)
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