Proceedings of the Second Mediterranean Symposium on Marine
Proceedings of the Second Mediterranean Symposium on Marine
Proceedings of the Second Mediterranean Symposium on Marine
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PROCEEDINGS OF THE SECOND MEDITERRANEAN SYMPOSIUM ON MARINE VEGETATION (ATHENS, 12-13 DECEMBER 2003)<br />
194<br />
Six samplings were carried out between<br />
summer 1998 and spring 2002 (August 98,<br />
March 99, June 99, June 01, September 01 and<br />
March 02) in order to m<strong>on</strong>itor <str<strong>on</strong>g>the</str<strong>on</strong>g> marine<br />
benthic vegetati<strong>on</strong> characteristics. The sampling<br />
was destructive (1 random sample from a<br />
permanent stati<strong>on</strong>-square 5 x 5 m per sampling<br />
period) <strong>on</strong> a quadrate 20cm x 20cm, which is<br />
c<strong>on</strong>sidered to be <str<strong>on</strong>g>the</str<strong>on</strong>g> minimal sampling area in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>Mediterranean</str<strong>on</strong>g> infralittoral<br />
communities.<br />
Phytobenthos community structure was<br />
analyzed in terms <str<strong>on</strong>g>of</str<strong>on</strong>g> species number, total<br />
coverage, Shann<strong>on</strong>-Weaver diversity (H’, log2<br />
basis) and Pielou evenness (J’) indices.<br />
Fig. 1: The study area<br />
The Ecological Evaluati<strong>on</strong> Index (EEI) was calculated according to Orfanidis et al. (2001),<br />
described also <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> site: www.fishri.gr (Laboratories / <strong>Marine</strong> Ecology / Water quality).<br />
The EEI is an original metric for <str<strong>on</strong>g>the</str<strong>on</strong>g> ecological status evaluati<strong>on</strong> based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>cept <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
morphological and functi<strong>on</strong>al groups (Littler and Littler 1980; 1984). The species were<br />
divided in two Ecological State Groups (ESG):<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> ESG I were grouped <str<strong>on</strong>g>the</str<strong>on</strong>g> thick lea<str<strong>on</strong>g>the</str<strong>on</strong>g>ry, <str<strong>on</strong>g>the</str<strong>on</strong>g> articulate upright calcareous and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
crustose calcareous species. Most <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>m are k-selected species. In <str<strong>on</strong>g>the</str<strong>on</strong>g> ESG II were<br />
grouped <str<strong>on</strong>g>the</str<strong>on</strong>g> foliose, <str<strong>on</strong>g>the</str<strong>on</strong>g> filamentous and <str<strong>on</strong>g>the</str<strong>on</strong>g> coarsely branched upright species. Most <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>m are r-selected species.<br />
Each sampling stati<strong>on</strong> was classified in <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> five classes <str<strong>on</strong>g>of</str<strong>on</strong>g> ES after a simple crosscomparis<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> coverage value <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ESG I and <str<strong>on</strong>g>the</str<strong>on</strong>g> ESG II <strong>on</strong> a matrix (Fig. 2). The<br />
numerical scoring system was used to<br />
express <str<strong>on</strong>g>the</str<strong>on</strong>g> category <str<strong>on</strong>g>of</str<strong>on</strong>g> ecological status as<br />
a number (Bad=2, Low=4, Moderate=6,<br />
Good=8 and High=10).<br />
RESULTS<br />
In total 60 taxa were identified (12<br />
Chlorophyceae, 16 Phaeophyceae and 32<br />
Rhodophyceae). At all <str<strong>on</strong>g>the</str<strong>on</strong>g> studied stati<strong>on</strong>s<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Rhodophyceae were qualitatively<br />
Fig. 2: Matrix for <str<strong>on</strong>g>the</str<strong>on</strong>g> evaluati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ESC<br />
dominant and <str<strong>on</strong>g>the</str<strong>on</strong>g> Phaeophyceae were<br />
quantitatively dominant (Table 1).<br />
The canopy layer <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> vegetati<strong>on</strong> was well developed at Stati<strong>on</strong>s 1, 4, 5 and 6, mainly<br />
due to <str<strong>on</strong>g>the</str<strong>on</strong>g> presence <str<strong>on</strong>g>of</str<strong>on</strong>g> Cystoseira species. O<str<strong>on</strong>g>the</str<strong>on</strong>g>r species, e.g. Dictyopteris<br />
membranacea, formed a pseudo-canopy layer when <str<strong>on</strong>g>the</str<strong>on</strong>g>y were massively present. A<br />
well-developed bushy layer, composed mainly by Jania rubens, Laurencia optusa,