Proceedings of the Second Mediterranean Symposium on Marine

PROCEEDINGS OF THE SECOND MEDITERRANEAN SYMPOSIUM ON MARINE VEGETATION (ATHENS, 12-13 DECEMBER 2003)
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Under high wave energy, Cystoseira crinitophylla was dominant. This result is in
accordance with previous observations from <strong>the</strong> Aegean (Montesanto and Panayotidis,
2000). The accompanying species are less abundant in Site 1 than in Site 2 probably
because <strong>the</strong> high wave energy <strong>of</strong> Site 1 plays a limiting role on <strong>the</strong> settlement <strong>of</strong>
seasonal or opportunistic species. This lack <strong>of</strong> competition for C. crinitophylla in Site 1
could also account for <strong>the</strong> highest coverage found in this site. The Cystoseira association
in Site 2 is more balanced. The moderate wave energy here is not a limiting factor for
<strong>the</strong> settlement <strong>of</strong> o<strong>the</strong>r species. This could explain <strong>the</strong> highest numbers <strong>of</strong> species and
coverage for Rhodophyta and <strong>the</strong>refore <strong>the</strong> highest values <strong>of</strong> <strong>the</strong> diversity and evenness
indices. The numbers <strong>of</strong> species for Phaeophyceae were <strong>the</strong> highest in Site 2 as well.
The hierarchical clustering that derived from <strong>the</strong> Bray-Curtis similarity matrix gave <strong>the</strong>
dendrogram presented in Figure 1. The replicates <strong>of</strong> each site are grouped toge<strong>the</strong>r with
high similarity values. Sites 1 and 2 (high wave energy) formed one group (similarity
50.76%). In <strong>the</strong> MDS plot (Figure 2), <strong>the</strong> Euclidean distances among <strong>the</strong> sites give us
more information. Sites 1 and 2 are strongly grouped toge<strong>the</strong>r.
The Cystoseira associations in <strong>the</strong>se two sites construct typical aspects <strong>of</strong> <strong>the</strong>
Cystoseiretum crinitae Molinier 1958. This is a common association for moderately
exposed coasts <strong>of</strong> <strong>the</strong> <strong>Mediterranean</strong> with most frequent species C. crinita and
C. compressa (Giacccone and Bruni, 1973). In <strong>the</strong> Aegean Sea, Montesanto and
Panayotidis (2000) have found that C. crinitophylla replaces C. crinita in highly or
extremely exposed areas.
C. foeniculacea f. tenuiramosa was <strong>the</strong> dominant species in <strong>the</strong> moderately sheltered
site (Site 3). This species is obviously tolerant to <strong>the</strong> conditions <strong>of</strong> low wave energy. In
addition, <strong>the</strong> re-suspension <strong>of</strong> <strong>the</strong> fine sand among <strong>the</strong> boulders could create high
turbidity conditions. Ercegovic (1952) suggested that C. foeniculacea f. tenuiramosa
(=C. schiffneri f. tenuiramosa) is favored by conditions <strong>of</strong> low wave energy and
transparency. The poor contribution <strong>of</strong> <strong>the</strong> accompanying species to this Cystoseira
association and <strong>the</strong> very high coverage <strong>of</strong> C. foeniculacea f. tenuiramosa probably
account for <strong>the</strong> lowest values <strong>of</strong> <strong>the</strong> diversity and eveness indices here. C. foeniculacea
f. tenuiramosa was <strong>the</strong> dominant species in <strong>the</strong> most sheltered site (Site 4). The lowest
number <strong>of</strong> species and <strong>the</strong> lowest total coverage were found here as well.
In <strong>the</strong> dendrogram <strong>of</strong> Fig. 1, Sites 3 and 4 (low wave energy) formed ano<strong>the</strong>r distinct
group with lower similarity (38.39%) than Sites 1 and 2. In <strong>the</strong> MDS plot, Sites 3 and 4
formed two distinct groups. The lower similarity here could be attributed to <strong>the</strong> presence
<strong>of</strong> different epiphytic species in <strong>the</strong> two sites.
Cystoseira schiffneri has a problematic taxonomy (Ercegovic, 1952). The associations <strong>of</strong>
C. foeniculacea and C. barbata were first described by Feldmann (1937) in protected
areas where <strong>the</strong> hard substrate was occasionally covered by sediments. Athanassiadis
(1987) also found C. foeniculacea in protected sites <strong>of</strong>ten. Montesanto and Panayotidis
(2000) found that C. foeniculacea (=C. scheffneri) accompanies C. crinita and C.
compressa in sheltered or moderately exposed sites in <strong>the</strong> Aegean.
The Cystoseira associations in <strong>the</strong>se two sites do not correspond clearly to any <strong>of</strong> <strong>the</strong>
associations described so far from <strong>the</strong> <strong>Mediterranean</strong>. Giaccone and Martino (2000)