Preprint volume - SIBM

Pre-print Volume - Oral presentations
Topic 1: BIODIVERSITY AND CONSERVATION SCIENCE: CONTRIBUTING TO MANAGEMENT
an area of 400 cm 2 (Bianchi et al., 2003). For each of the 16 samples (more 16
replicates), the main macroalgal taxa were identified; Molluscs (Poliplacophora,
Gasteropoda and Bivalvia), Polychaetes and Decapods were identified at specific level
(Bianchi et al., 2003). The quantitative and qualitative results as well as the
environmental factors, like seasonal hydrodynamism, wind exposition and substratum,
were analyzed through Cluster Analysis, n-MDS Analysis, and Symper Analysis using
Primer v6 β. The biodiversity level was assessed by means of Shannon-Weaver Index.
As regard Posidonia oceanica beds, shoots density in upper, middle, and lower zones,
maximum depth and type of the lower limit were analyzed (Buia et al., 2003). In
addition, a Pinna nobilis population, present in upper zone of the southern meadow,
was studied in detail; for each specimen, settlement depth was noted down, maximum
width and length of the bigger valve were measured.
Results – The northern coast is in front of the open sea and exposed to winter winds
action (high hydrodynamism area); the southern coast is located inside the Viticcio
Gulf and sheltered from these winds (low hydrodynamism area). Photophilic algae
community is typical of mesolittoral and upper infralittoral hard substrata: Cystoseira
spp., Padina pavonica, Stypocaulum scoparium, Rissoella verrucolosa, Acetabularia
spp. are the main observed taxa. In N area 2591 specimens, belonging to 98 species (37
Molluscs, 49 Polychaetes, and 12 Decapods), were identified compared to the 2201
ones, belonging to 157 species (63 Molluscs, 73 Polychaetes and 21 Decapods), in S
area. Thirty-eight species characterized N area, 93 species the S one; 64 species are
common to both areas. In the southern part of the istmus, species typical of high
hydrodynamic conditions, such as the Polychaetes Syllis armillaris and Perinereis
cultrifera (Bellan, 1969), were found.
In the two sites, Polychaetes are the richest taxon as regard the number both of species
and specimens; a conspicuous quali-quantitative increase of this taxon is evident in
September, more pronounced in respect to the other taxa.
The total biodiversity level is high in all the stations: Shannon-Weaver Index shows
noticeable values, especially as regard the samples relevant to the S area (Fig. 2).
Fig. 2 - Shannon-Weaver Index. N area samples (sample and replicate), in black, S area samples (in
grey).
Indice di Shannon-Weaver per i campionamenti (campione e replica) nell’area N (in nero) e
nell’area S (in grigio).
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
63
Legend
RE = rocky bottom, E side, N area
SE = rocky bottom, E side, S area
RW = rocky bottom, W side, N
area
SW = rocky bottom, W side, S
area
BN = quay, N side, N area
ME = mole, E side, S area
BW = quay, W side, N area
MW = mole, W side, S area
-M = samples of May
-S = samples of September