Page 4 - Macrofaunal_biodiversity_2006

Sampling
Macrofauna sampling was carried out at three parallel transects, spaced one meter
apart from one another. At each transect, Stations 1 and 3 were always situated at 1m
distance above and below the water line, respectively; Station 2 was always on the
waterline and Stations 4 were located at the sublittoral zone at 1m deep. At each sta-
tion two samples were collected by means of cylindrical acrylic corers of 9.4cm inner
diameter, penetrating 25cm deep into the substrate. The samples were sieved through
a 0.5mm mesh and subsequently the animals were fixed in a 5% formalin solution,
buffered with seawater.
For the abiotic factors a sediment sample for the measurement of the redox po-
tential (Eh) and the basic environmental variables was collected at each station by
inserting an additional 4.5cm diameter acrylic corer to a depth of 25cm. Concentra-
tions of particulate organic carbon (POC), chlorophyll-α values in the sediments were
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obtained according to standard procedures outlined in Strickland & Parsons (1972),
Grasshoff et al. (1983) and Parsons et al. (1984). Sediment particle size analysis used
wet sieving through a 63µm mesh to separate coarse and fine fractions, according to
the method proposed by Buchanan (1984).
Salinity and temperature were measured at each station with a refractometer and
an Hg thermometer, respectively.

Analysis
A biotic matrix was initially constructed, including information on the species
composition (presence/absence) in all studied sandy beaches, based on the data collect-
ed both from the sampling activities and from the literature. An additional aggregation
matrix, which included information on the phylogenetic/taxonomic classification of
the species, was constructed.
To derive the similarity pattern from the species composition matrix, the Sørensen’s
coefficient was utilized. The multivariate pattern was obtained from the similarity ma-
trix by using the hierarchical agglomerative classification (Cluster), employing group-
average linking (Clarke & Green, 1988; Warwick & Clarke, 1991).
Both average taxonomic distinctness (AvTD, denoted as Delta values) and var-
iation in taxonomic distinctness (VarTD, denoted as Lambda values) were used to
assess macrofaunal biodiversity of the Mediterranean sandy beaches. Both AvTD
and VarTD statistics were calculated from the species lists of the Meditteranean
sandy beaches considered and departures from expectation were determined by
the corres-ponding simulation funnels, constructed from random subsets of spe-
cies from the regional species pool (Warwick & Clarke 1998, 2001; Clarke &
Warwick, 2001).
The PRIMER software, developed in Plymouth Marine Laboratory, was used.

MEDCORE N. Papageorgiou et alii