Page 3 - DeidunSchembri2006

Mo 1ile fauna of infra lilfora/ fringe of Ma/lese beaches 357

1986), and beach occupancy by humans as an index of the intensity of anthropo-
genic use. These results are summarized in Tab. l.

The fauna collected were sorted, identified and counted. The species were clas-
sified into six feedings types: macrophytophagous, microphytophagous, macrocar-
nivorous, microcarnivorous, omnivorous/scavenger and detritivore feeding modes.
No observations on feeding were made but species were assigned to each category
on the basis of literature reports (mysids - Viherluoto, 2001; polychaetes - Fau-
chald, 1977; Hamond, 1969; decapod crustaceans - Falciai & Minervini, 1992;
cumaceans and tanaids - Blazewicz-Paszkowycz & Ligowsk, 2002; amphipods

- Ruffo, 1998; copepods - Stella, 1984; isopods - Gutow, 2003).
Log-transformed numerica} abundances were used to construct similarity matri-

ces using the Bray-Curtis measure, which were then analysed using non-metric
multidimensional scaling (NMDS) ordination and hierarchical clustering with the

PRIMER 5 statistica! package (Clarke & Warwick, 1994). The BIOENV proce-
dure and regression analysis were used to examine the relationship between com-
munity structure and environmental variables (Clarke & Warwick, 1994), whilst

the SIMPER technique was used to identify which species contributed most to
the differences observed between beaches.

Results

A total of 1699 individuals belonging to 50 different macrofaunal species were
collected from the eight beaches sampled during the two years of study: 9 poly-
chaetes, 2 molluscs, l copepod, l cumacean, 6 mysids, 5 isopods, l tanaid, l O
amphipods, 9 decapod crustaceans, and 6 fish. Nineteen species (55.9% of all
species collected) and 17 species (53.1% of all species collected) were only found
on single beaches during a particular season in the first and second year of sam-
pling, respectively. In addition, 30 species out of the total 50 collected were only
found on a single beach during the entire two year sampling program; the major-
ity of these were decapods and polychaetes (8 species each), followed by fish
and amphipods (5 species each), mysids (2 species) and tanaids and isopods (l
species each). Only two species were collected solely from non-Maltese beaches:
the decapods Philocheras sp. (Pozzallo) and Palaemon elegans (Conigli) - on the
non-Maltese beaches, species richness ranged from 3 (Conigli, Lido Burrone) to 5
(Pozzallo), whilst individuai abundances ranged from 0.20 inds/stroke (Lido Bur-
rone) to 5.53 (Pozzallo). In comparison, species richness and individuai abun-
dances ranged from O (Ramla, Xatt L-Ahmar, spring 2002) to 7 (Golden Bay,
spring 2002) and from O (Ramla, Xatt L-Ahmar, spring 2002) to 5.51 inds/stroke
(White Tower Bay, winter 2003).

For the Maltese beaches, there was very little inter-annual variation in the
total faunal abundances (615 and 728 individuals for the first and second years,
respectively) and in total species richness (33 and 32 species, respectively). There
was also minimal inter-annual variation in relative abundance; mysids and amphi-
pods were the most abundant taxa in both years (33.9% and 32.8% respectively
in 2002, and 37.9% and 33.9% respectively in 2003). In terms of species rich-
ness, amphipods, along with polychaetes, were the most abundant during 2002
(each constituting 17.6% of ali species collected), whilst amphipods, followed by
mysids, were the most abundant during 2003 (constituting 21.9% and 18.8% of all
species collected, respectively). There was more inter-annual variation in species