Page 2 - Giangrasso_alii_2047

644 MARIA GIULIA GIANGRASSO ET ALII

RESULTS AND CONCLUSIONS

A total of 14 taxa were identified, belonging to
crustacean decapods (1), echinoderms (1), molluscs
(8), polychaetes (2) and amphipods (2), the last one
presenting the highest number of individuals. At
Faraglione and Arre Turino the highest number of
amphipods was found (Table 1).
Biodiversity was higher at Cala Rotonda and
Arre Turino, whereas abundances were higher at
Faraglione and Arre Turino (Table 1). Differences
in abundances seem to be linked to the coverage,
Figure 1. The analysed vermetid reefs. A. Scheme of the pat- shape and structural complexity of algae (Cacabelos
tern 1. B. Faraglione. C. Scheme of the pattern 3. D. Arre
Turino et al., 2010). Indeed, Faraglione and Arre Turino
were characterized by 100% algal coverage and by
the dominance of algae with a high structural com-
land (Egadi Islands MPA), located approximately plexity (Laurencia and Cystoseira, respectively). At
five kilometers from the western coast of Sicily Cala Rotonda, the dominance of a sheet-like alga
(South Tyrrhenian Sea, Italy). In this paper we con- (Dictyopteris) would explain the lower number of
sidered 4 representative areas, 2 characterized individuals. At Pozzo, characterized by 30% algal
by a vermetid reef belonging to the pattern1 coverage (Laurencia was the dominant species), the
(Faraglione and Pozzo) and 2 by a vermetid reef lowest diversity was found.
belonging to the pattern 3 (Arre Turinu and Cala The amphipod diversity was very low in all
Rotonda) (Fig. 1) (see Balistreri et al., 2015), sites, only two herbivorous species were found:
where the outer margin was characterized Elasmopus pocillimanus (Spence Bate, 1862), a
respectively by mediolittoral (Laurencia) and in- free-living species, and Ampithoe ramondiAudouin,
fralittoral (Cystoseira, Dictyopteris) algal species. 1826, a tubicolous species. Ampithoe ramondi was
For each site, three random replicates were taken the only species found at Arre Turino and the most
by scraping off the substratum within a 20×20 cm abundant species at Faraglione. This species prefers
frame from the outer margin of the reef. The sam- areas with high hydrodynamism such as the verme-
ples were washed through 0.5 mm sieves and the tid reef and preferentially consumes algae with a
algae were then searched thoroughly for any re- higher structural complexity (Jacobucci & Leite,
maining animals under a stereomicroscope. After 2014).
a sorting process the isolated animals were counted. The present findings suggest that the total abun-
All animals and algae were identified to the lowest dance and species richness of epifauna are mainly
taxonomic level feasible. related to the structure and composition of algal

Algal
Area Dominant alga amphipods decapods echinoderms molluscs polychaetes
coverage
Cystoseira
Arre Turino 100% 27 2 4 10
(100%)
Dictyopteris
Cala Rotonda 100% 13 9 4 2
(90%)
Faraglione 100% Laurencia 30 1 10
(90%)
Laurencia
Pozzo 30% 2 8
(25%)

Table 1. Data of macroalgae and the total number of individuals of epifaunal taxa recorded in the studied vermetid reefs.