Page 3 - MANNINO_BALISTRERI

50° Congresso della Società Italiana di Biologia Marina
Livorno, 10-14 giugno 2019
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Two sites distant more than 500 m were considered different. The records refer to three
different habitats: vermetid reef, Cystoseira communities (upper infralittoral zone) and
coralligenous formations (Fig. 1). The alga was mainly present in the Cystoseira
communities and in the vermetid reef, and grew well in both substrates (see Tab. 1). In
the Cystoseira communities and in the coralligenous formations the class of coverage
(%) was mainly 2 (20-50%), whereas in the vermetid reef was mainly 3 (>50%).
Useful information on the colonisation strategies of the alga was also gathered, e.g. the
ability of the stolons to create bridges in order to reach new areas for the anchorage
(Fig. 1b). It has also been observed that the increase of sedimentation among the
stolons of C. cylindracea favoured the settlement of the biofouler worm Branchiomma
bairdi (McIntosh, 1885) (see Mytilineou et al., 2016) (Fig. 1a).

Fig. 1: C. cylindracea and Branchiomma bairdi (a), a bridge created by the stolons of C. cylindracea
(b), C. cylindracea in a coralligenous formation (c) and C. cylindracea in a vermetid reef (d).
C. cylindracea e Branchiomma bairdi (a), un ponte creato dagli stoloni di C. cylindracea (b),
C. cylindracea in una formazione coralligena (c) e C. cylindracea in un reef a vermeti (d).

Conclusions - Favignana is the island of the Aegadian archipelago most affected by
the introduction of alien species (Mannino et al., 2016, 2017; Mannino and Balistreri,
2018). In comparison with the other two main islands (Marettimo and Levanzo), it
presents the highest number of C. cylindracea records along with the highest number
of NIS. This is consistent with the central position of Favignana, from both a
geographical and a transport-stowaway point of view; it is the island nearest to the
Trapani coast as well as the one with the most intense naval traffic and the highest
number of tourists. In comparison with the other Sicilian MPAs, the Egadi Islands
MPA has the highest number of NIS and, among the three islands of the Aegadian
archipelago, Favignana Island is the most affected by the introduction of NIS
(Gianguzza et al., 2018). Our findings would suggest that protection does not hinder
the introduction and spreading of NIS, which instead represent a real threat to native
species and habitats deserving protection at Community level (Habitats Directive
92/43/EEC) such as coralligenous formations and vermetid reefs.

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