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228 Mannino & Balistreri: An updated overview of invasive Caulerpa taxa ...

Fig. 3. Caulerpa species in different benthic assemblages along the coasts of Sicily and of circum-
Sicilian Islands. A) Caulerpa cylindracea with Posidonia oceanica (Secca del Cammello -
Marettimo, 28 m depth; photo Gianluca Neri); B) Caulerpa cylindracea with macroalgae and
sponges (Secca del Toro – Favignana, 15 m depth; photo Sergio Zanoni); C) Caulerpa taxifolia in a
Posidonia oceanica meadow (Strait of Messina, 12 m depth; photo Alessandro Pagano); D) Caulerpa
taxifolia var. distichophylla in a Cymodocea nodosa meadow (Termini Imerese coast, 9-10 m depth;
photo Marco Toccaceli).

Caulerpa taxifolia var. distichophylla
Distribution (Table 2 and Fig. 5): Caulerpa taxifolia var. distichophylla was first record-
ed on south-eastern coasts of Sicily in 2007 (as C. distichophylla, first Italian record).
From then it spread rapidly along the southern coast and recently it was recorded along the
northern and eastern coast. A new record (Termini Imerese) is here reported. From 2007 to
2009, 85 km of the south-eastern coast of Sicily (Isola delle Correnti, Capo Passero and
Punta Braccetto) were already affected by C. taxifolia var. distichophylla.
Colonisation level: the level of colonisation ranged from sparse individuals to
patches (about 100 cmq) whereas the substratum cover (%) mainly ranged from 8% to
over 50%. In the southern coast its density showed an increasing gradient going from
the west to the east.
Habitat (Fig. 2C, 3D): this alga occurs in shallow waters on sandy and rocky bottoms,
mixed to C. cylindracea, on dead matte as well as along the borders of P. oceanica mead-