Effects of non-native turf-forming Rhodophyta on mobile macro-invertebrate assemblages in the north-western Mediterranean Sea

Abstract

The study compared mobile macro-invertebrate assemblages invaded by the two turf-forming invasive macroalgae Womersleyella setacea and Lophocladia lallemandii with non-invaded assemblages. The study was carried out at Pianosa Island, in the Tuscan Archipelago National Park, within the depth ranges where the two invasive species showed high abundance: 35 m depth for Womersleyella setacea and 10 m depth for Lophocladia lallemandii. Results showed significant differences between invaded sites and non-invaded ones for the two turf-forming Rhodophyta. Invaded assemblages showed a lower species richness and a reduction of decapods and molluscs and an increase of polychaetes compared with non-invaded ones. Amphipods showed a drastic reduction in abundance in sites invaded by W. setacea, while they appeared less influenced by the presence of L. lallemandii. Womersleyella setacea showed more severe effects than L. lallemandii, causing deep changes in the structure of assemblages and a reduction of beta diversity of the system.

Key words:

• Algal turfs
• biological invasions
• Lophocladia lallemandii
• Mediterranean Sea
• mobile macro-invertebrates
• Womersleyella setacea

Acknowledgements

We are grateful to Adriana Giangrande and Traudi Krapp for their help for the determination of polychaetes and amphipods. We wish to thank the Coop Ormeggio of Piombino for logistical assistance.

Supplementary material

Supplementary material for this article is available via the Supplemental tab of the article's online page at http://dx.doi.org/10.1080/17451000.2014.952310

Editorial responsibility: David Thieltges

Additional information

Funding

The study has been supported by the Italian National Research Council (CNR) and Regione Toscana (‘Tuscan Check’ Project).