SCIENTIA MARINA 84(2) June 2020, 181-191, Barcelona (Spain) ISSN-L: 0214-8358 https://doi.org/10.3989/scimar.04984.06A The ecological condition of vermetid platforms affects the cover of the alien seaweed Caulerpa cylindracea Marc Terradas-Fernández 1, Miguel Valverde-Urrea 1, Nuria Casado-Coy 1, Carlos Sanz-Lazaro 2,3 1 Departamento de Ciencias del Mar y Biología Aplicada, Facultad de Ciencias, Universidad de Alicante, Aptdo. Correos 99, 03080 Alicante, Spain. (MT-F) (Corresponding author) E-mail:
[email protected]. ORCID iD: https://orcid.org/0000-0002-1916-5337 (MV-U) E-mail:
[email protected]. ORCID iD: https://orcid.org/0000-0002-5708-5258 (NC-C) E-mail:
[email protected]. ORCID iD: https://orcid.org/0000-0003-4348-2225 2 Departamento de Ecología, Universidad de Alicante, P.O. Box 99, E-03080 Alicante, Spain. 3 Multidisciplinary Institute for Environmental Studies (MIES), Universidad de Alicante, P.O. Box 99, E-03080 Alicante, Spain. (CS-L) E-mail:
[email protected]. ORCID iD: https://orcid.org/0000-0002-4431-1762 Summary: The seaweed Caulerpa cylindracea Sonder is one of the most important invaders on Mediterranean rocky shores. However, many driving pressures affecting its spread are poorly understood and seem to involve the interactions between abiotic and biotic factors. We studied the invasiveness of C. cylindracea on two shallow vermetid platforms with a con- trasting ecological status on which C. cylindracea was first detected simultaneously 15 years ago. The cover values of C. cylindracea and the other macroalgal species were assessed for one year, embracing the whole platform width.