A worrying arrival: the first record of brown macroalga Rugulopteryx okamurae in Madeira Island and its invasive risk
Alejandro Bernal‐Ibáñez, Sahar Chebaane, Juan Sempere‐Valverde, João Faria, Patrício Ramalhosa, Manfred Kaufmann, Marta Florido, Andrea Albert-Fonseca, João Canning‐Clode, Ignácio Gestoso, Eva Cacabelos
Abstract
The brown macroalgae Rugulopteryx okamurae is described as one of the most \nsevere and threatening invasive marine macroalgae in European waters. This study \nreports the first record of R. okamurae in the Madeira archipelago, which represents \na new southern distribution limit of this species in NE Atlantic European waters. \nMorphological and molecular characters were used to confirm the species' identity, \nand its potential invasion risk in Madeiran waters was screened using the standard \nrisk assessment tool AS-ISK. Results show that R. okamurae has a medium-high risk \nof becoming invasive in Madeira Island under present and future climate scenarios. \nThe greater risk of impact involves suppressing local species growth and the \nmodification and degradation of local habitats, including trophic cascade effects. \nHowever, environmental and commercial impacts could also occur in case of an \nexplosion of the invasive populations. This new introduction in Madeira coastal \nwaters emphasises the need for regular monitoring of R. okamurae, particularly to \nassess population dynamics to avoid establishing and further expansions. Finally, \nwe recommend the evaluation of the possible derived impacts affecting rocky \ncoastal communities and adopting the necessary mitigation measures and policies.