Terrestrial Alien Flora of the Iberian Alboran Coast: Assessment, Attributes, and Future Implications

Abstract

Although Mediterranean coastal regions in southern Spain have high floristic diversity and numerous Habitats of Community Interest (HCIs) identified by the European Union Directive Council, they are also vulnerable to invasive plants. In our study, we aimed to create a checklist of terrestrial alien taxa in the Iberian area of the Alboran coast, assess each species’ current invasion, analyse the influence of environmental attributes on invasion, estimate the richness of alien species per HCI group, and evaluate each species’ potential invasiveness based on its reproductive and dispersal attributes. The checklist that we developed includes 123 alien taxa, most belonging to the Asteraceae, Asparagaceae, and Poaceae families. Notably, 20% of the species are super invaders that occupy more than 20% of HCIs. We also identified Aloe vera, Cylindropuntia spp., Agave salmiana, Opuntia spp., and Paspalum spp. as incipient invaders with the potential for future expansion. Although most alien flora in the HCIs are not regulated by Spanish legislation (RDL 630/2013), monitoring and eradication plans are crucial. Advocating the cessation of using those plants in gardens and reducing anthropogenic pressure are also essential, as human activities worsen invasion dynamics and facilitate the introduction and establishment of invasive species.