Climate change and alien species invasions are leading to significant diversity loss and affect ecosystem functioning worldwide. In the NW Mediterranean the occurrence of unprecedented mass mortality events in macroinvertebrates species have been related to strong positive temperature anomalies possibly linked to climate change. On the other hand, in the Mediterranean there is an increasing number of invasive species. Up to now, most studies focus only on the effects of single disturbance source, although the potential combined effects of different disturbances are raising concern. This project will examine the direct and potential combined effects of climate change and the invasion of an algal species in the Mediterranean coralligenous, the richest one in terms of both species and organization among the Mediterranean benthic communities. It harbours great number of endangered species and long-lived organisms, which are very sensitive to strong disturbances. Among them gorgonians are key-species in coralligenous communities which were severely affected by recent mass mortality events. Conversely, the actual spreading of an invasive algae species, Womersleyella setacea, may be causing strong impacts in the community and could be a major threat for the recovery process for gorgonians species. This project will firstly focus in obtaining baseline data community level to assess the impact of disturbances (present and future). Secondly, factors that favour spreading of the invasive species Womersleyella setacea will be assessed. Thirdly, factors controlling recovery processes and sensibility of gorgonian species to both disturbance sources and potential combined effects will be elucidated. The expected results will provide the proper scientific context for the management of the rich Mediterranean coralligenous biodiversity facing two of the most serious global threats: climate change and alien species invasions.