How the invasive algae Rugulopteryx okamurae affect coastal biodiversity? Insights from coastal fish communities of gran Canaria (NE Atlantic Ocean)

Biological invasions present significant threats to global biodiversity and ecosystem functioning. The introduction of invasive species can lead to ecosystem homogenization, altering community dynamics and negatively impacting native species and habitats. Rugulopteryx okamurae, a brown seaweed native to the Northwest Pacific, has rapidly invaded marine ecosystems in Europe, transforming coastal habitats. This study examines the impact of R. okamurae on fish communities across different zones of Gran Canaria, with a particular focus on the invasion gradient. We observed significant variations in fish species abundance and richness across sites, with a noticeable trend towards reduced diversity and a higher prevalence of opportunistic species in areas heavily invaded by R. okamurae . The invasion gradient, rather than typical edge effects, appeared to play a more substantial role in shaping community structure, suggesting that the pervasive spread of R. okamurae leads to habitat homogenization. Ongoing monitoring and adaptive management strategies are crucial to fully understand and mitigate the impacts of R. okamurae on marine biodiversity in Gran Canaria. • Investigated the impact of Rugulopteryx okamurae invasion on fish communities in Gran Canaria. • Found significant reductions in fish diversity and increased dominance of opportunistic species in heavily invaded areas. • Observed less pronounced edge effects in regions with high R. okamurae coverage. • Urgent need for ongoing monitoring and adaptive management strategies to mitigate the impacts of R. okamurae . • Provided insights into the mechanisms by which invasive species alter native ecosystems and community dynamics.