Invasive freshwater algae and cyanobacteria are overlooked: insights from a bibliometric study

Biological invasions represent a critical global challenge, profoundly impacting ecosystems and driving environmental change. While the distribution of invasive animal or plant species has received considerable attention, our understanding of the global prevalence of invasive algae and cyanobacteria in continental freshwater ecosystems remains limited. With the aim of studying how much freshwater algae and cyanobacteria are being detected as invaders, we conducted a comprehensive bibliometric analysis. It revealed 72 reported species as invasive, with R. raciborskii, D. geminata, and C. furcoides emerging as principal ones. Only 52% of the reports quantified or analyzed environmental impacts. Among the documented impacts and environmental alterations, changes in phytoplankton structure and diversity were the most frequently reported, followed by toxin production, particularly associated with invasive cyanobacteria species. Geographically, there is a noticeable concentration of reports, with Africa and Asia being underrepresented. Meanwhile, the Czech Republic and Poland emerge as leaders in the number of species classified as invaders. This geographical bias suggests a significant gap in our understanding of the true distribution of invasive freshwater algae and cyanobacteria species.