Mapping the global distribution and predicting the potential expansion of Ceratium (Dinophyceae): development of an interactive platform

Abstract

Ceratium is a genus of freshwater dinoflagellates distributed worldwide and considered invasive in several aquatic systems around the world. This study introduces a global database documenting Ceratium species that includes 677 records published from 1881 to 2023, and 42 new ones. These encompass a large part of the vast bibliography surrounding the genus described in 1793, or under its basionym Bursaria in 1773. To visualize these records along with the associated environmental information, we developed an interactive and updatable web platform named "Ceratium Tracker" (https://hjqcwk-mica-milano.shinyapps.io/CeratiumTracker/). As South America had the highest number of recent records, we calculated the expansion rate and modeled the potential distribution in this region, focusing on the most frequent species: C. furcoides and C. hirundinella. We found that C. hirundinella had a lesser expansion magnitude compared to C. furcoides, but its invasion in South America started earlier. Within just a decade, from 2002 to 2012, C. furcoides rapidly expanded its range, invading approximately 70% of South America. Our analysis showed that minimum temperature and soil moisture were the variables most influencing the potential distribution of C. furcoides in South America, while actual evapotranspiration was key for C. hirundinella. Consequently, areas most susceptible to C. furcoides were primarily located along Brazil’s coastal region and neighboring countries. In contrast, susceptibility areas for C. hirundinella were concentrated in western Argentina and Chile, consistent with the environmental preferences obtained from our analyses.