Environmental factors determining the distribution patterns of invasive Raphidiopsis raciborskii and R. mediterranea in Central East Europe

Mikołaj Kokociński^1*Caio Graco-Roza²Iwona Dorota Jasser³Jurate Karosienė⁴Jurate Kasperovičienė⁴Justyna Kobos⁵Judita Koreivienė⁴Joanna Dorota Mankiewicz-Boczek⁶Janne Soininen²Agnieszka Szczurowska⁷

• ¹Adam Mickiewicz University, Poznań, Poland
• ²University of Helsinki, Helsinki, Uusimaa, Finland
• ³University of Warsaw, Warsaw, Masovian, Poland
• ⁴Nature Research Centre, Vilnius, Lithuania
• ⁵University of Gdansk, Gdansk, Pomeranian Voivodeship, Poland
• ⁶European Regional Centre for Ecohydrology, Polish Academy of Sciences, Łódź, Łódź, Poland
• ⁷University of Life Sciences of Lublin, Lublin, Lublin Voivodeship, Poland

In recent decades, the invasive cyanobacteria Raphidiopsis raciborskii and Raphidiopsis mediterranea have expanded their distribution globally, particularly in temperate regions. Understanding the ecological drivers of Raphidiopsis distribution is imperative to addressing the challenges associated with these species. Here, we aimed to characterize the distribution and biomass of R. raciborskii and R. mediterranea across 112 lakes in Poland and Lithuania in relation to local and regional factors. R. raciborskii occurrence has increased in eastern regions of Poland but biomass is relatively low compared to western Poland, likely due to lower air temperatures and nutrient concentrations, especially phosphorus. In contrast, R. mediterranea only occurred in a small number of lakes in Poland, and in a single lake in Lithuania, with no relation to measured local and regional variables. Our study shows contrasting patterns in the distribution of two invasive cyanobacteria species in Europe, highlighting the importance of climate and nutrients to the distribution of R. raciborskii, the most widespread species, and providing relevant information for decision making and conservation strategies.