Multi-method distribution modelling of an invasive crayfish (Pontastacus leptodactylus) at Eurasian scale

Globally, human activities profoundly influence biodiversity, frequently favouring biological invasions. Crayfish, prominent invaders on multiple continents, pose significant varied threats. Using species distribution models (SDMs), this study explores the current and future potential distribution of Pontastacus leptodactylus, a widely introduced but under-studied crayfish, at Eurasian scale. Climate is crucial for most species’ distributions and historically SDMs focused primarily on these variables, while overlooking other environmental factors influencing species occurrence. This research employed 2 approaches: one climatic and one broader environmental model encompassing soil pH and elevation data. Both methods revealed high suitability for the species, particularly currently in Central-Europe. Future climate scenarios for 2050 do not seem to favour the species in terms of intermediate-high suitability regions, with contractions also in the native regions with both approaches. However, remarkable discrepancies were observed in some North-European regions; with the climatic approach predicting high suitability where the environmental approach did not. This study identifies P. leptodactylus as a widespread successful species outside its native range with potential for expansion under current conditions. The synthesised continental overview and projected distribution maps aid in prioritising monitoring and prevention efforts while underlining the importance for using environmental as well as climatic variables in SDMs.