Invasive water hyacinth ( Pontederia crassipes ) extends its range to East Europe and the Caucasus

Pontederia crassipes, one of the most invasive aquatic plants in the world, in recent years began to spread in East Europe, as was anticipated by species distribution models. We have documented P. crassipes on the eastern shore of the Black Sea (Pitsunda town), the only area potentially suitable for P. crassipes under the current climate conditions, according to the modeling, where the species has not been registered yet in nature until now. The revealed location is situated in the Colchis, an important refugium and global biodiversity hotspot. As the species has strong negative impact on biodiversity, monitoring of the Pitsunda population and, if it appears to be established, its eradication is crucial. Continuous monitoring of water systems in East Europe, Caucasus and even Siberia is essential to detect further spread and possible establishment of P. crassipes.