The Berounka River flows from Plzeň to Prague in W and C Bohemia and has a total length of 138.7 km. Occurrence of the invasive annual species Echinocystis lobata was repeatedly investigated along the entire river. Number of its localities (half-kilometre long sections) and length of its stands were recorded. In 1982, the species was not yet registered at all. In 1992, a single locality appeared near Plzeň and E. lobata has been spreading since then. In 2002, it occurred at 189 of a total of 278 investigated sections of the river. An extreme summer flood mid August 2002 caused a moderate decrease in number of localities to 155, which was followed by an increase again. Three years after the flood (in 2005) the number of localities was 195. A less extreme flood in early June 2013 destroyed young plants and caused reduction of the number of localities to 97.
Echinocystis lobata on Berounka riverbanks
Klára Kabátová, Jan Rydlo, Jaroslav Rydlo