The list of cyanobacterial species of the Czech Republic to the end of 2009.

This article summarizes up to date knowledge of occurrence of Cyanobacteria in the Czech Republic; abundance and ecological characteristics are provided for each species. The list does not contain non-verified findings and questionable or unclear taxa, names of the species and synonymy is in agreement with modern nomenclatural system. Based on these criteria, a total of 505 species have been recorded for the area since 1892, whereas occurrence of only 392 species is known recently. This indicates clear trend towards the decrease of the number of the taxa. Most of the extinct and potentially endangered species are likely of the oligotrophic standing waters and wetlands, as these habitats are considerably disappearing from the area of the CR.