Samples from individual canals are visibly split according to the first and second canonical axes, and also according to the distance from the centre of the graph (Fig. 3). Samples from the Patinsk´ y canal (drainage-irrigation canal) are in the centre of the graph. They are the most indifferent to the analysed factors. Drainage canals are more differentiated and the canals with a specific function are most distant from the graph centre. They have a particular species composition and are correlated with several factors to a greater degree.