In 1993-1994, larvae and imagines of Odonata were collected in 10 arms of the river Danube. Odonata larvae were also collected during the hydrobiological research of the Morava river basin in 1990-1993.
Following the method of hierarchical classification, based on the presence of dragonfly species at selected localities, we distinguished the characteristic biotopes, as follows: 1) lentic biotopes renewed and newly formed, with undercurrents and rippling inhabited by rheophilous dragonflies, Calopteryx splendens, Platycnemis pennipes and the pioneer species, Anax imperator; 2) drying, unstable, euthrophic biotopes are inhabited by the coenosis Lestes-Sympetrum sp.; 3) original stagnant waters inhabited by the ceonosis Orthetrum-Libellula depressa and Erythromma-Anax imperator; 4) original localities with larger areas inhabited by the coenosis Lestes-Sympetrum-Aeshna sp.; 5) lotic biotopes of the river Rudava with the coenosis Cordulegaster-Ophiogomphus cecilia, comprising the rare species, Ophiogomphus cecilia.