Dragonflies and damselflies, Odonata, distribution, protected and threatened species, bioindication.

The database of the Czech Union for Nature Conservation (ČSOP) comprises altogether 73 dragonfly species from the CR territory, the recent occurrence of 70 of these species has been confirmed. Odonatological data from the period before 1990 are very scant. Therefore we cannot draw any general conclusions concerning trends in the development of population numbers and of the expansion or recession of single species. In spite of the mentioned circumstances, a prominently negative trend is obvious in the case of some species as for example in Coenagrion lunulatum, Coenagrion ornatum, Sympetrum depressiusculum, and Leucorrhinia caudalis. Opposite trends, e.g. the expansion of thermophilous species such asAeshna affinis, Anax parthenope, Crocothemis erythraea, Orthetrum albistylum and Sympetrum meridionale, seem to appear. However, it would be premature for secured conclusions as only data from the last few years are available.