Monitoring dragonflies on the section of the Dráva between Ortilos and Vízvár (Insecta: Odonata)

Abstract

The power plant planned on the Croatian section of the Dráva can result in unfavourable changes in the fauna of wetlands by the river and may - among others - affect the dragonflies developing there, too. This necessitates the long-term monitoring of the local dragonfly fauna. Already the experiences of the first few years of monitoring referred to the fact that the shallower wetlands of the area are particularly vulnerable. In the course of the examinations it turned out that the dragonfly fauna of the area is rich -14 of the 48 species detected so far are protected by law. Outstanding among these are the 5 taxons listed in the Bern Convention (Aeshna viridis, Gomphus flavipes, Ophiogomphus cecilia, Leucorrhinia caudalis, Leucorrhinia pectoralis). The composition of the local fauna - similarly to the national situation - is dominated by Pontic-Mediterranean, Siberian and West-Siberian faunal elements. However, the proportions alter to some extent from group to group. The author gives a detailed analysis of the composition of the fauna of the individual sampling sites and offers a separate depiction of the quantitative composition of the fauna according to the subordo.