engleski

Distribution of Graphoderus bilineatus (De Geer, 1774) in Croatia – first results

The dytiscid water beetle Graphoderus bilineatus (De Geer, 1774) is one of few beetles protected by the European Habitats Directive (Annex II and IV of Council Directive 92/43/EEC) as well as by Bern Convention (Annex II), and is listed in the IUCN Red List of Threatened Species. It is a west Palaearctic species, however, in most European countries the species is very rare and West and Central European populations are strongly declining. So far, only two old records are known in Croatia (1907 Paukovec and 1943 Migalovci). During 2010 we conducted a survey at these two old known and three new potential localities for the species occurrence in order to designate Natura 2000 sites for the species. In total, 35 sampling sites were selected. In addition to sampling by pond-net, two bottle traps with bait were placed at each site. We discovered two new populations of G. bilineatus and collected information on distribution and habitat of this species in Croatia. Populations of G. bilineatus were recorded at 14 sampling sites along the natural wetlands of Lonjsko Polje and Kopački Rit Nature Parks (N = 53). On the other hand, in the flooded forest of Spačva basin, or at the old known localities we have not found any specimens of G. bilineatus. Majority of specimens occurred in flood-meadows and in canals or oxbows with stagnant waters with riparian and aquatic vegetation of medium density.

Graphoderus bilineatus

nije evidentirano