REDISCOVERY OF LEPTESTHERIA-DAHALACENSIS AND EOLEPTESTHERIA-TICINENSIS (CRUSTACEA, BRANCHIOPODA, SPINICAUDATA) - AN OVERVIEW ON PRESENCE AND CONSERVATION OF CLAM SHRIMPS IN AUSTRIA

According to recent literature, five of the six known Austrian 'concho stracan' species are extinct. However, interim results of a current st udy on large freshwater branchiopods in Austria show that five species still occur at a restricted number of sites in the Pannonian region o f Lower Austria. The clam shrimps Leptestheria dahalacensis and Eolept estheria ticinensis were rediscovered in May 1994 in the flood plains of the river Morava near Marchegg. Imnadia yeyetta and Cyzicus tetrace rus have been known to the authors in the same region since 1981, and 1992, respectively. Limnadia lenticularis occurs in the flood plains o f the rivers Morava and Danube. Lynceus brachyurus, the only Austrian representative of the Laevicaudata, was not found and most probably go t extinct. All Austrian clam shrimp species are considered to be endan gered. Main threats are agricultural activities and artificial changes of the hydrologic conditions. Conservational measures are discussed f or their effectivity.