New records of the rare glacial relict Eurytemora lacustris (Poppe 1887) (Copepoda; Calanoida) in atypical lake habitats of northern Germany

Abstract

During monitoring investigations of lakes in Schleswig-Holstein (northern Germany) in 2000 and 2008, the calanoid copepod Eurytemora lacustris (POPPE 1887) was found in three lakes of the Ratzeburger Lake complex: the Kleine Küchensee, the Große Küchensee and the Große Ratzeburger See. The species has a broad geographic distribution but has become rare and endangered by eutrophication and global change. The lakes are mesotrophic (Gr. Ratzeburger See) and eutrophic (Kl. Küchensee, Gr. Küchensee) with cool (1 mg O2 L-1). Food and physical conditions seem to be favourable enough to permit survival and reproduction of the species at least in spring. It remains unclear, however, whether the populations in the studied lakes are autochthonous. Eurytemora lacustris possibly invaded the lakes or was transported via a canal from the Schaalsee upstream, where a viable population exists.

Keywords

• calanoid copepod, endangered species, glacial relict, atypical habitat