Original paper

Back again: The reappearance of Diaphanosoma brachyurum in Lake Constance

Stich, H.B.

Abstract

Diaphanosoma brachyurum disappeared from the cladoceran community of Lake Constance in 1962 but reappeared in 2001. The disappearance coincided with eutrophication and the reappearance with oligotrophication of the lake. This was surprising, as Diaphanosoma brachyurum is often characterized as a species that favours meso- to eutrophic habitats. In 2001, the cladoceran occurred from late summer until autumn reaching maximum density in September that coincided with a high density of small algae. Vertical distribution of Diaphanosoma brachyurum was typically restricted to the upper 10m to 20m of the water column. Besides oligotrophication, the reappearance coincided with a low abundance of whitefish, Leptodora kindtii and Daphnia galeata. Although the ultimate cause is unknown, reduced predation and competition likely contributed to the reappearance of Diaphanosoma brachyurum in Lake Constance.

Keywords

diaphanosoma brachyurumlake constanceoligotrophicationre-establishment