Similarities between the interstitial ostracod fauna of the main channel and a backwater of the River Danube in Lower Austria
Danielopol, D. L.; Baltanas, A.
The ostracod fauna inhabiting the alluvial sediments of gravel-bars at three sites on the left side of the main channel of the Danube, at Melk, Vienna and the confluence with the river March, is compared with two sites of an older side-arm, the backwater system Eberschüttwasser. Both epigean and hypogean species live within the alluvial sediments of these two distinct habitats. The ostracod species were hierarchically grouped according to their shared, "derived" similarity, using a numerical cladistic method. The ostracod fauna of the main channel and that of the backwater have in common two exclusively groundwater species. The interstitial assemblages of the Eberschüttwasser differ mainly from those of the Danube channel by sharing two surface-dwelling species which commonly occur in stagnant or slowly-flowing water. The major environmental differences which possibly produced the observed distribution patterns are briefly mentioned.