Extinction processes and secondary biotopes in urban areas: the endangered oligorheophilic molluscan fauna of the River Danube
Wittmann, K. J.; Gundacker, C.; Hönlinger, M.; El Sayed, H.
Part of the molluscan fauna that inhabited coves, side-arms and tributaries prior to regulation of the River Danube, survived in stagnant waters of riverine forests in Vienna. Here the fauna gradually became reduced due to dessication (terrestrification) and/or unfavourable hydrological and sedimentological conditions that were late consequences of the separation from the river. At least 14 species retreated into smaller areas within the riverine forests. At least another 14 species were gradually displaced from backwaters and have found (transient) shelter in urban harbours and anti-inundation constructions, leading to the establishment of a hemerotolerant urban fauna.