Wittmann, Gundacker, Hönlinger & El Sayed 1997
Wittmann, Gundacker, Hönlinger & El Sayed 1997
WITTMANN, K. J., C. GUNDACKER, M. HÖNLINGER & H. EL SAYED, 1997: Verstädterung von Süßwassermollusken am Beispiel der Großstadt Wien. Abstractband des Symposium "Ökologie und Taxonomie von Süßwassermollusken", Salzburg 1997. 1p.
Urbanization of fresh water molluscs: the fauna of Vienna as a striking example.
The presence of aquatic mollusc species was studied on 630 stations in 231 waters of the city of Vienna in relation to characteristics of biotope, flora and fauna, modes of anthropogenic use, possible indications of anthropogenic impact and data on hydrology. 65 mollusc species were found, eight of which only as shell residuals. By comparison of findings of living species with that of shell residuals and literature data, conclusions could be drawn concerning possible endangerement of species and extinction processes. Abundance and distribution of the original natural mollusc fauna was restricted by numerous factors. In particular, heavy regulation and hydrologic isolation of waters, ground water regression, and degradation of water quality were andare detrimental factors.
Former and ongoing extinction processes were dominated by flood-protection constructions and water pollution. However, todays greatest problems occur in the still species-rich but hydrologically isolated flood plain forests of the Danube River. Euhydrophilous species are endangered by desiccation of their aquatic habitats. The remains of the former oligorheophilous fauna are endangered by the absence of the former riverine dynamics of the flood plain. A number of species retained into smaller areas within their near-natural habitats in the flood plain forests.
However, several original faunal elements of the former flood plains of the Danube disappeared from their near-natural habitats and retained themselves into harbours, floodprotection constructions and similar anthropogenic water bodies. In this way a hemerotolerant urban fauna was formed which now is characterized by regressive distribution types, generalists and neozoans.
Danube; freshwater; ecology; extinction; endangered species
Bivalvia; Gastropoda