L. Forró szerk.: Miscellanea Zoologica Hungarica 13. 2000 (Budapest, 2000)

Spolwind, R., Schludermann, C. , Schuster, A.; Waidbacher, H.: Comparison of fish and amphibian communities in a floodplain system of the rivers Traisen and Danube westwards of Vienna

MISCELLANEA ZOOLOGICA HUNGARICA Tomus 13. 2000 p. 91-104 Comparison of fish and amphibian communities in a floodplain system of the rivers Traisen and Danube westwards of Vienna by R. Spolwind, C. Schludermann, A. Schuster & H. Waidbacher (Received February 18, 2000) Abstract: Within the framework of a river restauration concept at the river Traisen a simultaneous investigation of fish and amphibian coenoses was performed. Due to human impacts the ecological integrity of many backwater systems is low, evaluating both vertebrate groups is a possible way of a deficit analysis in lentic ecosystems. The results are compared to recent publications, the importance of habitat variability for species richness and co-existence of both groups is stressed and proved. Keywords: Amphibia, Pisces, floodplain, Danube, Traisen, backwaters, inundation area, Austria, river restauration Introduction Between 1996 and 1998 backwaters of the River Traisen and the River Danube were investigated within the river restauration concept GBK (Gewässerbetreuungskonzept) Traisen (Eberstaller et al. 1999). The GBK Traisen, influencing the section from the city of Wilhelmsburg to the mouth into the Danube, was a water resources management concept to protect human settlements from floods and to improve the ecological integrity of the observed systems. The entire region was investigated for the first time at a high and complex ecological level. This paper should further to our existing faunistical knowledge, as well as contribute to a better understanding of possible co-existence between fish and amphibians. GBK concepts show interdisciplinarity on a high level, we had the possibility to investigate fish- and amphibian communities simultaneously and from a similar view. Most publications, dealing with the co-existence of these two vertebrate groups, stress results of selected taxa, whereas the framework of a GBK permits simultaneous and equally weighted field investigations of fish and amphibians. In most publications studying both vertebrate groups (Müller 1968, Flindt & Hemmer 1969, Broggi 1975, Filoda 1981, Clausnitzer 1983a, b, Gebhardt 1985, Hehmann & Zucchi 1985, Dolmen 1987, Bradford 1989, Amtkjaer 1988, Holmen & Wederkinch 1988, Breuer 1992, Banks et al. 1993, Sound & Veith 1994), especially fish data refer mostly to only few selected taxa. Pintar & Spolwind (1998) tried to compile a synopsis of fish and amphibian data in a floodplain area of the Danube near Vienna, where several backwater types could be distinguished, and they stressed the importance of vertical structures and the availability of inundation areas during spawning periods of amphibians for a possible co-existence of both groups. Because of their specific demands to different habitat types during their life cycle amphibians have an important indicator function in evaluating aquatic systems and their semiterrestrial and terrestrial surroundings (Blab 1978, 1986, Blab et al. 1984, Tiedemann 1990). In Central Europe all amphibian species show severe population reductions and suffer loss of habitats. One of the most important reasons for the endangerment of amphibians is their strong reliance on aquatic as well as to terrestrial habitats. Reasons for population declines are intensive agri-