Investigations on benthic and drifting macroinvertebrates in the River Tisza

摘要

River Tisza has the most extreme fluctuating runoff in Hungary, alternating between low water levels in summer and winter an'd high water levels in spring and sometimes autumn. Especially high water level fluctuation characterizes the Hungarian reach of the Upper-Tisza; for example in 2003 the minimum water level was -235 cm and the maximum was 650 cm. In the most extreme cases the difference between the minimum and maximum water level can reach about 10 m. Extreme seasonal changes in the water velocity conditions also occur. The highly variable hydro-logical conditions determine the spatial and temporal distribution and the dispersal of macroinvertebrates, or rather the colonization of the benthic habitats (Buskens Moller Pillot 2000, Coffman 1989, Doisy Rabeni 2001, Matthaei et al. 1997, Townsend Hildrew 1976).