5 Folia Fac. Sci. Nat. Univ. Masarykianae Brunensis, Biológia 102 (1999)_______ Contents: Kubíček F., Helešic J., Vojtíškova D. & Zahrádková S.: The impact of the Vranov reservoir hydropower station operation on the bottom biota of the Dyje River (Czech Republic).................................7 Komárek O. & Marvan P.: The influence of the Vranov reservoir hydropower station operation on phytobenthos in the Dyje River (Czech Republic)....................................95 Opravilová V. & Komárek O.: The micro - meiozoobenthic communities in torrential zone of the Dyje River influenced by hydropeaking................................................................ 115