M. PAUNOVIĆ¹, DUNJA JAKOVČEV-TODOROVIĆ¹, V. SIMIĆ², BOJANA STOJANOVIĆ¹ and ANA VELJKOVIĆ²

¹Siniša Stanković Institute for Biological Research, 142 Despota Stefana Blvd.,11060 Belgrade, Serbia and Montenegro ²Institute of Biology and Ecology, Faculty of Science, University of Kragujevac, 34000 Kragujevac, Serbia and Montenegro

Abstract - The mayfly (Ephemeroptera) fauna was studied during investigations of the Vlasina River (Serbia) conducted in 1996. Twenty-six species from 14 genera belonging to eight families were recorded. Compared to similar aquatic ecosystems in Serbia and Europe, the ephemeropteran fauna of the Vlasina River is characterized by high species diversity. Good water quality and habitat heterogeneity led to the observed richness of taxa. Based on fauna distribution, the middle reach of the river can be divided into three different segments - upper, middle, and lower. Distribution of the two dominant families, Heptageniidae and Baetidae, is emphasized. Representatives of Baetidae reach their highest density in July, while Heptageniidae were the most abundant in November. The recorded mayflies represent widely distributed European or Holarctic species.