Species composition, spatial distribution and temporal occurrence of mayflies (Ephemeroptera) in the Vlasina river (southeast Serbia)

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.Raznovrsnost efemeroptera proučavana je u reci Vlasini (Srbija) tokom 1996. godine. Dvadeset šest vrsta iz četrnaest rodova utvrđeno je tokom ove obimne studije. U poređenju sa sličnim akvatičnim ekosistemima u Srbiji i Evropi, fauna efemeroptera iz reke Vlasine karakteriše se visokom raznolikošću vrsta. Dobar kvalitet vode i raznovrsnost staništa uslovljavaju i uočeno bogatstvo taksona. Središnji deo reke može se podeliti u tri segmenta - gornji, srednji i donji. Sagledana je distribucija predstavnika dve dominantne porodice Heptageniidae i Baetidae. Predstavnici baetida dostižu najveću gustinu tokom jula, a heptagenida u novembru. Utvrđene vrste efemeroptera predstavljaju evropske ili holarktičke elemente.nul