Blackfly assemblages (Diptera, Simuliidae) of the Carpathian river: habitat characteristics, longitudinal zonation and eutrophication

Abstract

Investigations were carried out in 2003-04 within a project on trend biomonitoring of macrozoobenthos in the Hron River system. They were focused on blackfly assemblages of the Hron River (Slovakia), using the distribution patterns of blackflies (18 species) from 14 sites, representing a fluent transition from epirithral to epipotamal. Two main ''sister'' groups were distinguished using TWINSPAN analysis. Prosimulium rufipes is an indicator species within the first group. This group typically occurs in the zone representing a part of the river upstream and its tributaries. Simulium lineatum is an indicator species within the second group that occurs in the zone representing the middle and lower part of the river. The Upstream-Downstream gradient represents, in fact, the ecological position (EP) of the studied localities of the Hron River along the River Continuum Concept. The distribution fitting analysis divides the distribution amplitude data of blackfly species into three sets of nonoverlaping intervals: (1) 0.00-0.19 stenotopic (P. rufipes in the upper course of the river, Simulium erythrocephalum in the lower course of the river), (2) 0.20-0.39 mesotopic (Simulium argyreatum, S. equinum-hyporhithral) and (3) 0.40-0.50 eurytopic (Simulium reptans, S. variegatum). According to CCA the most important variables correlated with the first axis, and were linked to the nitrate and maximal water temperature which gradually increase from the upper stretch of the river.

Biological zonation of the last unbound big river in the West Carpathians: reference scheme based on caddisfly communities

“…For these reasons, we tried to delineate distinct biotic zones of the Hron River and used caddisfly species as indicators of those zones. Along with the results provided elsewhere (Bitušík et al, 2006;Krno, 2007;Illéšová et al, 2008) we obtained important information on predisturbance longitudinal patterns in benthic assemblages of the Hron River. Dams affect the sediment dynamics and distribution, dispersal, and abundance of benthic macroinvertebrates and other aquatic organisms (Stanford et al, 1996;Kiraly et al, 2014).…”

“…All of the lower section of the river can be classified as epipotamal. Previous efforts to distinguish discrete zones of the Hron River based on chironomids (Bitušík et al, 2006) and blackflies (Illéšová et al, 2008) revealed slightly different schemes (Figure 6). The most apparent change in caddisfly communities was observed at the river section where filtering caddisflies become dominant, probably mirroring changes in food supply.…”

Blackfly (Diptera, Simuliidae) communities and species richness estimation in Carpathian montane streams

“…Authors confirmed 16 species of blackflies at four sites. Illéšová et al found 9 species in Zubrovica stream [13], which belongs to investigated flows of our research as well. There were 11 species found in the upper section of the Hron River near Telgárt.…”

Effects of land use on black fly assemblages (Diptera: Simuliidae) in submontane rivers (West Carpathians, Slovakia)

“…Urbanization and agricultural land use affect the community structure and biodiversity of black flies (Adler et al 2004;Zhank et al 1998). Changes in species composition can indicate longitudinal zonation and eutrophication (Halgoš et al 2001;Illéšová et al 2008). Schreder & Waringer (2002) found that species richness of black flies in European streams increased with current velocity and the size of streambed particles.…”