Original scientific paper

Siltation disturbance in a mountain stream: aspect of functional composition of the benthic community

MARKO MILIŠA ; Department of Zoology, Division of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia
VESNA ŽIVKOVIĆ ; Department of Zoology, Division of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia
RENATA MATONIČKIN KEPČIJA ; Department of Zoology, Division of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia
IVAN HABDIJA ; Department of Zoology, Division of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia

Abstract

Background and Purpose: Siltation is a recognized stress for the benthic community. It may cause changes in the structure of habitat substrate and water physical and chemical properties. The aim of this study was to ascertain the effects of siltation on the function of a mountain stream benthic community, specifically in respect to availability of food resources.

Materials and Methods: The study was carried out at Bistra Stream on
theMedvednica Mountain in NWCroatia. Siltation was caused by quarrying. Samples were taken at a control (unsilted) site and three impact sites on four dates during the spring of 2006. Turbidity, water temperature, pH, oxygen content, conductivity and COD were measured and triplicate benthos samples were taken using a 30´30 cm Surber sampler on each sampling date. Impact of siltation on functional feeding guilds was analyzed.

Results and Conclusions: Turbidity, pH and temperature increased significantly downstream of the siltation source. Total number of individuals decreased by 85%, number of taxa by 60% and Shannon’s diversity index followed accordingly (by 56%). The grazers and the detritivores were proven to be most sensitive to the disturbance. The disturbance did not strongly affect shredders whereas predator abundance increased. We conclude that change in food availability is a crucial aspect of siltation disturbance and that allogenic siltation is more devastating because of the additional
chemical changes not noted during natural siltation.

Keywords

fine sediment; stress; FFG; benthos; macroinvertebrates; quarrying; mining; Croatia

Hrčak ID:

58144

URI

https://hrcak.srce.hr/58144

Publication date:

1.6.2010.

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