ORIGINAL RESEARCH
The Effect of Stream Bed Morphology
on Shredder Abundance and Leaf-Litter
Decomposition in Hungarian Midland Streams
Kata Kovács1, Géza B. Selmeczy1, Tamás Kucserka1,
Nassr-Allah H. Abdel-Hameid2, Judit Padisák1
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1Department of Limnology, University of Pannonia, Veszprém, Egyetem utca 10. H-8200, Hungary
2Department of Zoology, Benha University, Egypt
Pol. J. Environ. Stud. 2011;20(6):1547-1556
KEYWORDS
ABSTRACT
The aim of this study was to examine the differences between natural and morphologically modified
stream bed sections in Hungarian midland streams by means of macroinvertebrate shredder abundance and
leaf litter decomposition, and identify the key drivers of poor shredder fauna in modified water bodies. Eight
sampling sites on three low order Hungarian watercourses were selected and studied between the springs of
2008 and 2009. Three types of leaf litter were collected and placed into leaf litter bags that were fixed to a
metal wire net on the bottom of the river bed. Samples were taken in every four weeks. Leaf litter content and
decomposition rate was determined and macroinvertebrates identified. Gammaridae dominated among shredders
and their proportion did not differ significantly in bags. The shredders’ counts and the leaf litter decay
rates were different in the experimental streams. The sampling sites located in modified stream sections, with
limited availability of food, exhibited lower shredder densities but higher decomposition rates (k>0.01 d-1) than
those observed in sites of undisturbed bed morphology with rich allochtonous organic matter (k<0.0077 d-1).
However, no significant differences were obtained in decay rates among the leaf species. Our results suggest
that shoreline vegetation and bed morphology are two equally important factors in determining functional
properties of streams; and leaf litter decomposition rate is not only a function of shredder density. Thus decomposition
rate can be an important functional variable for ecological status assessment of the water.