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1

Effects of hydrological disturbance of different magnitude on riverine habitats and benthic invertebrates

Szczerkowska-Majchrzak E., Grzybkowska M.

Polish Journal of Ecology

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2015

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Vol. 63, nr 1

135--141

EN

Spates of different magnitude in a four order section of the lowland Drzewiczka River (central Poland) downstream from a dam reservoir and a wild-water slalom canoeing track (abbr. WCT) located just below the dam were studied. For over 20 years daily fluctuations enabling the training of canoeists induced a patchy mosaic of the riverbed, with five dominant habitats: pool, stagnant with emergent plants, submersed macrophyte, bank and riffle. Artificial floods, in September 2000, March 2001 and February 2002, were other flow events of this reach, thus the main aim of this paper is to assess the resistance of macroinvertebrates, measured as the relative lack of loss in density after floods. The three- (September) and five-fold (March) increased discharge in relation to the median affected the riverine environmental variables and caused the entrance into the water column and/or washing away of Ephemeroptera, Trichoptera and Simuliidae. In turn the highest-flow event (February, 16-fold flow increase) induced the instability of all bed patches. Oligochaeta, one of the dominant, inbenthic groups of passive drifters, were dragged along the bottom and then stopped by macrophytes. Meanwhile, chironomids, the second dominant benthic group, showed two kinds of behaviour patterns. Orthocladiinae, organisms prone to drift, were washed away after each flood; consequently the riffle and submersed macrophytes became partly depleted of them. Other midges, inbenthic Chironomini (Chironominae) with worse propensities to drift, were also washed out, except from deeper sediment layers, between the roots of macrophytes and in the bank habitat. Thus the macroinvertebrate assemblages in the Drzewiczka River have adapted to the moderate pulse disturbances, but their response to high flow events depends on the species’ traits.

2

Trace metal concentrations in free-ranger, tube-dweller chironomid larvae and a weakly polluted fluvial sediment

Grzybkowska M., Dukowska M., Michałowicz J., Leszczyńska J.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 4

445--455

EN

The objective of this study was to analyze macroinvertebrate assemblages dominated by Chironomidae (Diptera) and to assess the protective nature of these midges’ larval tubes against trace metals in the weakly polluted Bzura River. This low order lowland river flows through the Łódź City Municipal Area and is supplied by a large amount of organic matter from ecotones and a polluted roadside. Determination of metal content in sediments and chironomid tissue and tubes was conducted using atomic absorption spectroscopy. Our study has shown that the composition of chironomid assemblages was not determined by trace metals but rather by high organic enrichment, which caused the dominance of two species representing the same trophic group − gathering collectors − but differing in behavior. One of them belongs to free-rangers (Prodiamesa olivacea), while the other (Chironomus riparius) to tube-dweller larvae. Although the accumulation of certain trace metals in the tubes was found, the larvae of both types of behavior had a similar concentration of metals in their tissues, which proves effective metal detoxification in these insects.

3

Influence of natural organic matter and metal accumulation in sediment on riverine macrobenthic assemblages

Dukowska M., Michałowicz J., Grzybkowska M.

Polish Journal of Ecology

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2012

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Vol. 60, nr 2

351-362

EN

We have investigated trace metal accumulation in sediment and in insect larvae in a small lowland river, which is an ecosystem with a large load of organic allochthonous matter (leaf packs) due to its first stream order section running across forest as well as along the edge of a large city (anthropogenic enrichment). Two study sites of this reach are separated by recreation ponds. Mean annual discharge at the upstream site (BZA) was below 0.010 m3 s[^-1], while at downstream one (BZB) it increased to 0.037 m3 s[^-1], the latter flow highly fluctuating. Riverbed at BZA consisted of sand and cobbles, while at BZB of different fractions of sand (substrate inorganic index, SI, significantly lower). Beside benthic samples obtained at monthly intervals over a year, additional samples were collected three times over the year: in winter, late spring, and autumn from each site to get organisms (insect larvae) and sediment for metal analysis. Two species representing chironomids (Chironomus riparius and Prodiamesa olivacea) and one ephemeropterans (Ephemera danica) were selected for detailed analysis. Despite these three taxa being different in terms of morphology and/or physiology they belonged to the same functional feeding group, i.e. sediment feeders. We avoided species occurring in food chains in which sediment indirectly affected organisms. Correlations between metal concentrations in these aquatic organisms and their environments were recorded at the analysed sites. Higher index values of metal bioaccumulation (bioconcentration factor, BCF) by insects were obtained at the downstream site (BZB), with relatively low levels of toxicants. For example, 8.5 for Zn (in spring), 23.0 for Pb, 3.3 for Ni and 39.5 for Cd (last three values in autumn); each of them was characteristic for P. olivacea. In turn, for the ephemeropteran species E. danica the respective highest BCF values were: 4.8 for Cu (in spring) and 1.6 for Mn (in autumn). On the other hand, lower BCF indices we gained at the BZA site, where higher concentrations of metals in sediment were recorded; for example, 2.7 for Zn (in autumn, P. olivacea), 4.3 for Pb, 6.8 for Cd, 4.3 for Cu (each value in spring, C. riparius). An exception of this relation was 5.6 for Ni (C. riparius, in autumn), and 1.8 for Mn (C. riparius, in spring) where BCF reached higher values at BZA than at BZB. Note that C. riparius did not appear at BZA during the studied period. Despite this species. absence the above mentioned relation may testify to the ability of sediment feeders to regulate metal contaminant content in their tissues. It seems that natural organic load rather than low levels of metal toxicants decided about macroinvertebrate assemblages in the study river.

4

Percid occupation of submersed riverine macrophytes: food resource partitioning between perch (Perca fluviatilis L.) and ruffe (Gymnocephalus cernuus L.)

Dukowska M., Grzybkowska M., Lik J., Jurasz W.

Oceanological and Hydrobiological Studies

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2012

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Vol. 41, No. 1

12-23

EN

In a reservoir tailwater of the large, lowland Warta River, perch and ruffe coexist in a macrophyte habitat, which develops as a result of low water discharge in the late spring and summer. At the beginning of each year the diet of both percids, when shorter than 100 mm, is dominated by large, benthic Hydropsyche. Later in the year, epiphytic Chironomidae and Simuliidae replace these trichopterans in the perch diet, and benthic Chironomidae replace them in the ruffe diet. Large cladoceran species then become accessory food items for perch. Consequently, the food niche overlap of these two percids during the research period is only marginal.

5

The food preferences of three-spined stickleback, Gasterosteus aculeatus L., downstream from a dam reservoir

Dukowska M., Grzybkowska M., Marszał L., Zięba G.

Oceanological and Hydrobiological Studies

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2009

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Vol. 38, No.2

39-50

EN

Submersed plants appeared in the impounded section of the Warta River as a consequence of low discharge in summer and were colonized by epiphytic fauna dominated by Hydra sp., Simuliidae, and Chironomidae. The three-spined stickleback consumed it voraciously, and their diet composition closely reflected the available food resources. In May their alimentary tracts were filled with Cladocera drifting from the reservoir, and then by the dominant taxa associated with macrophytes, especially chironomid periphyton scrapers. A comparison of dipteran head capsule width in the food resources and in the alimentary tract proved the three-spined stickleback preference for the largest larvae (optimal foraging strategy).

6

Distribution of ephemeropteran nymphs associated with different stolon sections of Eichhornia azurea (Schwartz) in two floodplain lakes of the Upper Parana River (Brazil)

Melo S. M. de, Takeda A. M., Grzybkowska M., Monkolski A.

Polish Journal of Ecology

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2004

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Vol. 52, nr 3

369-376

EN

Eichhornia azurea (Schwartz) Kunth is one of the most abundant species of aquatic macrophyte in the Upper Parana River floodplain, and ephemeropteran nymphs frequently inhabit this plant. The objective of this study was to analyze the distribution of ephemeropteran nymphs associated with three sections (apical, intermediate, and basal) of E. azurea in two floodplain lakes of the Upper Parana River as well as to establish the relation of this distribution to biotic and abiotic factors. The samplings of apical, intermediate and basal sections of E. azurea were carried out monthly from October 1997 to October 1998. Higher concentration of dissolved oxygen may contribute to greater density of nymphs on the apical plant segments near the water surface. Callibaetes willineri was the most abundant taxon, occuring on the apical and intermediate plant sections whereas Campsurus spp. were recorded on the basal and intermediate sections of the plant, near the sediment and, mainly during high water. Lower dissolvedoxygen concentrations near the lake bottom during the high water phase might suggest that during this phase the nymphs of Campsurus violaceus also migrate to E. azurea roots. It was found that changes in water level influenced the variation of the abundance of nymphs. Other genera, such as Tricorythodes and leptohyphes, were recorded during the high water phase, when river water enters the lakes and their shores are flooded.

7

Impact of the dam reservoir on river macrobenthic community : long-term study of Jeziorsko Reservoir and the Warta River in central Poland

Grzybkowska M., Dukowska M.

Polish Journal of Ecology

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2001

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Vol. 49, nr 3

243-259

EN

The riverine faunal responses was shown in relation to environmental changes arising from flow regulations in the Warta River downstream of the man-made Jeziorsko Reservoir. Two study sites were chosen for studies: one above the backwater (WAA) and the second in the tailwater (WAB) of the reservoir. The investigations were begun in 1988/1989 and repeated in the next three annual cycles: 1991/1992, 1992/1993 and 1995/1996. Chironomidae and Oligochaeta dominated in terms of density and biomass at both sites of the Warta River. At the beginning of the dam's functioning the pattern of macrobenthic spatial distribution was similar at both sites. But latter, in two last study summers water management resulted in a reduction of stream flows below their natural levels in the tailwater. These reductions in seasonal flow variability caused the greatest changes in biotic communities. Firstly the shoreline region in the tailwater enlarged and contracted in response to dam operations; the bottom was sometimes stranded (exposure to air) thus many macrobenthic groups were eliminated. Secondly Cladophora glomerata and macrophytes that developed in habitat several meters from the banks appeared to be responsible for substantial increase in abundance, especially of orthoclad midges. Additionally the retention of FPOM due to filtration by a dense bed of macrophytes created favourable conditions for pelophilus taxa, large sized taxa of Chironomini. Finally these mechanisms in opposite tendencies equalled - chironomids reached similar density in the backwater and tailwater.