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Diversity and numbers of Oligochaeta against the background of other macroinvertebrates in a concrete bed of the River Widawka (Central Poland)

100%

Kahl K. , Golanska M.

Acta Hydrobiologica

1987

tom 29

nr 1

Comparative effects of aquaculture and water level fluctuations on macroinvertebrate communities in Three Gorges Reservoir, China

84%

Chi S. , Zheng Z. , Zhang Z. , Hu J. , Zheng J. , Zhao X. , Hu J. , Dong F. , Peng J.

2017

tom 65

nr 4

In this study, the comparative effects of the two disturbances (aquaculture and water level fluctuations) on macroinvertebrate communities were explored in two waterbodies connected with the reservoir system of Three Gorges Reservoir (TGR) in China. One water body called Gaoyang Bay which suffered organic pollution from intensive aquaculture. Another named Hanfeng Lake, where the effects of water-level fluctuations are obvious. The results showed that aquaculture could significantly affect the chemical forms of nutrients, decrease the α-diversity and increase the β-diversity of macroinvertebrates although the communities in the treatment area in Gaoyang Bay were not fundamentally changed comparing to the control area in the same bay. The densities of macroinvertebrates in the treatment area were significantly lower than that of the control area. The composition of functional feeding groups in the treatment area was close to that in Hanfeng Lake, but obviously different from that in the control area in Gaoyang Bay and the collectors and predators dominated the communities in this control area with the highest percentages. Although water-level fluctuations had negative effects on the communities by decreasing the α-diversity and increasing the β-diversity, which were confirmed by the values of Simpson index, Shannon-Wiener index and Harrison's index in the control area of Gaoyang bay and Hanfeng Lake, the adverse effects were relative low compared to aquaculture. In the bays of TGR, the small-scale disturbance (aquaculture activities) had more significant negative effects compared to the big-scale disturbance (water-level fluctuations related to dam operation of TGR).

The effect of dam reservoirs on oligochaete communities in the River Dunajec (Southern Poland)

84%

Dumnicka E.

Acta Hydrobiologica

1987

tom 29

nr 1

Effect of trial impoundment on downstream macroinvertebrate community during construction of a large dam

84%

Asaeda T. , Zaman T. , Takahashi Y.

tom 61

nr 4

The dam construction has substantial impacts on the downstream environment even from the beginning of construction stages. The stage of impounding water is supposed to have the largest effects on the downstream environment. Monthly observation was carried out during the trial impoundment of a large concrete dam, including water temperature, organic matter fluxes, epilithic chlorophyll a, and macroinvertebrate communities both at the upstream and the downstream water of the impoundment. Both before and after the impoundment, the epilithic chlorophyll a contents and fine particulate organic matter (FPOM) fluxes variations were insignificant. As the impoundment volume increased the downstream water temperature substantially increased in comparison to upstream water temperature. Coarse particulate organic matter (CPOM) fluxes (gDW/10min) in the downstream became lower than that of the upstream even with one day of retention period. Chironomidae, Stenopsychidae, Simuliidae, Tipulidae and Hydropsychidae substantially enhanced immediately after the impoundment started, whereas, Taeniopterygidae and Chloroperlidae were declined. It was evident that the trial impoundment has a substantial effect on the downstream biota even from the low volume of water.

Riparian vegetation of streams and the macroinvertebrate community structure

67%

Bis B. , Higler L. W. G.

nr 1-2

Riparian vegetation is a typical ecotone by its structural and functional position between the terrestial part of the watershed and the stream (Naiman, Decamps 1990). In consequence, the riparian zone forming an integrated component of stream ecosystems significantly determines the aquatic community. Macroinvertebrates are affected by defined variability of environmental factors. In streams under canopy: light access is reduced; summer temperatures are lower; shed leaves form the main source of energy; insects falling from the vegetation into the water create another source of food; roots from trees form shelter and strongly influence hydraulic patterns. As a result, many (micro) habitats can exist and persist. The relationships between the covered percentage of the riparian zone, hydraulic processes, POM retention and macroinvertebrate functional organization was analyzed. Riparian vegetation forms a buffer zone in agricultural landscape and thus prevents inflow of nutrients, but also of fine sediments. Clearing of riparian vegetation changes all these conditions, resulting in a totally different and less varied biocommunity. Examples are given from Poland and The Netherlands.