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Diversity and distribution patterns of benthic insects in streams of the Aurès arid region (NE Algeria)

Ghougali Fayssal, Bachir Abdelkrim Si, Chaabane Nassima, Brik Imen, Medjber Rachid Ait, Rouabah Abdelhak

Oceanological and Hydrobiological Studies

2019

Vol. 48, No. 1

31--42

The objective of the present study was to document the knowledge about the biodiversity of benthic insect communities and their distribution patterns in the semi-arid bioclimatic stage in the streams of the Aurès Region (NE Algeria). The distribution patterns of communities were analyzed in relation to some environmental factors: physicochemical water parameters and global habitat characteristics, including human impact. The taxonomic biodiversity of six sampled streams (wadis) comprises 42 insect taxa, belonging to seven orders and 30 families, of which Coleoptera is the most diverse order (15 taxa), whereas Diptera, Trichoptera and Ephemeroptera dominate in terms of abundance. The human impact, flow velocity and some quality parameters of water (potential of hydrogen, nitrite, concentration of orthophosphates and conductivity) were identified as the most influential environmental variables, which allows the prediction of taxonomic diversity indicators. The classification and regression tree analysis (CART) for benthic insects shows the effect of environmental variables (habitat parameters and human impact in the arid region) on the diversity and distribution of insect orders. The RDA analysis showed that altitude, substrate type, human impact and physicochemical parameters of water (pH, flow velocity, conductivity and total dissolved solids) are the most important predictor variables that play an important role in the distribution patterns of benthic insects.

Comparative Effects of Aquaculture and Water Level Fluctuations on Macroinvertebrate Communities in Three Gorges Reservoir, China

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

Polish Journal of Ecology

2017

Vol. 65, nr 4

390--404

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).

Das eu- und hypokrenal harzer bache: Langzeituntersuchungen der wassertemperaturen, umgebungsfaktoren und ihre bedeutung fur die lebensgemeinschaft dieser gewasser

Muller A.

Studia Quaternaria

2004

Vol. 21

37-44

The water temperature of 14 springbrooks (Harz mountains, Northern Germany) were recorded by dataloggers over a period of 2 years. Additionally, some environmental parameters of these springs were observed. At some springbrooks, aquatic insects were caught with emergence traps. The water temperature of the eucrenal showed no variations over the time. But in the hypocrenal, we found fluktuations and a seasonal variation of the water temperature. It was possible to classify the springbrooks in groups with different annual temperature courses and biological productivities.