Distribution and diversity of aquatic Oligochaeta in small streams of the middle taiga


Abstract: The goal of the present study was to describe the fauna, community structure, distribution, diversity, abundance, and ecology of Oligochaeta in small streams of the Komi Republic. The work was performed in 13 streams located in the Vychegda River basin during the month of July, 2005-2008. During the study, 48 taxa from 7 families were collected. The habitat of each study stream was determined with respect to chemical water composition (Na^+, Mg^{2+}, Ca^{2+}, Cl^-, and total phosphorus (P^{tot}), among others) and some environmental factors: bottom structure (hard or soft), water temperature, depth, flow velocity, moss or algae cover, etc. The species composition, diversity, and determination of the small streams' aquatic Oligochaeta as well as the influence of different ecological factors on these characteristics were analyzed and discussed. The number of species, their composition, and the average abundance and biomass of Oligochaeta were found to depend upon bottom texture, current velocity, moss or algae cover, water temperature, and changes in the water chemicals (Na^+, Mg^{2+}, and P^{tot} concentrations), as well as the nitrogen, carbon, and humus contents in the bottom sediments.

Keywords: Oligochaeta, zoobenthos, ecology of northern fresh water streams

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