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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 6621

Enrique Martinez-Ansemil and Rut Collado; Distribution patterns of aquatic oligochaetes inhabiting watercourses in the Northwestern Iberian Peninsula. Hydrobiologia 334:73-83, 1996

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Distribution patterns of aquatic oligochaete assemblages, inhabiting largely unpolluted watercourses, in the Northwestern Iberian Peninsula, and their relationships with chemical and physiological characteristics were analyzed by means of multivariate analyses. Qualitative and quantitative samples from 47 stations were obtained seasonally during 1983/84 and 1988/90. The variables included in this study were altitude, order number, distance from the origin, mean width, mean depth, substrate, current velocity, oxygen content, pH, conductivity, alkalinity and concentration of different ions. From a chemical point of view, major changes in the structure of oligochaete assemblages were related to water mineralization. The correlation between faunal distribution and environmental variables showed a great increase when physiographic parameters were included in the analyses. Substrate type and current velocity are the principal variables explaining the community structure.