Abiotic features and macroinvertebrate colonization of the hyporheic zones of two tributaries of the river Elbe (Germany)

Abstract

Whole-ecosystem experiments may reach statistical pertinence when reference and treatment sites are compared. Therefore at least two similar systems must be found. To this aim we tried to answer the question if the hyporheic zones of both streams have similar features. We postulated that both streams would be unsuitable for a comparison in an ecosystem experiment if the structure of their hyporheic invertebrate communities differs significantly. Although pH, electrical conductivity and nitrate concentration differed in the surface water, variability of all chemical criteria studied in the hyporheic zones was much lower between the two streams compared to the variability within each stream. Thus the structure of both hyporheic invertebrate communities did not differ significantly. Because of this uniformity both streams are regarded to be suitable for a comparison in a whole-ecosystem experiment.