Collembola in the Bed Sediments of an Alpine Gravel Stream (RITRODAT-Lunz Study Area,Austria)

In the creek “Oberer Seebach”, 355 springtails belonging to 42 species were collected from the water-filled pore space of the bed gravel proper and the adjacent bank sediment. Almost 10 % of 2094 samples contained Collembola, with a mean density of 1.8 specimens per positive sample. The topographic distribution of the most abundant species Lepidocyrtus lignorum, Agrenia bidenticulata, and Folsomia quadrioculata suggests that riparian and eurytopic forms are frequently washed into the channel and transported down to a considerable sediment depth without injury to the animals. The rising groundwater table in the bank sediment traps no riparian, but predominantly hemiedaphic species. Euedaphic springtails are rare, especially in the groundwater samples.