The role of the invertebrate predator Leptodora kindti in the trophic cascade of a lowland reservoir

Leptodora kindti is the dominant pelagic invertebrate predator of Sulejow R eservior. During summer, its abundance and large size (10-13 mm) significan tly contribute to the elimination of much filtering zooplankton. A quantita tive evaluation of the predator's dynamics was carried out with two samplin g techniques: a 5-l zooplankton sampler and a bongo net installed in front of a boat. Variability of the data obtained using the zooplankton sampler w as one order of magnitude higher than that from the bongo net. In midsummer (July), a high density (2360 ind m(-3)) of L. kindti coincided with a dist inct decrease in abundance of the dominant filtrator, Daphnia cucullata (fr om 111 000 to 19 000 ind m(-3)), confirmed by a positive correlation betwee n the number of D. cucullata eliminated by L. kindti and the death rate of D. cucullata in the pelagic zone.