EFFECTS OF INVERTEBRATE PREDATION ON THE SEASONAL SUCCESSION OF A ZOOPLANKTON COMMUNITY - A 2 YEAR STUDY IN LAKE AYDAT, FRANCE

Direct observations on living animals, examination of gut contents, spatio-temporal distribution analysis, demographic data and a two year comparative study of zooplankton population dynamics illustrate the importance of invertebrate predation on the seasonal succession of the zooplankton in Lake Aydat, Central Massif, France. Three invertebrate predators living in this eutrophic lake contribute to regulate the populations' development. The rotifer Asplanchna priodonta exerts a predation pressure on Keratella cochlearis, Polyarthra remata and P. dolichoptera. The copepod Cyclops vicinus vicinus exerts a predation pressure on the latter two rotifer species. The larvae of the Dipteran Chaoborus cristallinus consumes A. priodonta, Kellicottia longispina, B. longirostris, D. longispina, C. quadrangula and ovigerous females of C. vicinus vicinus. We also hypothesize that adults of Acanthodiaptomus denticornis, which consume large ciliates in this lake, contribute to the rotifer decline at the end of summer. The interactions between invertebrate predators and their preys are reflected in quantitative changes in community dynamics. © 1990 Kluwer Academic Publishers.