caa a22 4500 463168216 CHVBK 20180406164805.0 cr unu---uuuuu 170326e20070401xx s 000 0 eng 10.1007/s10530-006-9028-2 doi (NATIONALLICENCE)springer-10.1007/s10530-006-9028-2 Indirect food web effects of Bythotrephes invasion: responses by the rotifer Conochilus in Harp Lake, Canada [Elektronische Daten] [Jonathan Hovius, Beatrix Beisner, Kevin McCann, Norman Yan] As a recent invader of North American lakes, Bythotrephes longimanus has induced large changes in crustacean zooplankton communities through direct predation effects. Here we demonstrate that Bythotrephes can also have indirect food web effects, specifically on rotifer fauna. In historical time series data, the densities of the colonial rotifer Conochilus unicornis significantly increased after Bythotrephes invasion in Harp Lake, Ontario. No such changes were observed in a non-invaded reference lake, the nearby Red Chalk Lake. Evidence for two mechanisms explaining the Conochilus increase was examined based on changes to the crustacean zooplankton community over time. Rapid and severe declines in several herbivorous species of cladoceran zooplankton after Bythotrephes detection indicated a decrease in exploitative competition pressure on Conochilus. Secondly, a later and significant decline to virtual extinction of native invertebrate predators (Mesocyclops and Leptodora) could account for the observed Conochilus increase which also began 1-2years after invasion by Bythotrephes. Ultimately, it appears that both reduced competition followed by a loss of native invertebrate predators were necessary to lead to the large Conochilus densities observed following invader establishment. From this analysis of long-term community data, it appears that Bythotrephes has important indirect, as well as direct, food web effects in newly invaded North American lakes with implications for trophic relationships. Springer Science+Business Media B.V., 2006 Bythotrephes nationallicence Conochilus nationallicence Harp Lake nationallicence Rotifers nationallicence Competition nationallicence Predation nationallicence Zooplankton nationallicence Indirect effects nationallicence Hovius Jonathan Department of Integrative Biology, University of Guelph, N1G 2W1, Guelph, ON, Canada aut Beisner Beatrix Department of Biological Sciences, University of Quebec at Montreal, Case postale 8888, Succ. Centre-Ville, H3C 3P8, Montreal, QC, Canada aut McCann Kevin Department of Integrative Biology, University of Guelph, N1G 2W1, Guelph, ON, Canada aut Yan Norman Department of Biology, York University, M3J 1P3, Toronto, Canada aut Biological Invasions Kluwer Academic Publishers 9/3(2007-04-01), 233-243 1387-3547 9:3<233 2007 9 10530 https://doi.org/10.1007/s10530-006-9028-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10530-006-9028-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hovius Jonathan Department of Integrative Biology, University of Guelph, N1G 2W1, Guelph, ON, Canada aut NATIONALLICENCE 700 1- Beisner Beatrix Department of Biological Sciences, University of Quebec at Montreal, Case postale 8888, Succ. Centre-Ville, H3C 3P8, Montreal, QC, Canada aut NATIONALLICENCE 700 1- McCann Kevin Department of Integrative Biology, University of Guelph, N1G 2W1, Guelph, ON, Canada aut NATIONALLICENCE 700 1- Yan Norman Department of Biology, York University, M3J 1P3, Toronto, Canada aut NATIONALLICENCE 773 0- Biological Invasions Kluwer Academic Publishers 9/3(2007-04-01), 233-243 1387-3547 9:3<233 2007 9 10530 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer