Authors: T Boll L S Johansson T L Lauridsen F Landkildehus T A Davidson M Søndergaard F Ø Andersen E Jeppesen
Publish Date: 2012/02/03
Volume: 686, Issue: 1, Pages: 135-145
Abstract
Change in the abundance of benthic macroinvertebrates and the stable isotope composition C N of benthic invertebrates and zooplankton in Lake Vaeng Denmark was investigated over an 18year period following biomanipulation removal of cyprinids During the first nine years after biomanipulation the lake was clear and submerged macrophytes were abundant after this period a shift occurred to low plant abundance and high turbidity Two years after the biomanipulation total density of benthic macroinvertebrates reached a maximum of 17042 ±2335 SE individuals m−2 and the density was overall higher when the lake was in a clear state Redundancy analysis RDA suggested macrophyte abundance and total nitrogen TN concentration were the dominant structuring forces on the benthic macroinvertebrate assemblage Stable isotope analysis revealed that δ13C of macroinvertebrates and zooplankton was markedly higher in years with high submerged macrophyte abundance than in years without macrophytes most likely reflecting elevated δ13C of phytoplankton and periphyton mediated by a macrophyteinduced lowering of lake water CO2 concentrations We conclude that the strong relationship between macrophyte coverage and δ13C of macroinvertebrates and cladocerans may be useful in paleoecological studies of past changes in the dynamics of shallow lakes as change in macrophyte abundance may be tracked by the δ13C of invertebrate remains in the sedimentValuable technical assistance in the field and laboratory was provided by late Jane StougaardPedersen Lissa Skov Hansen Birte Laustsen Karina Jensen and Kirsten Landkildehus Thomsen We also thank Søren Erik Larsen for statistical advice Anne Mette Poulsen for editorial assistance and Tinna Christensen for layout assistance We also thank the anonymous reviewers for giving useful suggestions to improve this article The study was supported by the Danish Centre for Lake Restoration CLEAR—a Villum Kann Rasmussen Centre of excellence project EU REFRESH and EU WISER CRES and the Research Council for Nature and Universe 272080406
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