title: Planktonic ciliate community structure in shallow lakes of lowland Western Europe.
abstract: Temperate shallow meso- to eutrophic lakes can exist in one of two alternative states with contrasting foodwebs, referred to as the clear-water and the turbid state. We describe the planktonic ciliate communities of such lakes based on a survey of 66 northwestern European lakes. Ciliates were enumerated and identified to species level according to the quantitative protargol staining technique. Ciliate biomass was on average twice as high in the turbid than in the clear-water lakes. The ciliate communities were dominated by oligotrichs and protostomatids, and no differences in functional composition or α-diversity could be detected between turbid and clear-water lakes, although β-diversity tended to be higher in the latter. At the species level, however, community structure strongly differed between turbid and clear-water lakes, and several indicator species could be identified for the different lake categories. Variation partitioning showed that nutrient status did not explain ciliate community structure independent of the alternative states, while lake area was identified as an additional structuring factor for the ciliate communities. These results stress the importance of the ecosystem structure in shaping ciliate communities in temperate shallow lakes and suggest that nutrient status has little direct effect on ciliate community structure in such lakes.
authors.affiliation: Laboratory of Protistology and Aquatic Ecology, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium. Electronic address: jeroen.vanwichelen@UGent.be.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Van Wichelen
authors.forename: Liselotte S
authors.initials: LS
authors.lastname: Johansson
authors.forename: Pieter
authors.initials: P
authors.lastname: Vanormelingen
authors.forename: Steven A J
authors.initials: SA
authors.lastname: Declerck
authors.forename: Torben L
authors.initials: TL
authors.lastname: Lauridsen
authors.forename: Luc
authors.initials: L
authors.lastname: De Meester
authors.forename: Erik
authors.initials: E
authors.lastname: Jeppesen
authors.forename: Wim
authors.initials: W
authors.lastname: Vyverman
mesh_terms: D044822:Biodiversity; D016798:Ciliophora / Q000502:physiology*; D017753:Ecosystem; D005060:Europe; D060106:Lakes / Q000469:parasitology*; D010933:Plankton / Q000469:parasitology*
keywords: Community structure; Indicator species; Lowland Europe; Planktonic ciliates; Shallow lakes; Stable states