title: Environmental drivers of ectomycorrhizal communities in Europe's temperate oak forests.
abstract: Ectomycorrhizal fungi are major ecological players in temperate forests, but they are rarely used in measures of forest condition because large-scale, high-resolution, standardized and replicated belowground data are scarce. We carried out an analysis of ectomycorrhizas at 22 intensively monitored long-term oak plots, across nine European countries, covering complex natural and anthropogenic environmental gradients. We found that at large scales, mycorrhizal richness and evenness declined with decreasing soil pH and root density, and with increasing atmospheric nitrogen deposition. Shifts in mycorrhizas with different functional traits were detected; mycorrhizas with structures specialized for long-distance transport related differently to most environmental variables than those without. The dominant oak-specialist Lactarius quietus, with limited soil exploration abilities, responds positively to increasing nitrogen inputs and decreasing pH. In contrast, Tricholoma, Cortinarius and Piloderma species, with medium-distance soil exploration abilities, show a consistently negative response. We also determined nitrogen critical loads for moderate (9.5-13.5 kg N/ha/year) and drastic (17 kg N/ha/year) changes in belowground mycorrhizal root communities in temperate oak forests. Overall, we generated the first baseline data for ectomycorrhizal fungi in the oak forests sampled, identified nitrogen pollution as one of their major drivers at large scales and revealed fungi that individually and/or in combination with others can be used as belowground indicators of environmental characteristics.
authors.affiliation: Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, UK; Imperial College London, London, SW7 2AZ, UK.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Suz
authors.forename: Nadia
authors.initials: N
authors.lastname: Barsoum
authors.forename: Sue
authors.initials: S
authors.lastname: Benham
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Dietrich
authors.forename: Karl Dieter
authors.initials: KD
authors.lastname: Fetzer
authors.forename: Richard
authors.initials: R
authors.lastname: Fischer
authors.forename: Paloma
authors.initials: P
authors.lastname: García
authors.forename: Joachim
authors.initials: J
authors.lastname: Gehrman
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Kristöfel
authors.forename: Miklós
authors.initials: M
authors.lastname: Manninger
authors.forename: Stefan
authors.initials: S
authors.lastname: Neagu
authors.forename: Manuel
authors.initials: M
authors.lastname: Nicolas
authors.forename: Jan
authors.initials: J
authors.lastname: Oldenburger
authors.forename: Stephan
authors.initials: S
authors.lastname: Raspe
authors.forename: Gerardo
authors.initials: G
authors.lastname: Sánchez
authors.forename: Hans Werner
authors.initials: HW
authors.lastname: Schröck
authors.forename: Alfred
authors.initials: A
authors.lastname: Schubert
authors.forename: Kris
authors.initials: K
authors.lastname: Verheyen
authors.forename: Arne
authors.initials: A
authors.lastname: Verstraeten
authors.forename: Martin I
authors.initials: MI
authors.lastname: Bidartondo
mesh_terms: D005060:Europe; D065928:Forests; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000502:physiology*; D009584:Nitrogen / Q000737:chemistry; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology; D029963:Quercus / Q000382:microbiology*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D014197:Trees / Q000382:microbiology
chemical_list: D012987:Soil; D009584:Nitrogen
keywords: ICP Forests; Quercus; bioindicator; critical load; exploration type; mycorrhizas; pollution