title: Change in soil fungal community structure driven by a decline in ectomycorrhizal fungi following a mountain pine beetle (Dendroctonus ponderosae) outbreak.
abstract: Western North American landscapes are rapidly being transformed by forest die-off caused by mountain pine beetle (Dendroctonus ponderosae), with implications for plant and soil communities. The mechanisms that drive changes in soil community structure, particularly for the highly prevalent ectomycorrhizal fungi in pine forests, are complex and intertwined. Critical to enhancing understanding will be disentangling the relative importance of host tree mortality from changes in soil chemistry following tree death. Here, we used a recent bark beetle outbreak in lodgepole pine (Pinus contorta) forests of western Canada to test whether the effects of tree mortality altered the richness and composition of belowground fungal communities, including ectomycorrhizal and saprotrophic fungi. We also determined the effects of environmental factors (i.e. soil nutrients, moisture, and phenolics) and geographical distance, both of which can influence the richness and composition of soil fungi. The richness of both groups of soil fungi declined and the overall composition was altered by beetle-induced tree mortality. Soil nutrients, soil phenolics and geographical distance influenced the community structure of soil fungi; however, the relative importance of these factors differed between ectomycorrhizal and saprotrophic fungi. The independent effects of tree mortality, soil phenolics and geographical distance influenced the community composition of ectomycorrhizal fungi, while the community composition of saprotrophic fungi was weakly but significantly correlated with the geographical distance of plots. Taken together, our results indicate that both deterministic and stochastic processes structure soil fungal communities following landscape-scale insect outbreaks and reflect the independent roles tree mortality, soil chemistry and geographical distance play in regulating the community composition of soil fungi.
authors.affiliation: Department of Biological Sciences, University of Alberta, B717a Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Pec
authors.affiliation: Department of Biological Sciences, University of Alberta, B717a Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada.|Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta, T6G 2E3, Canada.
authors.forename: Justine
authors.identifier: http://orcid.org/0000-0003-0497-1552
authors.initials: J
authors.lastname: Karst
authors.affiliation: Department of Biology, University of New Mexico, Castetter Hall 104, Albuquerque, NM, 87131, USA.
authors.forename: D Lee
authors.initials: DL
authors.lastname: Taylor
authors.affiliation: Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta, T6G 2E3, Canada.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Cigan
authors.affiliation: Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta, T6G 2E3, Canada.
authors.forename: Nadir
authors.initials: N
authors.lastname: Erbilgin
authors.affiliation: Department of Biological Sciences, University of Alberta, B717a Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada.
authors.forename: Janice E K
authors.initials: JE
authors.lastname: Cooke
authors.affiliation: Department of Forest and Conservation Sciences, University of British Columbia, Forest Sciences Centre #3601-2424 Main Hall, Vancouver, British Columbia, V6T 1Z4, Canada.
authors.forename: Suzanne W
authors.initials: SW
authors.lastname: Simard
authors.affiliation: Department of Biological Sciences, University of Alberta, B717a Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada.
authors.forename: James F
authors.initials: JF
authors.lastname: Cahill
mesh_terms: D000818:Animals; D044822:Biodiversity; D001517:Coleoptera / Q000502:physiology*; D004196:Disease Outbreaks; D005658:Fungi / Q000502:physiology*; D005843:Geography; D038821:Mycorrhizae / Q000502:physiology*; D010802:Phylogeny; D028223:Pinus / Q000382:microbiology* / Q000469:parasitology*; D010935:Plant Diseases / Q000382:microbiology / Q000469:parasitology; D012987:Soil; D012988:Soil Microbiology; D014197:Trees / Q000502:physiology
chemical_list: D012987:Soil
keywords: 
  Dendroctonus ponderosae
  ; 
  Pinus contorta
  ; biotic disturbance; community composition; geographical distance; next-generation sequencing; richness; soil fungi