title: A strong species-area relationship for eukaryotic soil microbes: island size matters for ectomycorrhizal fungi.
abstract: While the effects of habitat size and isolation have been successfully studied for macro-organisms, there is currently debate about their relative importance in explaining patterns of microbial species richness. In this study, we examine the species richness of a dominant group of eukaryotic soil microbes, ectomycorrhizal fungi, on 'tree islands' of constant age and host composition that range in size from < 10 to > 10,000 m(2). Our results show that ectomycorrhizal species richness is significantly reduced on smaller and more isolated tree islands, and the species-area slope that we observe (0.20-0.23) is similar to average slopes reported for macro-organisms. Additionally, species' occurrence patterns across tree islands and investment trends in fungal fruit bodies suggest that a trade-off between competition and dispersal could play an important role in structuring ectomycorrhizal assemblages.
authors.affiliation: Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, California 94720, USA. kpeay@nature.berkeley.edu
authors.forename: Kabir G
authors.initials: KG
authors.lastname: Peay
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Bruns
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kennedy
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Bergemann
authors.forename: Matteo
authors.initials: M
authors.lastname: Garbelotto
mesh_terms: D005843:Geography; D038821:Mycorrhizae / Q000502:physiology*; D012988:Soil Microbiology; D013045:Species Specificity