title: Nonrandom seedling establishment corresponds with distance-dependent decline in mycorrhizal abundance in two terrestrial orchids.
abstract: In plant species that critically rely on mycorrhizal symbionts for germination and seedling establishment, distance-dependent decline of mycorrhizal fungi in the soil can be hypothesized to lead to significant spatial clustering as a result of nonrandom spatial patterns of seedling establishment. To test this hypothesis, we investigated the abundance and distribution of mycorrhizal fungi in the soil and how they relate to spatial patterns of adults and seedling recruitment in two related orchid species. We combined assessments of spatial variation in fungal abundance using quantitative PCR (qPCR) with spatial point pattern analyses based on long-term demographic data and cluster point process models. qPCR analyses showed that fungal abundance declined rapidly with distance from the adult host plants. Spatial point pattern analyses showed that successful recruitment in both species was clustered significantly around adult plants and that the decline in the neighborhood density of recruits around adults coincided with the decline of fungal abundance around adult plants. Overall, these results indicate that the distribution and abundance of fungal associates in the soil may have a strong impact on the aboveground distribution of its partner.
authors.affiliation: Department of Biology, Plant Conservation and Population Biology, KU Leuven, B-3001, Leuven, Belgium.|Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium.
authors.forename: Michael
authors.initials: M
authors.lastname: Waud
authors.affiliation: Department of Ecological Modelling, UFZ Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318, Leipzig, Germany.|German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Wiegand
authors.affiliation: Research Institute for Forest and Nature, Kliniekstraat 25, B-1070, Brussels, Belgium.
authors.forename: Rein
authors.initials: R
authors.lastname: Brys
authors.affiliation: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Lievens
authors.affiliation: Department of Biology, Plant Conservation and Population Biology, KU Leuven, B-3001, Leuven, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Jacquemyn
mesh_terms: D001530:Belgium; D038821:Mycorrhizae / Q000235:genetics / Q000502:physiology*; D029595:Orchidaceae / Q000254:growth & development* / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology; D036226:Seedlings / Q000254:growth & development*; D012988:Soil Microbiology
keywords: Mycorrhizae; Orchidaceae; Thomas processes; Tulasnellaceae; quantitative PCR (qPCR); seedling establishment; spatial point pattern analysis