title: Hierarchical neighbor effects on mycorrhizal community structure and function.
abstract: Theory predicts that neighboring communities can shape one another's composition and function, for example, through the exchange of member species. However, empirical tests of the directionality and strength of these effects are rare. We determined the effects of neighboring communities on one another through experimental manipulation of a plant-fungal model system. We first established distinct ectomycorrhizal fungal communities on Douglas-fir seedlings that were initially grown in three soil environments. We then transplanted seedlings and mycorrhizal communities in a fully factorial experiment designed to quantify the direction and strength of neighbor effects by focusing on changes in fungal community species composition and implications for seedling growth (a proxy for community function). We found that neighbor effects on the composition and function of adjacent communities follow a dominance hierarchy. Specifically, mycorrhizal communities established from soils collected in Douglas-fir plantations were both the least sensitive to neighbor effects, and exerted the strongest influence on their neighbors by driving convergence in neighbor community composition and increasing neighbor seedling vigor. These results demonstrate that asymmetric neighbor effects mediated by ecological history can determine both community composition and function.
authors.affiliation: Department of Biology Stanford University Stanford California 94305; Ecology Evolution & Marine Biology University of California Santa Barbara California 93106; Present address: Woods Hole Oceanographic Institution 266 Woods Hole Road, Mail Stop 52 Woods Hole Massachusetts 02543.
authors.forename: Holly V
authors.identifier: 0000-0002-9335-0039
authors.initials: HV
authors.lastname: Moeller
authors.affiliation: Bio-Protection Research Centre Lincoln University Lincoln 7640 New Zealand.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Dickie
authors.affiliation: Landcare Research Lincoln 7640 New Zealand.
authors.forename: Duane A
authors.initials: DA
authors.lastname: Peltzer
authors.affiliation: Department of Biology Stanford University Stanford California 94305.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Fukami
keywords: Community assembly; community coalescence; community dynamics; compositional variation; ecosystem function; ectomycorrhizal fungi; plant–fungal interactions