title: Above- and below-ground effects of plant diversity depend on species origin: an experimental test with multiple invaders.
abstract: Although many plant communities are invaded by multiple nonnative species, we have limited information on how a species' origin affects ecosystem function. We tested how differences in species richness and origin affect productivity and seedling establishment. We created phylogenetically paired native and nonnative plant communities in a glasshouse experiment to test diversity-productivity relationships and responsible mechanisms (i.e. selection or complementarity effects). Additionally, we tested how productivity and associated mechanisms influenced seedling establishment. We used diversity-interaction models to describe how species' interactions influenced diversity-productivity relationships. Communities with more species had higher total biomass than did monoculture communities, but native and nonnative communities diverged in root : shoot ratios and the mechanism responsible for increased productivity: positive selection effect in nonnative communities and positive complementarity effect in native communities. Seedling establishment was 46% lower in nonnative than in native communities and was correlated with the average selection effect. Interspecific interactions contributed to productivity patterns, but the specific types of interactions differed between native and nonnative communities. These results reinforce findings that the diversity-productivity mechanisms in native and nonnative communities differ and are the first to show that these mechanisms can influence seedling establishment and that different types of interactions influence diversity-productivity relationships.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN, 37996-1610, USA.
authors.forename: Sara E
authors.initials: SE
authors.lastname: Kuebbing
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN, 37996-1610, USA.|Natural History Museum of Denmark, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Aimée T
authors.initials: AT
authors.lastname: Classen
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN, 37996-1610, USA.|Center for Macroecology, Evolution and Climate, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: Sanders
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN, 37996-1610, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Simberloff
mesh_terms: D018533:Biomass; D058865:Introduced Species; D010802:Phylogeny; D018517:Plant Roots / Q000254:growth & development*; D018520:Plant Shoots / Q000254:growth & development*; D010944:Plants
keywords: below-ground productivity; biodiversity-ecosystem function; co-occurring nonnatives; invasion impact; old field; selection effect