title: Species pools, community completeness and invasion: disentangling diversity effects on the establishment of native and alien species.
abstract: Invasion should decline with species richness, yet the relationship is inconsistent. Species richness, however, is a product of species pool size and biotic filtering. Invasion may increase with richness if large species pools represent weaker environmental filters. Measuring species pool size and the proportion realised locally (completeness) may clarify diversity-invasion relationships by separating environmental and biotic effects, especially if species' life-history stage and origin are accounted for. To test these relationships, we added seeds and transplants of 15 native and alien species into 29 grasslands. Species pool size and completeness explained more variation in invasion than richness alone. Although results varied between native and alien species, seed establishment and biotic resistance to transplants increased with species pool size, whereas transplant growth and biotic resistance to seeds increased with completeness. Consequently, species pools and completeness represent multiple independent processes affecting invasion; accounting for these processes improves our understanding of invasion.
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE-51005, Estonia.|Department of Biology, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, V1V 1V, Canada.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Bennett
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE-51005, Estonia.
authors.forename: Kersti
authors.initials: K
authors.lastname: Riibak
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE-51005, Estonia.
authors.forename: Ene
authors.initials: E
authors.lastname: Kook
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE-51005, Estonia.
authors.forename: Ülle
authors.initials: Ü
authors.lastname: Reier
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE-51005, Estonia.|Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Riin
authors.initials: R
authors.lastname: Tamme
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE-51005, Estonia.
authors.forename: C
authors.initials: C
authors.lastname: Guillermo Bueno
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE-51005, Estonia.
authors.forename: Meelis
authors.initials: M
authors.lastname: Pärtel
mesh_terms: D044822:Biodiversity; D065948:Grassland; D058865:Introduced Species; D010944:Plants / Q000145:classification* / Q000235:genetics*; D013045:Species Specificity
keywords: Alpha diversity; biotic resistance; competition; dark diversity; disturbance; exotic species; gamma diversity; invasibility; regional processes; structural equation modelling