title: Local dominance of exotic plants declines with residence time: a role for plant-soil feedback?
abstract: Recent studies have shown that introduced exotic plant species may be released from their native soil-borne pathogens, but that they become exposed to increased soil pathogen activity in the new range when time since introduction increases. Other studies have shown that introduced exotic plant species become less dominant when time since introduction increases, and that plant abundance may be controlled by soil-borne pathogens; however, no study yet has tested whether these soil effects might explain the decline in dominance of exotic plant species following their initial invasiveness. Here we determine plant-soil feedback of 20 plant species that have been introduced into The Netherlands. We tested the hypotheses that (i) exotic plant species with a longer residence time have a more negative soil feedback and (ii) greater local dominance of the introduced exotic plant species correlates with less negative, or more positive, plant-soil feedback. Although the local dominance of exotic plant species decreased with time since introduction, there was no relationship of local dominance with plant-soil feedback. Plant-soil feedback also did not become more negative with increasing time since introduction. We discuss why our results may deviate from some earlier published studies and why plant-soil feedback may not in all cases, or not in all comparisons, explain patterns of local dominance of introduced exotic plant species.
authors.affiliation: Plant Research International, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands Laboratory of Nematology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands tanjaspeek@gmail.com.
authors.forename: Tanja A A
authors.initials: TA
authors.lastname: Speek
authors.affiliation: Centre for Ecosystem Studies, Wageningen University and Research Centre, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands Department of Ecology, Aquatic Ecology and Environmental Biology Research Group, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Joop H J
authors.initials: JH
authors.lastname: Schaminée
authors.affiliation: Laboratory of Entomology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
authors.forename: Jeltje M
authors.initials: JM
authors.lastname: Stam
authors.affiliation: Plant Research International, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
authors.forename: Lambertus A P
authors.initials: LA
authors.lastname: Lotz
authors.affiliation: Centre for Ecosystem Studies, Wageningen University and Research Centre, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands.
authors.forename: Wim A
authors.initials: WA
authors.lastname: Ozinga
authors.affiliation: Laboratory of Nematology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands.
authors.forename: Wim H
authors.initials: WH
authors.lastname: van der Putten
keywords: Exotic species; introduced species; local dominance; macro ecology; residence time; soil-borne enemy