title: Are invaders different? A conceptual framework of comparative approaches for assessing determinants of invasiveness.
abstract: What determines invasiveness of alien organisms is among the most interesting and urgent questions in ecology. In attempts to answer this question, researchers compare invasive alien species either to native species or to non-invasive alien species, and this is done in either the introduced or native ranges. However, inferences that can be drawn from these comparisons differ considerably, and failure to recognize this could hamper the search for determinants of invasiveness. To increase awareness about this issue, we present a framework of the various comparisons that can be used to test for determinants of invasiveness, and the specific questions each comparison can address. Moreover, we discuss how different comparisons complement each other, and therefore should be used in concert. For progress in invasion biology, it is crucial to realize that different comparisons address different biological questions and that some questions can only be answered unambiguously by combining them.
authors.affiliation: Institute of Plant Sciences and Oeschger Centre, University of Bern, Altenbergrain 21, CH-3006 Bern, Switzerland. vkleunen@ips.unibe.ch
authors.forename: Mark
authors.initials: M
authors.lastname: van Kleunen
authors.forename: Wayne
authors.initials: W
authors.lastname: Dawson
authors.forename: Daniel
authors.initials: D
authors.lastname: Schlaepfer
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Jeschke
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
mesh_terms: D004463:Ecology / Q000379:methods; D017753:Ecosystem; D011157:Population Dynamics; D013045:Species Specificity