title: Historical Invasion Records Can Be Misleading: Genetic Evidence for Multiple Introductions of Invasive Raccoons (Procyon lotor) in Germany.
abstract: Biological invasions provide excellent study systems to understand evolutionary, genetic and ecological processes during range expansions. There is strong evidence for positive effects of high propagule pressure and the associated higher genetic diversity on invasion success, but some species have become invasive despite small founder numbers. The raccoon (Procyon lotor) is often considered as a typical example for such a successful invasion resulting from a small number of founders. The species' largest non-native population in Germany is commonly assumed to stem from a small number of founders and two separate founding events in the 1930s and 1940s. In the present study we analyzed 407 raccoons at 20 microsatellite loci sampled from the invasive range in Western Europe to test if these assumptions are correct. Contrary to the expectations, different genetic clustering methods detected evidence for at least four independent introduction events that gave rise to genetically differentiated subpopulations. Further smaller clusters were either artifacts or resulted from founder events at the range margin and recent release of captive individuals. We also found genetic evidence for on-going introductions of individuals. Furthermore a novel randomization process was used to determine the potential range of founder population size that would suffice to capture all the alleles present in a cluster. Our results falsify the assumption that this species has become widespread and abundant despite being genetically depauperate and show that historical records of species introductions may be misleading.
authors.affiliation: Department of Biogeography, Trier University, Trier, Germany.
authors.forename: Mari L
authors.initials: ML
authors.lastname: Fischer
authors.affiliation: Department of Biogeography, Trier University, Trier, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Hochkirch
authors.affiliation: Musée National d'Histoire Naturelle, Luxembourg, Luxembourg.
authors.forename: Mike
authors.initials: M
authors.lastname: Heddergott
authors.affiliation: Landeslabor Berlin-Brandenburg, Frankfurt (Oder), Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schulze
authors.affiliation: Lower Saxony State Office for Consumer Protection and Food Safety, Food and Veterinary Institute Braunschweig/Hannover, Hannover, Germany.
authors.forename: Helena E
authors.initials: HE
authors.lastname: Anheyer-Behmenburg
authors.affiliation: Institut für Tierökologie und Naturbildung, Gonterskirchen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Lang
authors.affiliation: Dresden University of Technology, Institute of Forest Botany and Forest Zoology, Tharandt, Germany.
authors.forename: Frank-Uwe
authors.initials: FU
authors.lastname: Michler
authors.affiliation: Department of Wildlife Ecology, Research Institute for Forest Ecology and Forestry Rhineland-Palatinate, Trippstadt, Germany.
authors.forename: Ulf
authors.initials: U
authors.lastname: Hohmann
authors.affiliation: Senckenberg Museum of Natural History Görlitz, Görlitz, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Ansorge
authors.affiliation: Thüringer Landesamt für Verbraucherschutz, Bad Langensalza, Germany.
authors.forename: Lothar
authors.initials: L
authors.lastname: Hoffmann
authors.affiliation: Department of Biogeography, Trier University, Trier, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Klein
authors.affiliation: Musée National d'Histoire Naturelle, Luxembourg, Luxembourg.
authors.forename: Alain C
authors.initials: AC
authors.lastname: Frantz
mesh_terms: D000818:Animals; D017753:Ecosystem; D018703:Founder Effect; D014644:Genetic Variation / Q000235:genetics*; D005828:Genetics, Population; D005858:Germany; D058865:Introduced Species; D018895:Microsatellite Repeats / Q000235:genetics*; D011821:Raccoons / Q000235:genetics*; D014481:United States