Multiple founder effects are followed by range expansion and admixture during the invasion process of the raccoon (Procyon lotor) in Europe

Abstract

Aim Understanding colonization dynamics is crucial for management of invasive species. We compare the genetic structure of historical (Central Europe) and recent (Spain) invasive populations with native and captive populations of the North American raccoon (Procyon lotor). Our aim was to analyse the effects of colonization age on genetic population structure, understand the role of captive individuals as potential founders and test the role of rivers for the dispersal of the species.Location North America, Spain, Central Europe.Methods We genotyped wild-caught raccoons from Spain and Central Europe (N = 596), zoos (N = 57) and the native range (N = 153) at 16 microsatellite loci and sequenced a mitochondrial DNA fragment (Control Region). We analysed population genetic structuring with Bayesian assignment methods and a FCA. In a landscape genetic analysis, we tested the effect of waterways in the dispersal of the species. ResultsWe detected 16 genetic clusters (in BAPS), supporting the hypothesis of multiple introductions and ongoing releases in the invasive range. The native population showed nearly no genetic structure, the Central European clusters showed signals of admixture, whereas the Spanish clusters were clearly separated. Admixture of the Central European clusters was probably caused by recent contact of populations with different origin. The landscape genetic analysis showed that rivers represent neither barriers nor corridors in Central Europe.Main conclusions As the Spanish populations are genetically more diverse than the Central European, we expect increased within-population diversity when the still isolated populations merge after range expansion. As our results provide evidence for gene flow between zoos and free-ranging populations, better control of pet trade is essential in the management efforts concerning this invasive species. Our study shows that genetic analyses can help to reconstruct invasion processes, which is important for better understanding and effective management of invasive species.

Is the raccoon (Procyon lotor) out of control in Europe?

“…In Europe, most raccoon populations have been founded by a few individuals Fischer et al , 2017. Despite low genetic diversity, as a result of the founder effect and population bottleneck, introduced raccoons have become invasive Fischer et al , 2017. Moreover, high propagule pressure (i.e.…”

Comparing raccoon major histocompatibility complex diversity in native and introduced ranges: Evidence for the importance of functional immune diversity for adaptation and survival in novel environments

“…Poland was already colonized from both directions: south (Czechia) and west (Germany) with the contact zone in the western central region (Biedrzycka et al, 2014). We should expect similar patterns in western Europe between raccoons introduced to Spain and Germany, as those populations also belong to different genetic clusters (Fischer et al, 2017).…”

“…Raccoons were successfully introduced in Germany, in the 1930s with a limited number of individuals (Jernelöv, 2017). Recent genetic analyses suggest that there were at least four small-scale, independent initial introduction events of raccoon (Fischer et al, 2017). Recently, approximately 1,000,000 raccoons were estimated to be living in Germany, and the range of the species in Europe has extended to the West, East and South of the invasion core (Bartoszewicz, Okarma, Zalewski, & Szczesna, 2008;Lutz, 1984).…”

Analysing the recolonisation of a highly fragmented landscape by wild boar using a landscape genetic approach

“…How a landscape is perceived by a certain species does not necessarily match human presumptions of landscape connectivity or habitat quality (Cushman et al 2006). Understanding the interaction between geographical/environmental features and genetic variation can reveal discontinuities in the landscape such as barriers, the extent of landscape connectivity (Balkenhol et al 2013, Parks et al 2015, Kierepa and Latch 2016, Norman et al 2016, Villemey et al 2016, Cox et al 2017, aid understanding of colonisation and expansion processes of invasive species (Fischer et al 2017) and delineate management units for species management (e.g. ungulates; Coulon et al 2006, Frantz et al 2009).…”

“…Knowledge about landscape elements that affect dispersal is essential for developing effective management strategies of fast expanding species (Scandura et al 2008, Nikolov et al 2009, Frantz et al 2010, Fischer et al 2017. One such fast expanding species is the wild boar Sus scrofa L. Since the 1960s wild boar populations have been expanding throughout Europe (Saez-Royuela and Telleria 1986, Acevedo et al 2007, Massei et al 2015) and much of their invasive distribution range (New Zealand: Bengsen et al 2018;Australia: Choquenot et al 1996;North America: Mayer 2018, McClure et al 2015South America: Salvador and Fernandez 2018).…”