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Fischer M.L.,University of Trier | Hochkirch A.,University of Trier | Heddergott M.,Musee National DHistoire Naturelle | Schulze C.,Landeslabor Berlin Brandenburg | And 8 more authors.
PLoS ONE | Year: 2015

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. © 2015 Fischer et al. Source


Background: Since 2009, all newborns in Germany have been entitled to universal neonatal hearing screening (UNHS). UNHS with tracking of test results leads to earlier detection of hearing disorders. The Association of German Hearing Screening Centers (Verband Deutscher Hörscreening-Zentralen, VDHZ) was founded to promote nationwide tracking, validity and quality control of UNHS results. Objectives: A comparable data structure in the different screening centers, with uniform definitions of primary parameters is essential for the nationwide evaluation of UNHS results. To address the question of whether a data structure with comparable definitions already exists or still has to be created, the existing structures and primary parameter definitions in the hearing screening centers should be investigated and compared. Methods: A survey was conducted in all hearing screening centers to assess how data on the primary UNHS parameters defined in pediatric guidelines was gathered. In the case of discrepancies, uniform definitions were created. Finally, the practicability of these definitions was evaluated. Results: Due to differing definitions of primary parameters, some of the data were not comparable between the individual centers. Therefore, uniform definitions were created in a consensus process. In the centers, the screening method, the two-step first screening and the result of the first screening now correspond to these uniform definitions. Other parameters, e.g. the total number of newborns, still vary widely, rendering the comparison of screening rates almost impossible. Conclusion: Valid evaluation of UNHS not only requires nationwide establishment of hearing screening centers, but also unified data structures and parameter definitions. © 2014 Springer-Verlag Berlin Heidelberg. Source

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