TY - THES T1 - Origin, climate niche, population genetics and intraspecific hybridization of introduced wall lizard populations in Central Europe A1 - Schulte,Ulrich Y1 - 2012/08/14 N2 - Increasing human population, mobility and commerce all cause increases in the transport of biota. A fraction of these non-native species establish, spread and threaten native biodiversity (“invasive species”). The Common wall lizard (Podarcis muralis), a species with a sub-Mediterranean native distribution, has established more than 150 non-native populations in Central Europe. This species represents an ideal model system to examine the role of the source region on establishment success, to assess the genetic consequences of biological invasions and to study the consequences of intraspecific hybridisation on native lineages. In this thesis, 77 introduced populations in Central Europe have been assigned to eight geographically distinct evolutionary lineages using sequencing of mitochondrial DNA (Chapter I). In combination with species distribution models this dataset was used to test for intraspecific niche divergence in this invasive species. Although inter-lineage niche differentiation was strong, I found only a weak correlation between geographic origin and occurrence in the non-native range. Lineages with narrow realised niches still became successful invaders far outside their native range, most probably due to broader fundamental niches. For the population-genetic part of this study buccal swabs turned out to be a simple and efficient non-invasive sampling method for DNA analysis in lacertid lizards, being suitable as an alternative to tail-clipping (Chapter II). Using DNA-sequencing, I was also able to assign the northernmost introduced population of the Italian wall lizard, Podarcis siculus, to a region between the Po plain and the northern Adriatic region (Chapter III). Furthermore, I discovered an introduced population of Podarcis liolepis for the first time in Germany, which occurs in syntopy with a non-native P. muralis population (Chapter IV). Both are likely to originate from the eastern Pyrenees. Microsatellite analyses revealed no evidence for gene flow between the two species. Compared to native populations in Southern France, the introduced populations of both species retained high levels of genetic diversity, suggesting that propagule pressure was high. Along the Upper Rhine Rift, native wall lizard populations have come into contact with introduced Italian lineages. In these populations, rapid genetic assimilation caused by hybridisation with non-native wall lizards was found (Chapter V). The genetic diversity of such hybrid populations was substantially higher than in pure introduced and pure native populations. The relationship between genetic diversity and admixture level was non-linear and rapidly reached a maximum at an admixture level of two lineages. The strong extent of introgression in mixed populations and the rapid creation of hybrid swarms indicate that introductions of non-native lizards represent a serious threat to the genetic integrity of native populations. The fine scale genetic analysis of an expanding introduced wall lizard population in Passau (Chapter VI) demonstrated that significant genetic population structure can emerge rapidly at a small spatial scale. Genetic differentiation increased from the centre of introduction to the expanding range margin, while the genetic diversity decreased. In the final Chapter VII the most important findings are summarised, and the difficulties of phenotypic assignment of populations to evolutionary lineages are addressed. I also discuss the problem, how to deal with invasive populations in the light of the current conservation legislation. KW - Populationsgenetik KW - Invasion KW - Genetische Variabilität KW - Neozoen CY - Trier PB - Universitätsbibliothek Trier AD - Universitätsring 15, 54296 Trier L2 - http://ubt.opus.hbz-nrw.de/volltexte/2012/771 ER -