Widespread primary, but geographically restricted secondary, human introductions of wall lizards, Podarcis muralis

Abstract

Establishing the introduction pathways of alien species is a fundamental task in invasion biology. The common wall lizard, Podarcis muralis, has been widely introduced outside of its native range in both Europe and North America, primarily through escaped pets or deliberate release of animals from captive or wild populations. Here, we use Bayesian clustering, approximate Bayesian computation (ABC) methods and network analyses to reconstruct the origin and colonization history of 23 non-native populations of wall lizards in England. Our analyses show that established populations in southern England originate from at least nine separate sources of animals from native populations in France and Italy. Secondary introductions from previously established non-native populations were supported for eleven (47%) populations. In contrast to the primary introductions, secondary introductions were highly restricted geographically and appear to have occurred within a limited time frame rather than being increasingly common. Together, these data suggest that extant wall lizard populations in England are the result of isolated accidental and deliberate releases of imported animals since the 1970s, with only local translocation of animals from established non-native populations. Given that populations introduced as recently as 25 years ago show evidence of having adapted to cool climate, discouraging further translocations may be important to prevent more extensive establishment on the south coast of England.

Developmental plasticity in reptiles: Insights from temperature‐dependent gene expression in wall lizard embryos

“…We selected four populations from the species’ native distribution, two from France and two from central Italy. These two regions are inhabited by lizards belonging to two of the main genetic lineages of this species, which diverged about 2.5 million years ago (Gassert et al., ; Michaelides, While, Zajac, & Uller, ). In April 2015, we collected 13 gravid females from Western France (around Pouzagues [46.788 N, –0.837 E] altitude: 258 m; will be referred to as Fr1), 15 from the French Pyrenees ([42.860 N, 1.105 E]; altitude: 1396 m; Fr2), 18 from lowland Tuscany (Greve in Chianti [43.588 N, 11.318 E], Colle di Val d'Elsa [43.428 N, 11.118 E], Certaldo [43.548 N, 11.042 E]; altitude: 83–245 m; It1), and 15 from the Tuscan Apennines (around Saltino [43.727 N, 11.538 E]; altitude: 966 m; It2).…”

Signatures of selection in embryonic transcriptomes of lizards adapting in parallel to cool climate

“…There are currently more than 25 populations across southern England, and the introduction histories have been reconstructed in detail (Michaelides et al. ).…”

“…The nonnative Italian and French populations were introduced in the 1930s and 1980s for the Italian and French lineages, respectively (Michaelides et al. ). The native populations were chosen because they fall within the approximate geographic origin of the nonnative populations (Michaelides et al.…”

“…The native populations were chosen because they fall within the approximate geographic origin of the nonnative populations (Michaelides et al. ). Once in the laboratory, females were housed individually in cages (590 × 390 × 415 mm) with sand as substrate, bricks as shelter, and a water bowl.…”

“…F ST values were recalculated from a previously published dataset of 13 microsatellite loci (Michaelides et al. ) using Arlequin 3.5.1.3 (Excoffier and Lischer ). M ST values were calculated from the expected mean squares of a one‐way ANOVA with “introduction” as response variable (see File S2 for details).…”