title: Loss of genetic diversity and increased embryonic mortality in non-native lizard populations.
abstract: Many populations are small and isolated with limited genetic variation and high risk of mating with close relatives. Inbreeding depression is suspected to contribute to extinction of wild populations, but the historical and demographic factors that contribute to reduced population viability are often difficult to tease apart. Replicated introduction events in non-native species can offer insights into this problem because they allow us to study how genetic variation and inbreeding depression are affected by demographic events (e.g. bottlenecks), genetic admixture and the extent and duration of isolation. Using detailed knowledge about the introduction history of 21 non-native populations of the wall lizard Podarcis muralis in England, we show greater loss of genetic diversity (estimated from microsatellite loci) in older populations and in populations from native regions of high diversity. Loss of genetic diversity was accompanied by higher embryonic mortality in non-native populations, suggesting that introduced populations are sufficiently inbred to jeopardize long-term viability. However, there was no statistical correlation between population-level genetic diversity and average embryonic mortality. Similarly, at the individual level, there was no correlation between female heterozygosity and clutch size, infertility or hatching success, or between embryo heterozygosity and mortality. We discuss these results in the context of human-mediated introductions and how the history of introductions can play a fundamental role in influencing individual and population fitness in non-native species.
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Rd, OX1 3PS, Oxford, UK.
authors.forename: Sozos N
authors.initials: SN
authors.lastname: Michaelides
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Rd, OX1 3PS, Oxford, UK.|School of Biological Sciences, University of Tasmania, PO Box 55, Hobart, Tas., 7001, Australia.
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: While
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Rd, OX1 3PS, Oxford, UK.
authors.forename: Natalia
authors.initials: N
authors.lastname: Zajac
authors.affiliation: Station d'Ecologie Expérimentale du CNRS à Moulis, 09200, Moulis, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Aubret
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA.
authors.forename: Brittny
authors.initials: B
authors.lastname: Calsbeek
authors.affiliation: Dipartimento Sci Terra & Ambiente, Lab Ecoetol, Università di Pavia, I-27100, Pavia, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sacchi
authors.affiliation: Museo di Storia Naturale, Università di Pisa, Via Roma, 79, 56011, Calci, Pisa, Italy.
authors.forename: Marco A L
authors.initials: MA
authors.lastname: Zuffi
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, South Parks Rd, OX1 3PS, Oxford, UK.|Department of Biology, Lund University, Sölvegatan 37, SE 223 62, Lund, Sweden.
authors.forename: Tobias
authors.initials: T
authors.lastname: Uller
mesh_terms: D000818:Animals; D004739:England; D005260:Female; D056084:Genetic Fitness; D014644:Genetic Variation; D005828:Genetics, Population; D058865:Introduced Species; D008116:Lizards / Q000196:embryology / Q000235:genetics*; D018895:Microsatellite Repeats
keywords: colonization; genetic diversity; hatching failure; inbreeding; lizard