MUSEUM NATIONAL D’HISTOIRE NATURELLE Ecole Doctorale Sciences de la Nature et de l’Homme – ED 227 Année 2017 N°attribué par la bibliothèque |_|_|_|_|_|_|_|_|_|_|_|_| THESE Pour obtenir le grade de DOCTEUR DU MUSEUM NATIONAL D’HISTOIRE NATURELLE Spécialité : Ecologie Présentée et soutenue publiquement par Julien Courant Le 19 Septembre 2017 Invasive biology of Xenopus laevis in Europe: ecological effects and physiological adaptations Sous la direction de : Monsieur Herrel, Anthony, Directeur de Recherche, Et Monsieur Secondi Jean, Maître de conférences JURY : M. Clergeau, Philippe Professeur, Muséum national d’histoire naturelle, Paris (075) Président M. Herrel, Anthony Directeur de Recherche, Muséum national d’histoire naturelle, Paris (075) Directeur de Thèse M. Secondi, Jean Maître de conférences, Université de Lyon, Lyon (069) Directeur de Thèse M. Besnard, Aurélien Maître de conférences, CEFE-CNRS, Montpellier (034) Rapporteur M. Rödel, Mark-Oliver Professeur, Museum für Naturkunde, Berlin (Germany) Rapporteur M. Measey, John Chargé de Recherche, Stellenbosch University, Stellenbosch (South Africa) Examinateur M. Miaud, Claude Directeur de Recherche, Centre National de la Recherche Scientifique, Paris (075) Examinateur i iii Table of contents Résumé ....................................................................................................................................... 2 General Introduction ................................................................................................................. 6 Chapter I - Are invasive populations characterized by a broader diet than native populations? .................................................................................................................................................. 20 Introduction ...................................................................................................................... 24 Material and Methods ...................................................................................................... 27 Results ............................................................................................................................... 30 Discussion ......................................................................................................................... 37 Chapter II - Assessing the impact of an invasive population of the African clawed frog on an amphibian community in western France. .................................................................................................................................................. 42 Introduction ...................................................................................................................... 46 Material and Methods ...................................................................................................... 48 Results ............................................................................................................................... 54 Discussion ....................................................................................................................... 587 Second Part - Introduction ....................................................................................................... 64 Chapter III - Resources allocated to reproduction decrease at the range edge of an expanding population of an invasive amphibian. .................................................................................................................................................. 70 Introduction ...................................................................................................................... 74 Material and Methods ...................................................................................................... 76 Results ............................................................................................................................... 83 v Discussion ......................................................................................................................... 87 Chapter IV - Differences in mobility at the range edge of an expanding invasive population of Xenopus laevis in the west of France. .................................................................................................................................................. 92 Introduction ...................................................................................................................... 96 Material and Methods ...................................................................................................... 98 Results ............................................................................................................................. 105 Discussion ....................................................................................................................... 110 Chapter V - Changes in dispersal allocation at the range edge of an expanding population. ................................................................................................................................................ 114 Introduction .................................................................................................................... 118 Material and Methods .................................................................................................... 121 Results ............................................................................................................................. 128 Discussion ....................................................................................................................... 133 Chapter VI - Dynamic demography and time since colonization in an expanding population. ................................................................................................................................................ 138 Introduction .................................................................................................................... 142 Material and Methods .................................................................................................... 146 Results ............................................................................................................................. 151 Discussion ....................................................................................................................... 156 General Discussion ................................................................................................................. 162 References .............................................................................................................................. 176 Appendices ............................................................................................................................ 210 Abstract .................................................................................................................................. 307 vii Figures list Fig.Int.1 Photographical description of Xenopus laevis. .................................................................................................................................................. 13 Fig.Int.2 Global projection of the potential distribution of X. laevis. .................................................................................................................................................. 15 Fig.Int.3 General principle of the sampling design used during the studies performed on the invasive population of Xenopus laevis in western France. .................................................................................................................................................. 17 Fig.1.1 Two first principal components of the PCA representing the populations according to their diet. .................................................................................................................................................. 31 Fig.1.2 Occurrence of the main ecological traits among the five populations: terrestrial prey (black), benthic prey (dark blue), nektonic items (sky blue) and planktonic prey (cyan). .................................................................................................................................................. 34 Fig.1.3 Niche breadth calculated for diet data in native and colonized ranges of Xenopus laevis. .................................................................................................................................................. 35 Fig.1.4 Electivity index for each aquatic prey category consumed in South Africa (brown), Wales (dark-orange) and France (light-orange). .................................................................................................................................................. 36 Fig.2.1 Distribution of the expanding population of Xenopus laevis in western France, with the sites (in yellow) selected for the site-occupancy study. .................................................................................................................................................. 49 Fig.2.2 N-mixture estimates of species richness according to (a) the abundance of Xenopus laevis and (b) the distance to the introduction site. ix .................................................................................................................................................. 56 Fig.3.1 Location of the three pond clusters of Xenopus laevis sampled to analyze the variation in resource allocation