Biological invasions: a temporal, spatial and plastic point of view: the case of Discoglossus pictus in Europe = Invasions biològiques: un punt de vista temporal, espaial i plàstic : el cas de Discoglossus pictus a Europa
The rates at which allochthonous species are introduced and become invasive worldwide are unprecedented and accordingly, the number of studies on invasion biology have increased during the past years. However, biological invasions are still seemingly underused as natural laboratories to test essenti...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/456898 |
| Acceso en línea: | http://hdl.handle.net/10803/456898 |
| Access Level: | acceso abierto |
| Palabra clave: | Invasions biològiques Invasiones biológicas Biological invasions Granotes Ranas Frogs Europa Europe Ciències Experimentals i Matemàtiques 574 |
| Sumario: | The rates at which allochthonous species are introduced and become invasive worldwide are unprecedented and accordingly, the number of studies on invasion biology have increased during the past years. However, biological invasions are still seemingly underused as natural laboratories to test essential biological theory. In this sense, the nine studies – ordered in three parts, which function as thematic blocks – presented in this thesis try to globally give an evolutionary – apart from ecologic – point of view on the ongoing invasion of the Mediterranean Painted Frog (Discoglossus pictus) in Europe. This frog is native to Northern Africa and was introduced from Algeria in Southern France approximately a century ago, being nowadays present on a wide coastal strip of approximately 250km in SE France and NE Spain, constantly colonizing new areas. The aim of “PART A: Intraspecific variation along the invasive range of Discoglossus pictus” is the examination at a phenotypic and genomic level of possible differences across populations within the invasive range of the species. We observe that the Mediterranean Painted Frog is not a uniform unit in its invasive range in Europe: mean size of adults and life-history traits related to mean annual precipitation, while substantial genetic differences among populations are most probably created by the expansion history itself. The aim of “PART B: Intraguild competition in tadpoles of Discoglossus pictus” is to study and discuss the role of Discoglossus pictus tadpoles as potential competitors for the larvae of native anurans. We here see that the Mediterranean Painted Frog represents, physiologically, a unique addition to the local tadpole guild, characterized by a very rapid and consumption-oriented growth, and that these tadpoles are able to increase the quality and quantity of its food intake when these possibilities are provided. This poses these tadpoles as potentially very disruptive of the natural dynamics of native anurans. Concerning the competitive relationship between the Natterjack Toad (Epidalea calamita) and the Mediterranean Painted Frog, we can observe that it changes according to previous evolutionary history of populations. In this sense, populations of the native toad that have had a greater number of generations of contact with the invasive frog are able to inflict a greater competitive distress on the invasive tadpoles. Both competitors also differ mildly in their breeding preferences, but nevertheless, both species seem forced to end up competing very often at a pond level. Within ponds, the trophic position of both species can respond either to evolutionary or to ecological patterns with the data gathered hitherto. Finally, in “PART C: Tadpoles of Discoglossus pictus as prey for aquatic native predators”, two studies examine if invasive tadpoles modify its phenotypes in front of an array of – native and invasive – predators, testing also the effectiveness of the possible changes. Interestingly, the invasive frog presents a pattern of inducible defences which would be expected for a native anuran, responding to all native predators effectively, while lacking responses in front of introduced or invasive predators. Globally, the complex evolutionary history of the local anuran assemblages poses the Mediterranean Painted Frog as a good model for ecological and evolutionary studies reaching beyond invasion biology, as it is very particular case of invasive species, in which effects of previous recurrent shared evolutionary history with similar competitor / predator species are probably present. |
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