Análisis multi-escalar de la capacidad invasora de Discoglossus pictus auritus (Amphibia, anura)

Resumen

Invasive Alien Species follow three phases: introduction, establishment and expansion. Few of the introduced species, reach the expansion phase successfully. Many traits are associated to invasiveness of a species and explain their invasion success. These traits vary between species and spatial scales. Despite being one of the most threatened groups, few studies have examined the factors that favour the invasion of amphibian species and its potential impact on native communities. The objective of this thesis was the analysis of the invasiveness of the painted frog (Discoglossus pictus auritus) at macro-, meso- and micro-scale. The species was introduced at final of XIX century in Banyuls sur Mer (France) and currently is expanding both in France and in Spain with abundant populations. Previous studies indicate its potential negative effect on the native community and the importance of increase the knowledge about the painted frog as an invasive species. While macro-scale provide useful predictive information of invasion success, meso-scale defines how species insert in new communities organization and micro-scale which particular traits favor its success. Our results at macro-scale showed that D. pictus introduction accomplished niche conservatism during its introduction. The existence of numerous suitable areas to colonize and the good dispersal abilities to expand throughout more unsuitable areas, predicts a range expansion in the future, mostly to the north because of climatic change. In the invaded area the species occupies mainly ephemeral ponds where presumably would obtain high reproductive success. D. pictus present good abilities to overcome desiccation events, but its plasticity is restricted to resources availability. It also displays phenotypic plasticity facing new predators but milder than the observed in native species. This reduced response could limit reproductive success of D. pictus in ponds with larger duration where predation and competition pressure increase. By last, the painted frog showed good trophic traits that are favourable for invasion of ephemeral ponds and could limit the fitness of a native species (B. calamita) when resources are scarced or there is a risk of pond desiccation. The integrative view derived of the three scales study let us to a better understanding of species invasion.