Determinants of plant invasiveness in clonal speciesan experimental approach with Carpobrotus edulis (L.) N. E. Br. and Alternantera philoxeroides (Mart.) Griseb

Abstract

Biological invasions are one of the main causes of global biodiversity loss. The reason why only a few alien species become invasive has yet to be clarified. In this doctoral thesis, a series of experiments have been conducted to elucidate the role played by different traits associated with clonal reproduction in biological invasions. In chapters I and II, field experiments were carried out to investigate the benefit of physiological integration in Carpobrotus spp. Chapters III and IV delve into the selection of phenotypic plasticity and the competitive ability of Carpobrotus spp. throughout the processes of biological invasions. Chapter V focuses on the role of physiological integration in the defensive response to real and simulated herbivory by the invasive plant Alternanthera philoxeroides. Chapter VI evaluates the role of DNA methylation as an epigenetic transmission mechanism of phenotypic plasticity for this species. Finally, in chapter VII a dynamic simulation model for the biocontrol of A. philoxeroides is proposed, using the insect Agasicles hygrophila in a model population located in Fisterra, Galicia (NW Spain).