Résumé
Adaptation is essential for non-native species to establish and spread in a new range. This can include pre-adaptation, when a new population is founded by a source that has evolved to thrive under those same conditions, and post-introduction adaptation, when rapid adaptive changes occur after introduction. Research into these processes in introduced species is still relatively rare, especially in marine systems, despite the extraordinary evolutionary diversity of marine life. Genomic tools are improving our ability to understand the nature of the adaptive changes occurring in introduced populations and the conditions under which they arise. Based on theoretical considerations and empirical studies, this chapter shows that selection on standing genetic variation and admixture processes (including hybridization) are pivotal mechanisms by which non-native species can genetically adapt to new environments, illustrated here with marine case studies.