Understanding plant invasions: a global scale meta-analysis

PhD ceremony: Mr. A. Ordoñez Gloria, 16.15 uur, Aula Academiegebouw, Broerstraat 5, Groningen

Dissertation: Understanding plant invasions: a global scale meta-analysis

Promotor(s): prof. H. Olff

Faculty: Mathematics and Natural Sciences

The globalization of human activities has resulted in the intentional and un-intentional movement of species to areas beyond their natural range; ultimately causing biotic homogenization and irreversible changes to ecosystems. The dissertation of Alejandro Ordoñez Gloria addresses the invasiveness and invasibility question by exploring global patters of trait similarity between co-occurring alien and native plants. To do this, two questions were asked: Can trait similarity between aliens and natives explain aliens success? And are the observed similarity patterns a product of evolution?

Aliens were found to display higher leaf traits, lower canopy height and smaller seeds. The magnitude of trait differences between co-occurring aliens and natives remained the same along climatic edaphic and human disturbance gradients. These differences showed a strong dependence to the phylogenetic relation between aliens and the native community; with phylogenetically close co-occurring alien and native plants being more phenotypically similar than expected by chance. These differences in traits were the result of aliens conserving their traits once introduced to a new area; something we suggest emerges from core ecological, evolutionary physiological and genetic constraints. The work of Ordoñez Gloria is a contribution to the long lasting quest for understanding the causes and mechanisms behind the success of invasive species. Lastly, it is shown how species, community and evolutionary patterns must be accounted together to determine invasion risk.