Biological invasions by alien species pose major threats to biodiversity, but also act as a natural experiment providing many insights about ecological and evolutionary processes. Although conservation managers usually have to deal with multiple invasive species that co-occur in native ecosystems, research to date has concentrated on the study of single highly invasive species. Consequently, this project aims to better understand the interactions among multiple co-occurring alien plants, particularly investigating when such interactions may be competitive or facilitative. Moreover, in order to generalise results beyond the study system, the project aims to determine how mechanisms of competition or facilitation relate to patterns of phylogenetic relatedness and similarity in functional traits. To this end, common garden experiments are carried out that investigate interactions among 24 alien annual plant species from six plant families. In a first experiment, the pairwise interactions between all possible combinations of species are studied. Thereafter a second experiment will investigate the interactions in a native plant community situation with varying numbers and density of alien species. By following plant performance over two years population growth can be measured. Establishment, growth and reproduction of the alien species will then be related to their evolutionary history and functional traits. Finally, local performance of the invaders is related to large-scale success, that is, invasive spread. The resulting better understanding on the extent of facilitative or competitive interactions among multiple plant invaders is crucial to determine appropriate control measures that ensure the conservation of native species. Moreover, the project will contribute to ecological theory of community assembly in general.
Project start 01/03/2018
Project end 31/12/2022
Sponsor mark (sponsor) Baden-Württemberg Stiftung, Eliteprogramme for Postdocs
