The role of hybridization for the invasion success of meadow knapweed Centaurea x moncktonii in North America

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Biological invasions are a major threat for biodiversity and ecosystem functioning and at the same time excellent study systems for fundamental ecological and evolutionary research questions. Choosing the optimal management strategies requires a mechanistic understanding of the ecological and evolutionary processes underlying invasion dynamics and success. The proposed project addresses inter-specific hybridization, genomic admixture and genome size variation as mechanisms that facilitate the evolution of traits that are indicative of invasiveness. The study system, the Centaurea x moncktonii (meadow knapweed) hybrid complex, comprises a set of parental species and their hybrids that are native in Eurasia and invasive in North America. Meadow knapweed is spreading rapidly in a majority of the United States and has severe negative ecological and economic impact. We will combine studies of genomic and quantitative trait variation to:1. Describe the genomic composition and degree of hybridization in highly invasive Northeastern North American populations;2. Link variation in genome size and quantitative traits to the genomic variation and taxonomic identity of individuals;3. Elucidate if individuals with a high degree of genomic admixture exhibit traits that are commonly associated with invasiveness; 4. Clarify if individuals with small genome size exhibit traits that are commonly associated with invasiveness.In summary, this project will yield a first description of the genomic composition and taxonomic identity of meadow knapweed populations in the Northeastern United States. It will clarify the relationships between genome size variation, taxonomic identity, genomic admixture and phenotypic traits indicative of invasiveness. The results will provide a foundation for further exploration of the genomic consequences of hybridization as well as the genomic basis of adaptive evolution of invasiveness in C. x moncktonii hybrid swarms. This information will help developing management strategies for Centaurea x moncktonii in North America.