View Program - 2022 Population, Evolutionary, and Quantitative Genetics Conference

The global spread of invasive species is a major source of ecological and financial concern, but what determines where invaders end up establishing? We address this question by examining the role of genetic variation on the invasion success of common ragweed Ambrosia artemisiifolia. Ragweed is a globally invasive species known for releasing highly allergenic pollen. Native to North America, it was first introduced to Europe before invading Australia's east coast in the 1930s. The Australian distribution of this species is conspicuously narrow compared to North America and Europe, prompting an investigation into the factors driving this discrepancy. Genomic data was used to identify ancestral genomic clusters and build genetically-informed ecological niche models to characterize intraspecific niche differentiation. Genetic clusters showed significant differences in habitat preference with respect to temperature and precipitation, indicating a strong association between genomic and environmental variation. Projecting the habitat preferences of native North American and old invasive European clusters to Australia showed the potential distribution of ragweed on the continent is greater than currently observed, but only when European plants are introduced to the country. North American plants had a surprisingly narrow potential distribution, suggesting it was less adapted to Australian conditions than plants from Europe. These findings highlight the role of genomic variation in successful invasions, and suggest adaptive evolution in previous invasive ranges can produce populations with greater invasive potential than those from the native range.

Second time's the charm: adaptive evolution following a prior invasion increases the potential distribution of an invasive weed