Presented at Evolution 2016

Research area: evolutionary_biology

Landscape connectivity of a noxious invasive weed: human-aided or natural dispersal?

Created on 18th May 2016

Diego F Alvarado-Serrano; Megan Van Etten; Shu-Mei Chang; Regina Baucom;

Examining how the landscape may influence gene flow is at the forefront of understanding population differentiation and adaptation. Such understanding is crucial in light of ongoing environmental changes and the elevated risk of ecosystems alteration. In particular, knowledge of how humans may influence the structure of populations is imperative to elucidate their role in shaping the evolution of other species, and specifically how humans may alter the balance between genetic drift and selection. Here we characterize the population genetic structure of Ipomoea purpurea, a noxious invasive weed, and assess the relative roles of natural and human-driven landscapes on genetic differentiation. By combining rigorous statistical analyses and a combination of different molecular markers, we detect both common and marker-specific patterns of genetic connectivity and identify human-aided migration as an important component shaping the evolutionary history of this species. In particular, we identified human population density as an important predictor of pairwise population differentiation, suggesting that the agricultural and/or horticultural trade may be involved in maintaining some level of connectivity across agricultural fields. Climatic variation, primarily temperature, appears as an additional predictor when considering agricultural fields in the northern United States. We discuss the implications of these results and the approach we followed in the context of understanding agricultural weed and invasive species′ expansions, as well as the challenges and promises of current landscape genetics research.

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