Abstract
Cities and adjacent regions represent foci of intense human activity and provide unique opportunities for studying human-mediated dispersal and gene flow. We examined the effect of landscape features on gene flow in the invasive grass
Brachypodium sylvaticum
across an urban–rural interface at the edge of its expanding range. We used genome-wide single-nucleotide polymorphism surveys of individuals from 22 locations. Resistance surfaces were created for each landscape feature, using ResistanceGA to optimize resistance parameters. Our S
tructure
analysis identified three distinct clusters, and diversity analyses support the existence of at least three local introductions. Multiple regression on distance matrices showed no evidence that development, roads, canopy cover or agriculture had a significant influence on genetic distance in
B. sylvaticum
. Geographical distance was a mediocre predictor of genetic distance and reflected geographical clustering. The model of rivers acting as a conduit explained a large portion of variation in genetic distance, but the lack of evidence of directional gene flow eliminated hydrochory as a dispersal mechanism. These results and observations of the distribution of populations in disturbed sites indicate that the influence of rivers on patterns of dispersal of
B. sylvaticum
probably reflects seed dispersal due to human recreational activity.
Subject
General Agricultural and Biological Sciences,General Environmental Science,General Immunology and Microbiology,General Biochemistry, Genetics and Molecular Biology,General Medicine
Cited by
21 articles.
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