Novy, Ari , Flory, Luke , Hartman, Jean Marie .
Rapid evolution of phenology during invasion of the grass Microstegium vimineum in North America.
Microstegium vimineum (Poaceae, tribe Andropogoneae) is a C4, shade tolerant, short-day flowering, annual grass considered to be among the most invasive plants in the eastern United States. It forms dense monocultures in forests, fields and disturbed areas where it can suppress native species and disrupt ecosystem function. M. vimineum was first recorded in North America in Knoxville, TN in 1919, though it may have been introduced elsewhere. By 1972 its range extended from Florida to New Jersey, and west to Ohio and Mississippi. It is currently found as far north as Massachusetts, as far west as Texas and Missouri, and as far south as Puerto Rico. To examine evolution of invasive M. vimineum phenology, and to evaluate the potential impact of this evolution on range expansion, we collected 10 populations of M. vimineum from throughout its invasive range. Populations were grown in controlled environment growth chambers under two distinct light regimes: one simulating daylength conditions near the northern limit of the invasive range and one simulating conditions near the southern limit. We found that the average critical flowering day length for each population was significantly predicted by latitudinal origin under both treatments (R2=0.89, p<0.001 and R2=0.85,p<0.001 for northern and southern treatments respectively). Since herbarium records indicate that M. vimineum was introduced in the southeastern United States and then radiated outward, we conclude that the variation in phenologic phenotypes recorded from populations outside the original introduction area must have arisen by evolution during the last 100 years. Our results indicate that rapid evolution in M. vimineum phenology may have contributed to range expansion in this invasive grass.
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1 - Rutgers University, Departments of Plant Biology and Landscape Architecture, 59 Dudley Rd., New Brunswick, NJ, 08901, USA
2 - Indiana University, Department of Biology, 1001 East 3rd Street, Bloomington, IN, 47405, USA
3 - Rutgers University, Department of Landscape Architecture, 93 Lipman Drive, New brunswick, NJ, 08901, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell C/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 8:00 AM