Altitudinal variation in Microstegium vimineum, an invasive plant species

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Alexandra M. Congelosi (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Elizabeth Lacey

Abstract: Invasive plant species are becoming a major concern because they have been found to have negative effects such as decreasing biodiversity and inhibiting growth of native species. Microstegium vimineum, also known as Japanese stiltgrass, is such an invasive species. Because M. vimineum has spread quickly to many variable environments in the United States and because it is also an annual plant species, it is possible that this invasive grass has undergone contemporary evolution. I hypothesized that M. vimineum is undergoing contemporary evolution via local adaptation. With growth chamber and field experiments, I specifically tested the hypothesis that highaltitude populations have adapted to their cool environments by having higher germination, seed number, and reproductive effort at cool temperatures, and that the opposite is true for low-altitude populations. I also tested two hypotheses regarding the selective advantage of cleistogamy, the resource allocation hypothesis and the optimal genotype hypothesis. To test the hypothesis, I measured germination, flower phenology, total seed number, chasmogamous and cleistogamous seed number, percent cleistogamous/total seed number, and reproductive effort of plants from populations sampled along an altitudinal gradient. Plants were grown outside and in two growth chambers set at two temperatures. For the growth chamber experiment, I found that altitude affected germination, total seed number, and percent cleistogamous seeds. Temperature also affected germination, total seeds, cleistogamous seed number, and percent cleistogamous seeds. Low-altitude populations had higher germination and seed number in warm temperatures and high-altitude populations had higher germination and seed number in cool temperatures. There was an altitude by temperature interaction for total seeds, number cleistogamous seeds, and percent cleistogamous seeds. For the field experiment, altitude had an effect on germination, number of chasmogamous seeds, and reproductive effort per plant. As altitude increased, germination and number of chasmogamous seeds decreased, and reproductive effort increased. My results are consistent with the hypotheses that M. vimineum shows phenotypic variation associated with altitude and temperature and has undergone contemporary evolution in North Carolina.

Additional Information

Language: English
Date: 2013
Invasive plant species, Microstegium vimineum, Japanese stiltgrass,
Invasive plants $x Effect of temperature on
Invasive plants $x Adaptation
Grasses $x Effect of temperature on
Grasses $x Adaptation

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