Abstract Detail


Huebner, Cynthia [1], Corbett, Cameron [2], Ferrari, Lorenzo [3], Kosslow, Lauren [4], Skibicki, Sam [5], Barrett, Craig [6].

Traits that Define Invasiveness in Microstegium vimineum (Japanese stiltgrass) at Local and Regional Scales.

Phenotypic traits associated with plant invasiveness include those indicative of increased fitness (prolific seed production, high germination rates, greater seed mass) and increased competitive ability (rapid growth, greater biomass production). Further, trait plasticity or the ability to adapt rapidly are essential for stochastic environments and successful range expansion of invasive plants. We compared traits of the invasive annual grass Microstegium vimineum regionally across latitudes and longitudes and locally in different habitats. We hypothesized that fitness-related traits would vary regionally, but not locally. In contrast, traits associated with competition would vary across both regional and local scales. We collected both plants and seed from a total of 339 individuals and 48 populations in the grass’ nonnative US range encompassing 15 states. Collections at the local scale came from a dry habitat (southwest-facing slope) and a wet habitat (riparian area). Growth measures were taken from field specimens (parent plants) as well as from F1 generation plants grown from selfed-parent plant seed under greenhouse conditions (Morgantown, WV). Our fitness variables included floret mass from both parent and F1 plants, days to flower and seed maturation from F1 plants, and germination percentages of seed from both parent and F1 plants. Our competition variables included plant height, average internode length, number of branches, and shoot biomass from parent and F1 plants. We evaluated each measured trait against latitude and longitude using simple regression and between habitat types using generalized linear models and Kruskal-Wallis nonparametric tests. Both parent and F1 plants from higher latitudes and more easterly longitudes flowered earlier, had later seed maturation, lower germination percentages, and no significant difference in floret weight; these same traits did not differ significantly in terms of mesic vs xeric habitats, except for riparian area plants taking longer to flower. The four competition variables differed significantly between the two habitats for the parent plants but not the F1 plants with the riparian plants being taller, having greater biomass, larger average internodes, and more branches than the dry-slope plants. There was also a trend for plant height, number of branches, and biomass to decrease with increasing latitude for F1 plants but to increase with increasing latitude for the parent plants. Average internode length increased with increasing latitude for F1 plants and was not significant for the parent plants. These contrasting responses between the parent and F1 plants support our hypothesis that fitness-related traits are associated with longer-term climatic factors, whereas competitive traits are associated with shorter-term local-scale factors, such as moisture. The fitness traits are, thus, most likely genetically determined while the competition traits are plastic. In the event climate change results in a shift of warmer conditions to more northern latitudes, our data may predict greater germination percentages of M. vimineum along with later flowering but earlier seed set. However, decreasing local moisture conditions may reduce plant productivity of this species. Our data also reveal at least two morphological characteristics that appear to be linked with the fitness traits, including leaf length-to-width ratio and presence or absence of awns.

1 - 1514 Westbrook Dr, Morgantown, WV, 26508, United States
2 - 53 Campus Drive, Morgantown, WV, 26505, United States
3 - 180 Canfield St, Morgantown, WV, 26505, USA
4 - West Virginia University, Biology, Morgantown, WV, 26501, USA
5 - 1303 College Ave, Morgantown, WV, 26505, United States
6 - West Virginia University, Biology, 53 Campus Drive, Morgantown, WV, 26506, United States

Plant invasion
plant traits
Range expansion
Phenotypic plasticity.

Presentation Type: Oral Paper
Number: EC09006
Abstract ID:231
Candidate for Awards:None

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