Invasion: Japanese Stilt-grass


Here in southern Appalachia, we have an interesting invasive plant invader that Coweeta LTER Scientists have been studying. Japanese Stilt- grass — also known as Nepalese Browntop or porcelain packing grass — (Micorstegium vimineum) is a shade-tolerant annual grass in our forests that we think deserves more attention given some of the changes it is causing within local ecosystems.

Stilt-grass grows throughout the summer in a variety of forest conditions. The leaves are pale green and lance shaped and can be from one to three inches long. Stilt-grass leaves have a distinctive silvery mid vein that helps distinguish it from some native grasses, and it has short, stilt-like roots for which it derives its common name. Stilt-grass is successful in part because it is a very flexible plant. It can survive and reproduce in widely varying conditions, from dry, open areas to moist, stream-side areas, to the deepest, darkest parts of the forest.

In harsher conditions, the plants will often remain small but still produce seed, and in very wet and sunny locations, the plant can grow up to three feet in height.

Sometimes, invasive species are introduced to a new location to serve a specific purpose. Kudzu, for example, arrived in the U.S. as part of the Philadelphia Centennial Exposition in 1876. Shortly thereafter, it could be ordered by mail and was touted as an excellent animal forage. By the early 1930s, and as late as the early 1950s, kudzu was being distributed by government agencies to control erosion. Japanese Stilt-grass, on the other hand, was accidentally introduced through its use as dry packing material for porcelain. It was first identified in the U.S. in 1919 outside Knoxville, Tenn., and it had spread to North Carolina by 1933. Stilt-grass is now wide spread and one of the most invasive plant species across the eastern United States.

Among a suite of studies conducted by Coweeta LTER scientists was an analysis of published research on stilt-grass to understand why the plant thrives in some habitats, and how that knowledge might be used to reduce the plant’s spread. That research suggests that sites where stilt-grass is most productive may supplement the plants presence at less productive sites.

If true, this may suggest that focusing control efforts at the sites most invaded by stilt-grass will help control the plant over larger areas. However, currently there is no effective, widespread management approach for stilt-grass invasions.

In the meantime, Coweeta LTER researchers are active among a community of researchers trying to understand how stilt-grass invasions may be changing our forests. Their work suggests that stilt-grass may be negatively affecting forest fertility, and work conducted in Georgia suggests the plant may negatively affect habitat for wildlife such as frogs and salamanders.

Without an effective way to control stilt-grass, the most important thing we can do now is to reduce the plant’s spread. Stilt-grass is commonly spread along roadsides by mowing and road maintenance.

Minimizing disturbance to invaded sites may limit growth and seed production, and taking care not to move soils from areas invaded by stilt-grass may limit the plant’s spread to new sites.

 

This column is produced by members of the Coweeta Listening Project (CLP), a branch of the Coweeta Long Term Ecological Research Program. Views expressed here are not representative of the USDA Forest Service or the Coweeta Hydrologic Lab. Please share questions, comments, or suggestions for future topics at cwtlistn@uga.edu or Coweeta Listening Project, UGA, 210 Field St., Room 204, Athens, Georgia 30602.

 

Original Citation: Coweeta Listening Project. The Franklin Press. Column on "Science, Public Policy, Community." Page B4. January 10, 2014.