Invasive grass may impede forest regeneration

April 9, 2007

The nonnative invasive grass Microstegium vimineum may hinder the regeneration of woody species in southern forests. Chris and Sonja Oswalt (Forest Service Southern Research Station) and Wayne Clatterbuck (University of Tennessee) set up experiments on a mixed-hardwood forest in southwest Tennessee to study the growth of the invasive grass under different levels of forest disturbance. Study results were published online in the journal Forest Ecology and Management on March 27, 2007.

M. vimineum, commonly called Nepalese browntop or Japangrass, was first identified in 1919 near Knoxville, Tennessee, where it was inadvertently introduced in packing material for porcelain china. Since then, the grass has spread across the southern States, flourishing on floodplains and streamsides and displacing native vegetation.

"Microstegium can invade and persist in the low-light conditions of interior forests, making excellent use of short bursts of sunlight," says Chris Oswalt. "It can also flourish in the full light conditions that follow many canopy disturbances."

While working on a larger oak regeneration study at The Ames Plantation in southwest Tennessee, the researchers noticed a dramatic increase in Microstegium after silviculture treatments that opened the forest canopy. To test whether the grass would negatively impact the regeneration of native woody species, they conducted a separate set of studies nested within the silvicultural study with treatments that ranged from no disturbance to complete canopy removal.

After a season of monthly vegetation measures on a total of 720 plots, the researchers found that although Microstegium biomass did not differ significantly among silviculture treatments, there was a significant difference between treated and undisturbed plots, with Microstegium biomass 2 to 10 times greater in disturbed plots. They also found that the species richness of native woody species on the disturbed plots declined as the percent of Microstegium cover increased.

"We found that when exposed to sunlight, Microstegium can grow rapidly, often forming thick organic mats on the forest floor that directly impede the regeneration of native woody species by blocking sunlight, and indirectly by blocking seeds from reaching the soil in order to germinate," says Chris Oswalt. "This grass, which can be easily overlooked in the understory, should be given more attention by both researchers and land managers."

Source: Southern Research Station - USDA Forest Service

Explore further: Shale gas development spurring spread of invasive plants in Pa. forests

Related Stories

Controlled burns increase invasive grass in hardwood forests

July 21, 2015

Controlled burning is widely used to maintain biodiversity and enhance regeneration of important deciduous tree species such as oak and hickory, but a recent University of Illinois study found that this practice also increases ...

Recommended for you

New bioimaging technique is fast and economical

August 18, 2017

A new approach to optical imaging makes it possible to quickly and economically monitor multiple molecular interactions in a large area of living tissue—such as an organ or a small animal; technology that could have applications ...

Hot spot at Hawaii? Not so fast

August 18, 2017

Through analysis of volcanic tracks, Rice University geophysicists have concluded that hot spots like those that formed the Hawaiian Islands aren't moving as fast as recently thought.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.