Most of the coastal prairie has been converted to agricultural land over the past century. One of the difficulties in protecting remaining prairie habitat, says Grace, is that wildfires can no longer spread across wide areas. The prairie is in pieces, and consequently, for fire to continue to play its life-sustaining role it must be carefully managed.
As the prairie habitat becomes fragmented and the natural fire regime disrupted, the danger of invasion by exotic species increases, says Grace. The most immediate threat to the coastal prairie today is an invasive tree species known as Chinese tallow. While this species has been around since the 1700s, it has greatly expanded over the past century. The population explosion has proceeded over the last 80 years, and now it has reached clearly catastrophic levels, says Grace.
In his studies of how fire can be used in coastal prairie ecosystem restoration, Grace has come to focus much of his attention on how the Chinese tallow invasion can be controlled. Once tallow takes over an area, he said, it is extremely hard to eradicate, and its dense stands shade out the native prairie plants. "It's incredible the degree to which tallow eliminates all the herbaceous vegetation," says Grace. "The ground ends up completely bare of other vegetation."
Making matters worse is the fact that Chinese tallow is extremely fire
resistant. In a natural community, when there is an accumulation of woody
vegetation, fire can come along and burn it out, says Grace. Chinese tallow,
however, makes the ecosystem non-flammable. "There's no real way to recover once
the tallow stands
Contact: Catherine Haecker
United States Geological Survey