She adds, "Cheatgrass leaves a continuous cover, which is why it may burn more frequently. The native vegetation in such dry landscapes is often shrubby and separated by bare soil, which can stop a fire, but cheatgrass forms a continuous fuel."
Balch points out that one of the consequences of more widespread cheatgrass fires is that landscapes dominated by it have a shorter fire-return interval, the time between fires in a region. For cheatgrass-dominated areas it is 78 years, compared to a 196-year interval in areas dominated by another species such as sagebrush.
"What's happening is that cheatgrass is creating a novel grass-fire cycle that makes future fires more likely," Balch explains. "Fire promotes cheatgrass and cheatgrass promotes fires. And cheatgrass-influenced fires create a difficult management challenge." They can threaten agricultural lands, residential areas as well as habitat for vulnerable native wildlife.
The new information from this study will be useful to management agencies in the West, Bradley says. "Managers have until now been trying to model fire risk under future climate and development conditions without any information on cheatgrass's influence. So now they have one more tool to introduce more information and accuracy into their models."
In the future, the research team hopes to use this regional approach to learn more about how different landscape types such as shrub, forest and wetland ecosystems respond to climate on a yearly basis. "Using remote sensing we can relate climate conditions to fire response and ecosystem phenology over time, and potentially predict how those ecosystems might be affected by consistently warming temperatures in the future," Bradle
|Contact: Janet Lathrop|
University of Massachusetts at Amherst