WWETAC Projects
Project Title: Prescribed fire regime and grazing effects on understory vegetation and exotic invasive plants
JFSP ID: 06-2-1-10
Status: Completed
Principal Investigators: Becky K. Kerns, Pacific Northwest Research Station, Western Wildland Environmental Threat Assessment Center, Prineville, OR 97754
Collaborators: Walt Thies, USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331
E-mail Contact: bkerns[at]fs.fed.us
Summary: Ponderosa pine is a major forest type
in western North America and a key focus of prescribed fire and
fuel reduction treatments. However, prescribed fires now interact
with present environmental conditions that are very different
than historical conditions. Fire is being returned to landscapes
where exotic plants are often present and exotic livestock graze.
Tree densities and fuel loading are typically excessive, native
species may have tenuous or declining populations and native
seed banks may be lacking. In addition, prescribed fires may
be applied
temporally outside the historical range of variability. Because
species differ in the timing of peak sensitivity and response
to
burning, vegetation patterns in response to fire can differ by
season of burn. We hypothesize that grazing will detrimentally
affect understory abundance in response to the fires, but that
effects would be linked to species life history characteristics
and known grazing preferences. We also expect major exotic species
in the study area, Bromus tectorum, (downy cheatgrass) to increase
following the fires, and that exotics in general would be less
abundant in areas excluded from grazing. In addition to hypothesis
testing, we explore plant community patterns in relation to
season
and severity of prescribed fire, grazing, forest structure, substrate,
and environmental heterogeneity.
Project ID: FY05BK3
