PARENT SESSION
Symposium #14: Fire and invasive plant ecology and management: the need for integration to effectively restore ecosystems.
Organized by: M Brooks and M Pellant
Tuesday, August 6. 1:00 PM to 4:30 PM. Turquoise Ballroom, TCC.
Impact of fire management practices on invasive plants.
Keeley, Jon*,1,2, 1 U.S. Geological Survey, Three Rivers, CA2 Department of Organismic Biology, Ecology and Evolution, Los Angeles, CA
ABSTRACT- Fire management practices including prescription burning and pre-fire fuel manipulations have the potential for both negative and positive impacts on alien plant invasions. Prescribed burning is increasingly being used under prescriptions designed to reduce populations of target species that are considered particularly noxious weeds, often with significant success. Prescription burning is also being used as a tool in ecosystem restoration and dependent upon conditions, may inhibit or promote alien populations. Restoring fire to coniferous forests after a century of fire suppression is being widely considered throughout the Western U.S. While fire has historically been a natural ecosystem process in these forests, it is now being returned to a landscape with an alien flora often poised for colonization of any disturbance, including natural fire regimes. In the Sierra Nevada mixed conifer forests there is clear evidence that fire behavior vis a vis fire severity may have substantial impacts on the invasion process. In addition, the proximity of seed sources prior to burning plays a key role in determining invasion success. Prefire-fuel manipulations may likewise contribute to alien invasions. For example, fuel breaks may act as invasive corridors carrying alien species into uninfested wildland areas. Following fire, the reduced fuels in fuel breaks contribute to enhanced survivorship of alien seed banks, resulting in source populations poised for invasion of adjacent burned sites. These aliens have the potential for niche construction through their maintenance of flashy fuels, which increase the frequency of burning and in turn favor further alien expansion.
KEY WORDS: Fire, Forests, Grassland, Chaparral