• FIRE ECOLOGY OR ADAPTATIONS
• POSTFIRE REGENERATION STRATEGY

FIRE ECOLOGY OR ADAPTATIONS:

Spotted knapweed occurs primarily in bunchgrass and open ponderosa pine forest community types in the Intermountain West, especially Montana. The historical fire regimes of these communities were relatively frequent, low-severity surface fires. Spotted knapweed did not occur in these communities at the time in which these fire regimes were functioning, but has established since fire exclusion began. It is unclear how this type of fire regime might affect spotted knapweed populations. It is also unclear how the presence of spotted knapweed might affect these fire regimes, though it has been observed that spotted knapweed does not carry fire as readily as grasses. Therefore, dense knapweed infestations can change the fire regime by changing the fuel characteristics and thus reducing the fire return interval at a given site [122,235].

The following table provides fire regime intervals for communities and ecosystems in which spotted knapweed most commonly occurs:

Community or Ecosystem	Dominant Species	Fire Return Interval Range (years)
grand fir	Abies grandis	35-200 [9]
sagebrush steppe	Artemisia tridentata/Pseudoroegneria spicata	20-70
plains grasslands	Bouteloua spp.	< 35
western juniper	Juniperus occidentalis	20-70
Rocky Mountain juniper	J. scopulorum	< 35 [144]
western larch	Larix occidentalis	25-100
Engelmann spruce-subalpine fir	Picea engelmannii-Abies lasiocarpa	35 to > 200 [9]
pinyon-juniper	Pinus-Juniperus spp.	< 35 [144]
Rocky Mountain lodgepole pine*	P. contorta var. latifolia	25-300+ [6,9,166]
Colorado pinyon	P. edulis	10-49 [144]
interior ponderosa pine*	P. ponderosa var. scopulorum	2-10 [9]
red pine (Great Lakes region)	P. resinosa	10-200 (10**) [32,41]
eastern white pine	P. strobus	35-200
eastern white pine-northern red oak-red maple	P. strobus-Quercus rubra-Acer rubrum	35-200 [218]
mountain grasslands	Pseudoroegneria spicata	3-40 (10**) [6,9]
Rocky Mountain Douglas-fir*	Pseudotsuga menziesii var. glauca	25-100 [9]
oak-juniper woodland (Southwest)	Quercus-Juniperus spp.	< 35 to < 200 [144]
northern red oak	Q. rubra	10 to < 35 [218]
elm-ash-cottonwood	Ulmus-Fraxinus-Populus spp.	< 35 to 200 [32,218]

*fire return interval varies widely; trends in variation are noted in the species summary
**mean

POSTFIRE REGENERATION STRATEGY [186]:

Related categories for SPECIES: Centaurea stoebe ssp. micranthos | Spotted Knapweed