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Wildlife, Animals, and Plants |
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FIRE ECOLOGYFIRE ECOLOGY OR ADAPTATIONS:Fire regime | Mountain Big Sagebrush : Presettlement fire return intervals in mountain big sagebrush communities varied from 15 to 25 years [22,155,157]. For example, mountain big sagebrush sites in southwestern Idaho show evidence of about 3 to 5 fires per century prior to 1910 [23]. Very frequent fire suppresses mountain big sagebrush establishment, while long fire return intervals promote tree invasion into mountain big sagebrush communities. Arno and Gruell [3] considered average fire intervals of about 20 years sufficient to control mountain big sagebrush invasion in southwestern Montana grasslands. Fire exclusion has led to invasion of mountain big sagebrush communities by western juniper [22,156,157]. Mountain big sagebrush can be a nurse plant for western juniper. On a southeastern Oregon site, less than 20% of western juniper seedlings established in the open; the rest were under mountain big sagebrush or low sagebrush plants [156]. Sparse under presettlement fire frequencies of 15 to 25 years, western juniper has formed dense stands on former mountain big sagebrush communities in the Great Basin [22,156,157]. Miller and others [157] found that on southeastern Oregon and northeastern California sites, mountain big sagebrush cover declined to 80% of maximum potential as western juniper cover increased to 50% of maximum canopy cover. Herbaceous cover and species diversity declined, and bare ground cover increased, with increasing western juniper dominance. Burkhardt and Tisdale [23] concluded that fire frequencies of 30 to 40 years would control western juniper expansion onto mountain big sagebrush communities. Fire regimes for communities in which mountain big sagebrush occurs are summarized below. For further information about fire regimes and fire ecology of communities where mountain big sagebrush is found, see the 'Fire Ecology and Adaptations' section of the FEIS species summary for the plant community or ecosystem dominants.
**(mean) Fire adaptations | Mountain Big Sagebrush : Mountain big sagebrush is readily killed by fire and requires
at least 15 years to recover
after fire [18]. Postfire establishment is from
seed. Data from 1 study suggest that germination is stimulated by fire. Champlin [27] reported that
mountain big sagebrush seedling emergence under greenhouse conditions was greater in field-burned (in situ) soil samples than in unburned soil samples. By contrast, seedling emergence of Wyoming big sagebrush was reduced in burned soils. Possible explanatory mechanisms might be related to those explored by Blank and Young [12]. They observed that smoke and compounds present in aqueous extracts of heated soils from beneath a sagebrush canopy increased the emergence of common associated plant species, though big sagebrush seeds were not among those tested. POSTFIRE REGENERATION STRATEGY [117]:
Ground residual colonizer (on-site, initial community)
Related categories for SPECIES: Artemisia tridentata spp. vaseyana | Mountain Big Sagebrush |
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