FRRR Draft PEIS Virtual Public Meeting
3: What are the Desired Vegetation Conditions?
Desired Conditions
Intact and healthy sagebrush communities have a mix of sagebrush, perennial grasses and forbs, better known as wildflowers.
Naturally, sagebrush communities have a mix of sagebrush stands and more open grasslands with scattered shrubs. Historically, infrequent wildfires would burn some thicker stands of sagebrush and leave grasslands with scattered sagebrush. Slowly, the scattered sagebrush would reproduce and establish thicker stands of sagebrush across the landscape. This process maintained a mosaic of sagebrush stands and more open grasslands within the Great Basin. See Section 2.2.9 of the FRRR Draft PEIS for more information about desired conditions and associated vegetation states.
Desired condition bunchgrass community
Vegetation States Outside of Desired Condition
Grasses and Forbs
Cheatgrass dominated community
The vegetation states in the analysis area represent the greatly diminished flora of the sagebrush ecosystem due to expansion of flammable invasive annual grasses at lower elevations (increased fire frequency) and pinyon-juniper encroachment at higher elevations (reduced fire frequency).
In many places, repeated fire in areas with shortened fire return intervals has allowed introduced species such as cheatgrass and other invasive annual grasses, including, but not limited to, medusahead and ventenata to replace sagebrush communities. Degraded areas with a reduced cover of perennial grasses, such as those that have been heavily grazed, are more susceptible to the invasion of annual grasses, such as cheatgrass, as well as the encroachment of pinyon-juniper woodlands.
Trees and Woody Species
Pinyon-juniper trees are expanding into higher elevation sagebrush communities. The borders between sagebrush communities and pinyon-juniper woodlands are naturally fluid and constantly shifting. Pinyon-juniper slowly spreads into sagebrush communities and increases in density until wildfire kills pinyon-juniper and transitions the area back toward a sagebrush community.
In many areas of the Great Basin, fire suppression at higher elevations has allowed sagebrush communities to transition to stands of pinyon-juniper. If pinyon-juniper becomes too dense sagebrush cannot survive in the understory and may be completely lost from an area. See the fifth paragraph of Section 2.2.9 of the FRRR Draft PEIS for more information.
Pinyon-juniper encroaching on sagebrush
The encroachment of pinyon-juniper woodlands is described as successional phases, which proceed from shrub- and herb-dominated communities to woodland-dominated communities. These successional phases are used to determine appropriate vegetation management treatments. Pinyon-Juniper Phase I is represented as a shrub- and herb-dominated community, where trees may be present but make up less than 10 percent of the canopy cover. In Pinyon-Juniper Phase II, trees and shrubs are codominant and the tree canopy ranges from 10 to 30 percent. In Pinyon-Juniper Phase III, the trees are the dominant vegetation and tree canopy cover is greater than 30 percent. See Section 3.1.2 of the FRRR DPEIS for more information.
The vegetation states in the analysis area relate to a relative amount of sagebrush, perennial grass and forb, invasive annual grass and/or pinyon-juniper foliar cover. The percent cover of each category was divided into low, medium, and high cover classes (and an intermediate class for shrubs). Vegetation states are described in the table below.
Description of Vegetation States within the Analysis Area
For more information on the FRRR Draft PEIS please contact Ammon Wilhelm, 208-373-4000.
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