Talus Slope (Blackbrush-Shadscale)

Description

This Reference State describes the various biotic communities that are expected to be found on this ecological site under natural conditions. Two distinct phases are present and are described below as Wet and Dry Phases.

The Wet Phase has a scattered overstory of Utah juniper with small amount of two-needle pinyon. A wide array of shrubs including Mormon tea, blackbrush, spiny hopsage, and Mexican cliffrose dominate the shrub layer. A well developed grass layer is often present with Indian ricegrass, salina wildrye and James galleta occurring most often. This phase nearly always has a north, northeast or east aspect. It is normally at higher elevations and found in higher precipitation zones or where additional run-on moisture occurs. Its soils typically have higher Available Water Holding Capacity's (AWC) and often have fewer coarse fragments found within the soil profile.

The Dry Phase has little or no Utah juniper or two-needle pinyon present. Primary shrubs include blackbrush, shadscale, Castle Valley saltbush and Mormon tea. Herbaceous species are rare with minor amounts of Indian ricegrass and James galleta usually present. On more sandy soils, spike and mesa dropseed may be present. This phase typically has a south, southwest or west aspect. It is normally at lower elevations and found in lower precipitation zones where little or on additional run-on moisture occurs. Its soils typically have lower Available Water Holding Capacity's (AWC) and often have large amounts of coarse fragments within the soil profile.

The reference state is self-sustaining and resistant to change due to good natural resilience to its natural disturbances. The primary natural disturbance mechanisms are wildlife population densities which can affect the shrub layer composition and weather fluctuations.

Definitions:

Reference State: Natural plant communities as influenced by latitude, elevation, aspect, precipitation (including run-on moisture), soil texture and depth, and the percent of coarse fragments found within the soil profile.

Indicators: These communities are highly variable with a wide array of species present specific of the physical site conditions.

Feedbacks: Natural fluctuations in weather patterns that allow for native species to be self-sustaining and prevent the establishment of invasive species.

At-risk Community Phase: All communities are at risk when native plants are stressed and conditions are created that may allow invasive plants to establish.

Trigger: The establishment of invasive plant species.

Submodel

Description

This Current Potential State describes the various biotic communities that are expected to be found on this ecological site under current conditions. Two distinct phases are present and are described below as Wet and Dry Phases. Both phases now contain invasive species with Russian thistle, various mustard species and knapweed occurring most often.

The Wet Phase has a scattered overstory of Utah juniper with small amount of two-needle pinyon. A wide array of shrubs including Mormon tea, blackbrush, spiny hopsage, and Mexican cliffrose dominate the shrub layer. A well developed grass layer is often present with Indian ricegrass, salina wildrye and James galleta occurring most often. Russian thistle and annual mustard are common invasive species. This phase nearly always has a north, northeast or east aspect. It is normally at higher elevations and found in higher precipitation zones or where additional run-on moisture occurs. Its soils typically have higher Available Water Holding Capacity's (AWC) and often have fewer coarse fragments found within the soil profile.

The Dry Phase has little or no Utah juniper or two-needle pinyon present. Primary shrubs include blackbrush, shadscale, Castle Valley saltbush and Mormon tea. Herbaceous species are rare with minor amounts of Indian ricegrass and James galleta usually present. On more sandy soils, spike and mesa dropseed may be present. Russian thistle and knapweed are commonly occurring invasive species. This phase typically has a south, southwest or west aspect. It is normally at lower elevations and found in lower precipitation zones where little or on additional run-on moisture occurs. Its soils typically have lower Available Water Holding Capacity's (AWC) and often have large amounts of coarse fragments within the soil profile.

The reference state is self-sustaining and resistant to change due to good natural resilience to its natural disturbances. The primary natural disturbance mechanisms are wildlife population densities which can affect the shrub layer composition and weather fluctuations.

Definitions:

Reference State: Natural plant communities as influenced by latitude, elevation, aspect, precipitation (including run-on moisture), soil texture and depth, and the percent of coarse fragments found within the soil profile.

Indicators: These communities are highly variable with a wide array of species present specific of the physical site conditions.

Feedbacks: Natural fluctuations in weather patterns that allow for native species to be self-sustaining and prevent the establishment of invasive species.

At-risk Community Phase: All communities are at risk when native plants are stressed and conditions are created that may allow invasive plants to establish.

Trigger: The establishment of invasive plant species.

Submodel