Upland Stony Loam (basin big sagebrush-saline wildrye)

Description

This state describes the biotic communities that may become established on this ecological site if all successional sequences are completed under natural disturbance conditions. The reference state has a well developed shrub layer with basin big sagebrush often dominating. Wyoming big sagebrush, shadscale and slender buckwheat are other common shrub species. Salina wildrye is the dominant herbaceous species with Indian ricegrass and bluebunch wheatgrass commonly found also. Other native grasses, forbs, and shrubs may produce significant composition in the plant community.

This site occurs on very steep (50 to 85%) slopes with an aspect that is typically northeasterly. It is usually found directly below vertical canyon rims and above valley floors. Its soils are extremely stony and/or gravelly, somewhat limiting site production.

The primary disturbance mechanisms are shrub layer density, weather fluctuation, and fire. The reference state is self sustaining and resistant to change due to a high resistance to natural disturbances and a high resilience following those disturbances. When natural disturbances occur, the rate of recovery can be quite variable.

Reference State: Plant communities influenced by shrub canopy density, long term weather fluctuations, and periodic fire.

Indicators: A community dominated by basin big sagebrush and Salina wildrye. The density of the shrub canopy determines the amount and composition of the other native perennial grasses and forbs that may be present.

Feedbacks: Natural fluctuations in weather patterns that allow for a self sustaining shrub and native grass community. Prolonged drought, more frequent fires, or other disturbances that may allow for the establishment of invasive species.

At-risk Community Phase: All communities are at risk when native plants are stressed and nutrients become available for invasive plants to establish.

Trigger: The establishment of invasive plant species.

Submodel

Description

The Current Potential State is similar to the Reference Sate except that non-native species are now present. This state describes the plant communities that may become established on this ecological site if all successional sequences are completed under natural disturbance conditions. This state has a well developed shrub layer with basin big sagebrush often dominating. Wyoming big sagebrush, shadscale and slender buckwheat are other common shrub species. Salina wildrye is the dominant herbaceous species with Indian ricegrass and bluebunch wheatgrass commonly found also. Other native grasses, forbs, and shrubs may produce significant composition in the plant community. Cheatgrass, alyssum, and other non-native species are present on the site especially along its lower slopes.

This site occurs on very steep (50 to 85%) slopes with an aspect that is typically northeasterly. It is usually found directly below vertical canyon rims and above valley floors. Its soils are extremely stony and/or gravelly, somewhat limiting site production.

The primary disturbance mechanisms are shrub layer density, the amount of invasive species present, weather fluctuation, and fire. The current potential state is still self sustaining but may be losing its resistance to change due to a lowered resistance to natural disturbances and less resilience following those disturbances. When natural disturbances occur, the rate of recovery can be quite variable.

Reference State: Plant communities influenced by shrub canopy density, long term weather fluctuations, and periodic fire.

Indicators: A community dominated by basin big sagebrush and Salina wildrye. The density of the shrub canopy determines the amount and composition of the other native and introduced grasses and forbs that may be present.

Feedbacks: Natural fluctuations in weather patterns that allow for a self sustaining shrub and native grass community. Prolonged drought, more frequent fires, or other disturbances that may allow for the increase of invasive species.

At-risk Community Phase: All communities are at risk when native plants are stressed and nutrients become available for invasive plants to increase.

Trigger: The establishment of invasive plant species. Few disturbed sites have been located to date and so little data exists regarding them.

Submodel