Upland Shallow Loam (pinyon-Utah juniper)

Submodel

Description

This state is very similar to the reference state, except that non-native grasses and/or forbs are now present in all phases. The current potential state may include naturalized or invasive nonnative species. The primary disturbance mechanisms for this state include natural and human caused disturbances. Drought, insects, and occasional fire still influence the community shifts; however, domestic livestock grazing, recreational activities, and other man caused disturbances now present. Plant communities within the current potential state are more likely managed and used for various purposes by man, with out significant alteration in plant community composition or production. In time, continuous surface disturbances (i.e. improper grazing, off highway vehicles (OHV) use, recreational activities, etc.) will likely stress the native perennial grasses and allow for non-natives species to increase. This shift in species composition could affect nutrient cycling, hydrology and soil stability. At this time there is no known way to effectively remove the non-native plants from the site once they have become established. Therefore, this site is often irreversibly altered from the reference state

Characteristics and indicators

Current Potential State: Community phases maintained by drought, insects, infrequent crown fires, domestic livestock grazing, and vegetation manipulation.

Indicators: A developed understory co-existing with a canopy of older Pinyon and juniper.

Feedbacks: Infrequent, but regular droughts to reduce tree cover, and allow for the establishment of grasses and forbs in the understory. Long fire intervals that result in an increase in tree establishment and loss of the herbaceous understory.

At-risk Community Phase: Communities 2.1 and 2.2 are at risk of moving into State 3 when remaining native understory plants are stressed and introduced species are dominant.

Trigger: Canopy closure and or presence of invasive species have increased to the point where they influence the nutrient cycling and disturbance regime. Seeding of naturalized species after significant amounts of vegetation management or natural disturbance.

Submodel

Description

This state occurs when natural or management actions have allowed trees to become very mature and have effectively closed out the understory. The primary disturbance mechanisms for this state include increased erosion, improper grazing, and other surface disturbances, such as recreational activities. This state has the lowest resiliency and resistance of any state in this description.

Characteristics and indicators

Eroded state: Community phases maintained by time, drought, and erosion.

Indicators: A lack of understory with a canopy of older Pinyon and Juniper, where plant interspaces very large and connected.

Feedbacks: Increased tree establishment, drought, surface disturbances, heavy rainfall, erosion, and loss of biological crusts that facilitate the continued erosion of this site. Infrequent, but regular droughts to reduce tree cover, coupled with adequate moisture to support and increase the herbaceous understory and biological crusts.

At-risk Community Phase: Community 3.1 is most at risk when the biological crusts are severely disturbed. However one this state is reached there may be no feasible way back to the Current Potential State, due to the large amounts of monetary and energy inputs that would be needed.

Trigger: Seeding of naturalized species after significant amounts of vegetation management or catastrophic natural disturbance.

Submodel

Description

This state is a result of a large amount of management actions. The trees were removed and adapted grasses established. This state reflects the desired management goals. If grazing tolerant species were established these communities can better withstand grazing and other disturbances. Due to the shallow soils and unpredictable precipitations patterns, it is difficult to establish grasses from seed, so this state may be hard to achieve.

Characteristics and indicators

Seeded state: Community phases maintained by time without disturbances and vegetation manipulation,

Indicators: A developed perennial herbaceous understory of seeded species, typically non-natives, co-existing with some Pinyon and Utah juniper.

Feedbacks: Moist cycles that maintain perennial bunch grasses. Loss of the herbaceous understory and an increase in tree establishment.

At-risk Community Phase: All communities are at risk if they are allowed to transition into state 3.

Restoration Pathway: Reestablishment of native and introduced species through time and proper management.

Submodel