Breaks 12-18" PZ
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Transition T1B More details
- Restoration pathway R2A More details
- Restoration pathway R2B More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Grassland/Shrub State
Description
The plant community composition most prevalent on the xeric (south and west facing slopes) aspect of breaks site is grasses forbs = shrubs trees. The majority of the grasses are drought-tolerant short-grass species. In general, grasses make up 55 to 65 percent of total production; forbs make up 10 to 20 percent; shrubs make up 10 to 20 percent; and trees make up 5 to 10 percent. Juniper is often the only tree species present and is usually scattered.
The reference plant community constitutes a diverse mixture of grasses, forbs, and shrubs found on a north-facing slopes of about 35 to 40 percent. This would be the assumed HCPC for the mesic aspect of the Breaks site (1.1). Sandstone boulders comprise approximately 35-40 percent of surface cover. Production is high for this site and the site is very stable. There is a notable absence of juniper on this particular area. However, there are some small colonies of juniper close by. Total annual production ranges from 395 to 480 pounds per acre.
Natural fire did influence the historic plant community development on many of the Breaks areas in this MLRA. It is believed that fire suppressed some of the woody vegetation that is now dominant in many of these areas. Oneseed juniper is especially susceptible to damage by fire, and this species has greatly increased from HCPC populations, largely due to natural fire being suppressed by various factors and for various reasons.
The Grassland/Shrub Community (1.2) is representative of the xeric aspect of the Breaks site. This is a southwest facing slope of approximately 35 percent that is dominated by short- and mid-grasses with few forbs and scattered shrubs. A few trees (oneseed juniper) may be present.
No natural fire over a period of 20 or more years will tend to shift the mesic plant community (1.1) towards the Woodland/Grassland Community (2.1).
Submodel
State 2
Shrubland State
Description
Grassland State has been converted to a Shrubland State. Juniper has increased from 10 to 15 percent to greater than 30 percent canopy cover. There is a reduction of perennial forbs and short-grasses. There are more short-grasses than mid-grasses present. The dominant grasses are black grama and hairy grama, with a lesser amount of sideoats grama on the lower slopes. The densest canopies occur on the north/northeast slopes. Once juniper canopy exceeds 30 percent, prescribed burning will be ineffective due to the lack of fine fuel. Prescribed burning must be performed before juniper canopies reach 30 percent.
Submodel
Mechanism
This transition occurs from 1.1 Grassland/Shrub (Mesic Aspect) to the 2.1 Woodland/Grassland Community. The lack of natural fires over a 20 year period, as well as the lack of brush management treatments, have allowed for a moderate increase in juniper.
Mechanism
This transition occurs from 1.2 Grassland/Shrub (Xeric Aspect) to the 2.2 Grassland/Woodland Community. No natural fires or prescribed burns over a 50 year period and no brush management treatments has allowed for a dramatic invasion of juniper.
Mechanism
This restoration occurs from 2.1 Woodland/Grassland Community (Mesic) to the 1.1 Grassland/Shrubland (Mesic Aspect). Prescribed Burning (2 or more burns over a 15 to 20 year period), Prescribed Grazing, or Prescribed Burning combined with Brush Management (Individual Plant Treatments).
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Mechanism
This restoration occurs from 2.2 Grassland/Shrubland with 10-15% woody canopy (Xeric Aspect) to the 1.2 Grassland/Shrubland (Xeric Aspect). Prescribed Burning ( single burn over a 5-6 year period), follow up Brush Management (Individual Plant Treatment) and Prescribed Grazing over a 5-6 year period.
Model keys
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The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.