Clay Slopes 25-28" PZ
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Absence of disturbance and natural regeneration over time, may be coupled with excessive grazing pressure
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Transition T1B
Extensive soil disturbance followed by seeding
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Restoration pathway R2A
Adequate rest from defoliation, followed by reintroduction of historic disturbance regimes
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Transition T2A
Absence of disturbance and natural regeneration over time, may be coupled with excessive grazing pressure
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Transition T2B
Extensive soil disturbance followed by seeding
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Restoration pathway R3A
Adequate rest from defoliation and removal of woody canopy
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Transition T3A
Extensive soil disturbance followed by seeding
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Restoration pathway R4A
Natural regeneration over time coupled with excessive grazing pressure
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
State 1
Mid/Tallgrass State
Description
The Midgrass/Tallgrass Community is the reference plant community. In pristine conditions it is an open prairie dominated by midgrasses, scattered tallgrasses, some perennial forbs, and a few widely scattered shrubs. Sideoats grama and vine mesquite are the most abundant grasses. Tallgrasses such as big bluestem and Indiangrass may be found on the upslopes of the site or in areas with more open soil profiles. Woody canopy is less than 5%. Widely scattered shrubs and small trees include skunkbush sumac, catclaw acacia, lotebush, and hackberry.
The Midgrass Community is totally dominated by midgrasses. A viable population of primary midgrasses still persists, but other midgrasses such as silver bluestem, Texas wintergrass, and dropseeds increase significantly. Early successional forbs and shortgrasses such as curlymesquite, buffalograss, and western ragweed begin to increase. The canopy of shrubs and trees begins to gradually increase as mesquite, pricklypear, lotebush, and similar species encroach from adjacent areas. Little bluestem and other tallgrasses are eliminated or severely reduced but may still be found in remote or protected areas. Woody canopy of shrubs and trees is less than 10%.
Submodel
State 2
Mixedgrass State
Description
In the Midgrass/Shortgrass Community, primary midgrasses including sideoats grama, vine mesquite, and Arizona cottontop decline drastically and little bluestem and other tallgrasses are almost completely eliminated from the site. Midgrasses such as silver bluestem, dropseeds, and white tridens increase significantly. Shortgrasses such as curlymesquite, buffalograss, hairy grama, and slim tridens increase and become co-dominant with midgrasses. Woody canopy increases to as much as 15%. Texas wintergrass increases as the woody canopy increases.
The Shortgrass/Annuals Community is experiencing continued deterioration of the plant community which eventually results in a plant community characterized by shortgrasses such as buffalograss, curlymesquite, threeawns and Texas grama, encroachment of annual grasses and forbs, an increase in shrubs, and an increase in bare ground. Western ragweed and broomweed are the dominant forbs. Mesquite, catclaw acacia, lotebush, pricklypear, and other shrubs increase in density or invade from adjacent sites. Woody canopy increases to approximately 20%. Texas wintergrass becomes the dominant midgrass as the density and canopy of shrubs continues to increase.
Submodel
Description
The Shrubland Community is dominated by non-native and invasive native shrubs such as mesquite, catclaw acacia, lotebush, pricklypear, and tasajillo with a canopy of 25% or more. The woody canopy has a noticeable detrimental effect on the understory vegetation. Extensive areas of bare ground may occur. Shortgrasses as well as annual grasses and forbs, and early successional midgrasses increase dramatically and invade from adjacent sites. Texas wintergrass and other shade tolerant species will also increase. If fields are abandoned and left to re-vegetate naturally, weedy grasses, forbs and shrubs will become established.
Submodel
Description
Since the site generally occurs as small irregularly shaped areas, the Converted Land State Community is usually treated and managed in conjunction with surrounding sites. Kleingrass, Old World bluestem, and King Ranch bluestem are the most commonly seeded introduced grasses, but some areas have been planted to Bermudagrass. The areas that have been converted to cropland are primarily planted to wheat, oats, or forage sorghum. After conversion to other land uses, these areas must be intensively managed in order to maintain production and quality. Production potential for seeded species and crops is moderately high.
The Abandoned Community occurs when over time, many of these cultivated and intensively managed areas have been abandoned because of adverse economic conditions. Adverse economic conditions, drought, and other outside factors may result in these areas being abandoned or neglected. If fertility is not maintained, and weed control is not routinely carried out, the land will tend to revert to early successional plants such as annual forbs and grasses. These abandoned lands have deteriorated to the point that they will never return to historical vegetation because of soil degradation and lack of natural seed source.
Submodel
Mechanism
Continued abusive grazing practices and a lack of fire will eventually result in further deterioration of the midgrass plant community. This decline may be intensified or accelerated by drought conditions and/or failure to carry out maintenance brush management practices. As a result of this level of mismanagement, little bluestem and other tallgrasses are eliminated from the site except for remnant plants that are protected. Sideoats grama, vine mesquite, and Arizona cottontop are drastically reduced. Silver bluestem, meadow dropseed, and white tridens become the dominant midgrasses. Shortgrasses including curlymesquite, buffalograss, hairy grama, and slim tridens increase significantly and become co-dominants. Non-native and invasive native shrubs begin to increase on the site and invade from adjacent sites. The increase in density and woody canopy of shrubs begins to have an adverse effect on the understory herbaceous vegetation because of increased shading and competition for space and soil moisture. Texas wintergrass begins to increase significantly as the woody canopy increases.
Mechanism
This plant community can be converted to cropland or seeded introduced grasses or commercially available native grasses. Because the site usually occurs as small irregularly shaped areas, it is usually treated and managed in conjunction with surrounding sites. Kleingrass, Old World bluestem, and King Ranch bluestem are the most commonly seeded introduced grasses, but some areas have been planted to bermudagrass. The areas that have been converted to cropland are primarily planted to wheat, oats, or forage sorghum. Seedbed preparation can be accomplished with normal cultivation equipment and desired vegetation can be seeded or planted. This is a terminal state because the soil has been altered and the historic plant species no longer exist on the site.
Constraints to recovery
Extensive soil disturbance followed by seeding
Mechanism
At this stage, there is no longer a viable population of the original primary midgrasses and tallgrasses to reproduce sufficient seed to enable the plant community to recover through management practices alone. Range planting is needed to re-introduce the desired midgrass and tallgrass species back into the plant community. Implementation of a grazing management plan is necessary to allow establishment of seeded vegetation and control the timing, frequency, duration, and degree of grazing following establishment. Brush management is needed when the density and canopy of shrubs and trees begins to have an adverse effect on the desired grasses and forbs. Periodic prescribed burning is needed to keep woody species under control, encourage diversity in the grass and forb plant community, and assist with the recovery and maintenance of the desired plant community.
Relevant conservation practices
| Practice | External resources |
|---|---|
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Brush Management |
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Prescribed Burning |
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Prescribed Grazing |
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Range Planting |
Mechanism
Continuous abusive grazing, lack of fire, and extended drought can all be major factors in the deterioration of the plant community from an open prairie to a shrub dominated site. The site is dominated by non-native and invasive native shrubs with a canopy of 25% or more. The woody canopy has a noticeable detrimental effect on the understory vegetation. Extensive areas of bare ground may occur. Shortgrasses as well as annual grasses and forbs, and early successional midgrasses increase dramatically and invade from adjacent sites. Texas wintergrass and other shade tolerant species increase. The site is highly susceptible to water erosion. Once the site has declined to this stage, it will not return to a higher state of vegetation through management practices alone.
Mechanism
This plant community can be converted to cropland or seeded introduced grasses or commercially available native grasses, but it may require mechanical brush management to remove unwanted shrubs and trees if they are dense enough to interfere with seedbed preparation, seeding or planting operations, or management following establishment. Seedbed preparation methods may require heavier equipment, and seeding or planting methods may have to be modified to overcome more intensive land preparation treatments. Because the site usually occurs as small irregularly shaped areas, it is usually treated and managed in conjunction with surrounding sites. Kleingrass, Old World bluestem, and King Ranch bluestem are the most commonly seeded introduced grasses, but some areas have been planted to Bermudagrass. The areas that have been converted to cropland are primarily planted to wheat, oats, or forage sorghum. Seedbed preparation can be accomplished with normal cultivation equipment and desired vegetation can be seeded or planted. This is a terminal state because the soil has been altered and the historic plant species no longer exist on the site.
Mechanism
It is probably not practical or economically feasible to attempt to restore the reference plant community through brush management and revegetation. In order to have any possibility of recovery from this state, a carefully planned and implemented prescribed grazing management strategy must be implemented, extensive brush management is required, and range planting is necessary to re-introduce perennial grasses and forbs to the plant community. These treatments may result in the re-establishment of establish a perennial grass plant community with most of the primary grasses, but lacking the diversity of forbs and minor grasses found in the reference plant community. This is a difficult, risky, and expensive consideration. If the reseeded areas become established, a prescribed burning management program is needed to maintain balance, diversity, and vigor in the plant community.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
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Prescribed Burning |
|
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Range Planting |
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|
Prescribed Grazing |
Mechanism
This plant community can be converted to cropland or seeded introduced grasses or commercially available native grasses, but extensive brush management is required to clear the land. Seedbed preparation techniques with heavy equipment are required and seeding or planting methods may have to be modified to overcome more intensive land preparation treatments. These treatments are radical, expensive, and generally not recommended. Because the site usually occurs as small irregularly shaped areas, it is usually treated and managed in conjunction with surrounding sites. Kleingrass, Old World bluestem, and King Ranch bluestem are the most commonly seeded introduced grasses, but some areas have been planted to Bermudagrass. The areas that have been converted to cropland are primarily planted to wheat, oats, or forage sorghum. Seedbed preparation can be accomplished with normal cultivation equipment and desired vegetation can be seeded or planted. This is a terminal state because the soil has been altered and the historic plant species no longer exist on the site.
Mechanism
Abusive grazing, lack of fire, lack of brush management, and abandonment are factors that result in these previously treated areas reverting to areas that are dominated by bare ground, annual grasses and forbs, low successional perennial grasses and forbs, and stunted shrubs. The site is highly susceptible to water erosion. In this scenario, this is a terminal state because the soil has been altered and the historic plant species no longer exist on the site.
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.