Sandy Bottomland
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
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Transition T1A
Excessive grazing.
More details
Lack of fire. -
Restoration pathway R2A
Brush management.
More details
Prescribed grazing.
Prescribed fire. -
Transition T2A
Excessive grazing.
More details
Lack of fire. -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference State is defined by three native plant communities that are a result of periodic fire (or lack of fire), drought, herbivory, and ungulate grazers (or non-use). These events are part of the natural disturbance regime and climatic process that contribute to the development of the site. The Reference Plant Community (1.1) consists of tall and mid, warm- and cool-season grasses, forbs, and shrubs. This plant community is dominated by warm-season tallgrasses. The 1.2 Community is dominated by blue grama and sand sagebrush, and is at risk of exceeding the resilience limits of the Reference State and transitioning to the Shrub State (State 2). The 1.3 Community resembles the Reference Plant Community with lower plant density and excessive amounts of litter.
A loss of plant cover and an increase in bare ground creates the probability of wind erosion. Drought-induced wind scouring coupled with disturbance (wildfire, heavy, continuous grazing, rodents, and vehicle traffic) can lead to accelerated erosion.
The following paragraphs are narratives for each of the described plant communities. These plant communities may not represent every possibility, but they probably are the most prevalent and repeatable plant communities that exist on this ecological site. The associated species composition table has been developed from the best available knowledge at the time of this revision. As more data is collected, some, of these plant communities may be adjusted or removed, and new ones may be added.
Submodel
Description
The Shrub State develops due to heavy, continuous grazing that does not allow adequate recovery opportunity between grazing events. It is defined by one plant community phase.
The Reference State has been driven beyond the limits of ecosystem resilience and has crossed a threshold to the Shrub State. The designation of the Shrub State denotes changes in plant species composition. This change in plant species affects the hydrology, erosion potential, forage production, and wildlife habitat. Understory plants may be negatively affected by shrubs reducing the availability of light, soil moisture, and soil nutrients. As the size and density of shrubs increase, the cover and productivity of understory plants decrease.
As establishment of shrubs increase, fine-fuel loads decrease. Prescribed fire can become an ineffective tool to eradicate or decrease the shrubs due to the lack of fine fuel loads.
Submodel
Description
The Eroded State is characterized by two plant community phases that are the result of long-term heavy, continuous grazing without adequate recovery opportunity between grazing events. The development of this state indicates an ecological threshold has been crossed as a result of the disturbance.
The designation of the Eroded State denotes changes in infiltration, runoff, aggregate stability, and species composition. The changes in water movement and the plant community affect changes in hydrologic functionality, biotic integrity, and soil and site stability. Infiltration, runoff, and soil erosion vary depending on the vegetation present.
Submodel
Mechanism
The triggers for this transition are excessive grazing and lack of fire. The biotic integrity and soil and site stability of the site are the impaired ecological processes.
Mechanism
Management actions required to recover the Reference State include the removal of sand sagebrush to appropriate levels of canopy cover together with prescribed grazing and proper stocking. Prescription fire might or might not be an option due to the lack of a fine fuel load. Chemical treatment of sand sagebrush is an option. Precaution and care should be taken when attempting this treatment method. The residual ecosystem properties, such as seed sources, species composition, nutrient content, and hydrologic properties, greatly influence the rate and probability of successful restoration. Brush management alone will not restore this site, and is only supplemental to prescribed grazing for this restoration pathway. Recommendations include a consultation and field evaluation prior to undertaking restoration activities.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Brush Management |
|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Mechanism
Long-term heavy, continuous grazing without adequate recovery periods between grazing events, and a lack of prescribed fire are the drivers that cause the loss of state resilience and result in a shift between the Shrub State and the Eroded State. Ecological functions have been compromised. The effects of this ecological threshold being crossed include changes in aggregate stability, nutrient availability, plant cover, and hydrologic function. Accelerated wind erosion is a concern.
Model keys
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Ecological sites
Major Land Resource Areas
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.