Closed Depression
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Transition T4A More details
- Restoration pathway R2A More details
- Transition T4A More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference State (1.0) represents what is believed to show the natural range of variability that dominated the dynamics of the ecological site prior to European settlement. This state is co-dominated by cool- and warm-season grasses, grass-likes, and forbs. In pre-European times, the primary disturbance mechanisms for this site in the Reference condition included an annual precipitation cycle resulting in alternating periods of ponding and drying, and as a seasonal watering and grazing resource for large herding ungulates.
Timing of grazing coupled with weather events dictated the dynamics that occurred within the natural range of variability. Today, this state can be found on areas that are properly managed with grazing and possibly prescribed burning, and sometimes on areas receiving occasional short periods of rest. Western wheatgrass can decline and a corresponding increase in foxtail barley, warm-season shortgrasses, and forbs will occur. Under extended periods of disturbance, the main change is a reduction in vigor and production of the vegetation and an increase in bare ground and forb composition. The Reference State (1.0) has two plant communities with two distinct sub-phases as a result of the alternating periods of ponding and drying.
Submodel
Description
The Shortgrass Sod State is dominated by inland saltgrass, foxtail barley, and bluegrass during the drier phase and forbs and grass-like species during the wet phase. This State is the result of heavy, continuous grazing and/or excessive haying, or heavy disturbance which can create soil compaction and increased sodium concentrations on the soil surface. This State, like the Reference State (1.0), will have one plant community (2.1) with two distinct sub-phases as a result of the alternating periods of ponding and drying. The Shortgrass Sod State (1.0) is very resilient and resistant to change.
Submodel
Description
Any plant community can transition to the Disturbed State (3.0). The two separate vegetative plant communities found in this state are highly variable in nature. They are derived through different management scenarios and are not related successionally.
Mechanical manipulation of the watershed causing the loss of hydrologic function, biotic integrity, and soil site stability. Hydrologic function of this site is disrupted through terracing, contour furrowing, or pitting in the area surrounding the closed depression, or the installation of a dugout in the closed depression site. Other causes include, severe mechanical disturbance through tillage and the conversion to cropland or pasture and hayland.
Submodel
Mechanism
Heavy, continuous grazing (grazing at full to heavy levels for extended portions of the growing season without adequate recovery periods); or excessive haying; or heavy disturbance may cause a shift from the Reference State (1.0) to the Shortgrass Sod State (2.0). During the wet cycles prior to soils drying, the Reference Plant Community (1.1) is highly susceptible to compaction if heavy grazing occurs when the soil is saturated. This type of disturbance can cause a rapid decline in the native vegetation and a subsequent influx of non-native forb species to occur.
Mechanism
Heavy disturbance including tillage and cropping; abandonment of cropland; seeding to improved pasture species; or installation of water control structures (terraces or dugouts) will transition any plant community in this ecological site to the Degraded State (3.0).
Mechanism
Removal of the grazing disturbance coupled with long-term prescribed grazing including proper stocking rates, change in season of use, and adequate time for plant recovery following grazing event may shift the Shortgrass Sod State (2.0) to the Reference State (1.0). This transition may not be rapid or in the end meet management goals. Prescribed burning may also be a tool to aid in this transition.
Relevant conservation practices
| Practice | External resources |
|---|---|
|
Prescribed Burning |
|
|
Prescribed Grazing |
Mechanism
Heavy disturbance including tillage and cropping; abandonment of cropland; seeding to improved pasture species; or installation of water control structures (terraces or dugouts) will transition any plant community in this ecological site to the Degraded State (3.0).
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.