Loamy
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition 1A More details
- Transition 1B More details
- Transition 8A More details
- Restoration pathway 2A More details
- Transition 2A More details
- Transition 2B More details
- Transition 8A More details
- Restoration pathway 3A More details
- Transition 3A More details
- Transition 8A More details
- Transition 8A More details
- Transition 5A More details
- Transition 8A More details
- Transition 8A 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
This State represents what is believed to show the natural range of variability that dominated the dynamics of the ecological site prior to European settlement. This site in Reference, is dominated by cool-season grasses and sub-dominant warm-season grass. Grazing and the lack of grazing, fire and drought are the major drivers between plant communities. Depending on the season of use, continuous seasonal grazing can push this plant community to either a warm-season dominated or a cool-season dominated grassland. Non-use and no fire will result in heavy litter accumulations and the invasion of non-native cool-season grasses.
Submodel
Description
The Shortgrass State is dominated by shortgrass species and upland sedges. The State is the result of grazing patterns that did not provide adequate recover time for cool-season wheat and needle grasses. The hydrologic function of this site is dramatically altered. Runoff is high and infiltration is low. This State is very resistant to change through grazing management alone.
Submodel
Description
This state is the result of very heavy, concentrated disturbance such as concentrated rodent activity, or livestock concentration areas. This State can also develop as a result of invasion by highly competitive weed species such as Canada thistle, hound’s tongue, leafy spurge, or knapweeds. Extended periods of drought accompanied by heavy grazing can also push an ‘At Risk’ plant community phase to this state. In most cases, this phase is dominated by pioneer perennial and annual grass and forb species. Bare ground is also much higher than on any other plant community phase.
Submodel
Description
The forage production potential of a shortgrass plant community can be quickly improved through mechanical renovation. Mechanical renovation creates microrelief that can restore, hydrologic function by increasing infiltration and decreasing runoff. These factors favor cool-season species such as western wheatgrass, green needlegrass, and a variety of forbs. With proper management after renovation, this plant community will have similar plant composition and growth curve characteristics of the Reference State (1.0). Production could be higher, depending on the degree of mechanical alteration. Proper grazing management must be implemented to maintain this plant community.
Submodel
Description
This State has been invaded by Kentucky bluegrass and/or smooth brome but not at the levels where the plant community is dominated by these species. This State is ‘At Risk’ of transitioning to the Invaded State (6.0) which is dominated by smooth brome and/or Kentucky bluegrass.
Submodel
Description
This state is the result of invasion and dominance of introduced species. This state is characterized by the dominance of Kentucky bluegrass and smooth brome, and an increasing thatch layer that effectively blocks introduction of other plants into the system. Plant litter accumulation tends to favor the more shade tolerant introduced grass species. The nutrient cycle is also impaired, the result is typically a higher level of nitrogen which also favors the introduced species. Increasing plant litter decreases the amount of sunlight reaching plant crowns thereby shifting competitive advantage to shade tolerant, introduced grass species. Studies indicate that soil biological activity is altered, and this shift apparently exploits the soil microclimate and encourages growth of the introduced grass species. Once the threshold is crossed, a change in grazing management alone cannot cause a reduction in the invasive grass dominance. Preliminary studies would tend to indicate this threshold may exist when Kentucky bluegrass exceeds 30 percent of the plant community and native grasses represent less than 40 percent of the plant community composition. Plant communities dominated by Kentucky bluegrass have significantly less cover and diversity of native grasses and forb species (Toledo, D. et al., 2014).
Submodel
Description
This State can be transition to from any Plant Community. The two separate vegetative Plant Communities are highly variable in nature. They are derived through different management scenarios, and are not related successionally. Infiltration, runoff, and soil erosion varies depending on the vegetation present on the site.
Submodel
Mechanism
Heavy continuous season-long grazing or heavy continuous seasonal grazing (grazing at the same time of year every year) will shift this plant community to the Shortgrass State (2.0). Drought can expedite this transition. Forage production, species diversity, and ground cover will decrease.
Mechanism
Invasion of non-native cool-season grasses, no use and no fire and long-term light stocking will cause the Reference Plant Communities to transition to a Native/Invaded State (5.0). Forage production may not change however species diversity will become smaller and litter will increase.
Mechanism
Heavy disturbance including tillage, abandoned cropland or seeding to improved pasture species result in a transition to the Disturbed State (7.0).
Mechanism
Long-term prescribed grazing may potentially convert the plant community to the Western Wheatgrass-Blue Grama-Buffalograss Plant Community (1.2), assuming an adequate seed/vegetative source is present. This could require significant time and input to achieve and in the end may not meet management objectives.
Mechanism
Heavy continuous season-long grazing and/or frequent severe defoliation will likely move this plant community to the Early Seral State (3.0).
Mechanism
Mechanical renovation such as pitting, light disking, chiseling and possible inter-seeding in combination with long-term prescribed grazing will help improve the productivity of the site. This pathway will convert the plant community to the Renovated State (4.0).
Mechanism
Heavy disturbance including tillage, abandoned cropland or seeding to improved pasture species result in a transition to the Disturbed State (7.0).
Mechanism
After removing the disturbance that created the Early Seral State (3.0) and long-term prescribed grazing, including adequate rest periods, and normal precipitation patterns this plant community will transition back to the Shortgrass State (2.0) and possible through the successional stages eventually leading to the Western Wheatgrass-Blue Grama-Buffalograss Plant Community (1.2). Depending on the slope, aspect, and size, and if adequate perennial plants exist, this change can occur more rapidly but typically it will take an extended period of time and may not meet management objectives.
Mechanism
If this plant community is invaded by non-native cool-season grasses and the disturbance causing the frequent defoliation is removed this plant community is likely to transition to the Invaded State (6.0).
Mechanism
Heavy disturbance including tillage, abandoned cropland or seeding to improved pasture species result in a transition to the Disturbed State (7.0).
Mechanism
Heavy disturbance including tillage, abandoned cropland or seeding to improved pasture species result in a transition to the Disturbed State (7.0).
Mechanism
Heavy continuous season-long grazing, or no use and no fire, or long-term light grazing will cause a transition of the Native/Invaded State to the Invaded State (6.0). The ecological threshold can be identified by the percentage of non-native cool-season species in the Plant Community. Preliminary studies would tend to indicate this threshold may exist when Kentucky bluegrass exceeds 30 percent of the plant community and native grasses represent less than 40 percent of the plant community composition (Toledo, D. et al., 2014). Smooth brome is assumed to follow a similar ecological threshold but is not document scientifically.
Mechanism
Heavy disturbance including tillage, abandoned cropland or seeding to improved pasture species result in a transition to the Disturbed State (7.0).
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.