Loamy (Lo) Dry Shrubland
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
-
Transition T1A
prolonged drought, improper grazing, or a combination of these factors
More details -
Transition T1B
introduction of non-native invasive species (crested wheatgrass, noxious weeds, etc.)
More details -
Transition T1C
conversion to cropland
More details -
Restoration pathway R2A
range seeding, grazing land mechanical treatment, timely moisture, proper grazing management (management intensive and costly)
More details -
Transition T2A
introduction of weedy species; combined with drought and/or improper grazing management
More details -
Transition T2B
conversion to cropland
More details -
Transition T3A
conversion to cropland
More details -
Transition T4A
cessation of annual cropping
More details -
Transition T5A
conversion to cropland
More details -
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference state contains three communities characterized by mid-statured, cool-season grasses and Wyoming big sagebrush, a perennial, evergreen, non-sprouting shrub. This state evolved under the combined influences of climate, grazing, and fire with climatic variation having the greatest influence on cover and production. In general, this state was resilient to grazing and fire, although these factors could influence species composition in localized areas. Lesser spikemoss, also known as dense clubmoss (Selaginella densa), is frequently present and may constitute significant ground cover. Its dynamics are not well understood (Romo, 2011), however, and its abundance varies greatly from site to site without a discernable reason.
Submodel
Description
The Shortgrass state consists of two communities. The dynamics of this state are driven by long-term drought, improper grazing management, or a combination of these factors. Blue grama increases with long-term improper grazing at the expense of cool-season mid-statured grasses (Coupland, 1961; Biondini and Manske, 1996; Derner and Whitman, 2009). Once established, blue grama-dominated communities can alter soil properties, creating conditions that resist the establishment of other grass species (Dormaar and Willms, 1990; Dormaar et al., 1994). Reductions in stocking rates can reduce blue grama cover and increase the cover of cool-season mid-statured grasses, although this recovery may take decades (Dormaar and Willms, 1990, Dormaar et al., 1994). Dense clubmoss may or may not be present in this state. Its density is highly variable and the dynamics of this species are not well understood. Cover of Wyoming big sagebrush varies depending on fire frequency, with dynamics similar to the Reference state.
Submodel
Description
The Invaded state occurs when invasive plant species invade adjacent native grassland communities. Crested wheatgrass is a common concern, especially when native plant communities are adjacent to seeded pastures. An estimated 20 million acres of crested wheatgrass have been planted in the western U.S. (Holechek, 1981). Crested wheatgrass produces abundant seeds that can dominate the seed bank of invaded grasslands (Henderson and Naeth, 2005), although crested wheatgrass cover decreases with increasing distance from seeded areas (Heidinga and Wilson, 2002). The early growth of crested wheatgrass allows this species to take advantage of early-season soil moisture, which may result in competitive exclusion of native cool-season rhizomatous wheatgrasses and bunchgrasses, such as needle and thread and prairie Junegrass (Christian and Wilson, 1999; Heidinga and Wilson, 2002; Henderson and Naeth, 2005). Reduced soil quality (Dormaar et al., 1995), reduced plant species diversity, and simplified structural complexity (Henderson and Naeth, 2005) result in a state that is substantially departed from the Reference state.
Other invasive species that could be a concern are annual bromes and noxious weeds. Annual bromes are generally not a significant concern in MLRA 52, however, in the Loamy Dry Shrubland, there could be instances where they do significantly affect the site. More information is needed to assess this condition. Noxious weeds such as leafy spurge are uncommon on this site, but they may also invade and displace native species. Although very aggressive, these species can sometimes be suppressed through intensive management (herbicide application, biological control, or intensive grazing management). Control efforts are unlikely to eliminate noxious weeds, but their density can be sufficiently suppressed so that species composition, structural complexity, and soil quality are similar to that of the Reference state. However, cessation of control methods will most likely result in recolonization of the site by the noxious species.
Submodel
Description
The Cropland state occurs when land is put into cultivation. Major crops in MLRA 52 include winter wheat, spring wheat, and barley.
Submodel
Description
The Post Cropland state occurs when cultivated cropland is abandoned and allowed to either re-vegetate naturally or is seeded back to perennial species for grazing or wildlife use. This state can transition back to the Cropland state if the site is put back into cultivation.
Submodel
Mechanism
Prolonged drought, improper grazing practices, or a combination of these factors weaken the resilience of the Reference state and drive its transition to the Shortgrass state. The Reference state transitions to the Shortgrass state when mid-statured graminoids become rare and contribute little to production. Shortgrasses such as blue grama, Sandberg bluegrass, and prairie Junegrass dominate the plant community.
Context dependence
Drought may accelerate or exacerbate change. Soils are particularly susceptible to erosion when dry.
Mechanism
The Reference state transitions to the Invaded state when aggressive perennial grasses or noxious weeds invade the Shortgrass state. Crested wheatgrass, in particular, is a concern when native plant communities are adjacent to seeded pastures. Exotic plant species dominate the site in terms of cover and production. Site resilience has been substantially reduced. In addition, other rangeland health attributes, such as the reproductive capacity of native grasses (Henderson and Naeth, 2005) and soil quality (Smoliak and Dormaar, 1985; Dormaar et al., 1995), have been substantially altered from the Reference state.
Context dependence
Close proximity to a seed source increases likelihood of encroachment by invasive species.
Mechanism
Tillage or application of herbicide followed by seeding of cultivated crops, such as winter wheat, spring wheat, and barley, transitions the Reference state to the Cropland state.
Context dependence
Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Mechanism
Blue grama can resist displacement by other species (Dormaar and Willms, 1990; Laycock, 1991; Dormaar et al., 1994; Lacey et al., 1995). A reduction in livestock grazing pressure alone may not be sufficient to reduce the cover of blue grama in the Shortgrass state (Dormaar and Willms, 1990) and mechanical treatments may be necessary (Hart et al., 1985). Therefore, returning the Shortgrass state to the Reference state can require considerable cost, energy, and time.
Context dependence
Drought may inhibit recovery despite management inputs. Reseedings are more likely to fail during drought.
Mechanism
The Shortgrass state transitions to the Invaded state when aggressive perennial grasses, noxious weeds, and other invasive plants invade the Shortgrass state. Exotic plant species dominate the site in terms of cover and production. Site resilience has been substantially reduced.
Context dependence
Close proximity to a seed source increases likelihood of encroachment by invasive species.
Mechanism
Tillage or application of herbicide followed by seeding of cultivated crops, such as winter wheat, spring wheat, and barley, transitions the Shortgrass state to the Cropland state.
Context dependence
Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Mechanism
The Invaded state will transition to the Cropland state when the site is placed under cultivation.
Context dependence
Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Mechanism
The transition from the Cropland state to the Post Cropland state occurs with the cessation of cultivation. The site may also be seeded to perennial forage species, such as crested wheatgrass and alfalfa, or a mix of native species.
Context dependence
Drought may inhibit recovery despite management inputs. Reseedings are more likely to fail during drought.
Mechanism
Tillage or application of herbicide followed by seeding of cultivated crops, such as winter wheat, spring wheat, and barley, transitions the Post Cropland state to the Cropland state.
Context dependence
Drought may accelerate or exacerbate change. Cropped soils are particularly susceptible to erosion during drought.
Model keys
Briefcase
Add ecological sites and Major Land Resource Areas to your briefcase by clicking on the briefcase (
) icon wherever it occurs. Drag and drop items to reorder. Cookies are used to store briefcase items between browsing sessions. Because of this, the number of items that can be added to your briefcase is limited, and briefcase items added on one device and browser cannot be accessed from another device or browser. Users who do not wish to place cookies on their devices should not use the briefcase tool. Briefcase cookies serve no other purpose than described here and are deleted whenever browsing history is cleared.
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.