Upland Loam (birchleaf mountain mahogany)
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Transition T2A More details
- Transition T3A More details
-
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
The Reference State is a description of this ecological site just prior to Euro-American settlement but long after the arrival of Native Americans. The description of the Reference State was determined by NRCS Soil Survey Type Site Location information and familiarity with rangeland relict areas where they exist. The least modified plant community would have been a tall shrub-dominated community with occasional Rocky Mountain juniper (Juniperus scopulorum), and a rich and productive understory of graminoids and forbs (1.1). Dominant shrubs would have included alderleaf mountain mahogany (Cercocarpus montanus), Utah serviceberry (Amelanchier utahensis), along with the associated shrubs mountain big sagebrush (Artemisia tridentata ssp. vaseyana), mountain snowberry (Symphoricarpos oreophilus), and antelope bitterbrush (Purshia tridentata). Primary grasses would have included bluebunch wheatgrass (Pseudoroegneria spicata), sheep fescue (Festuca ovina), mountain brome (Bromus marginatus), and Columbia needlegrass (Achnatherum nelsonii). Dominant forbs would have included arrowleaf balsamroot (Balsamorhiza sagittata), tailcup lupine (Lupinus caudatus ssp. caudatus), and longleaf phlox (Phlox longifolia) among others. A more complete list of species by lifeform for the Reference State is available in accompanying tables in the “Plant Community Composition by Weight and Percentage” section of this document. Wildfires would have maintained a balance between woody and non-woody vegetation, as many of the primary shrub species are root-sprouters and respond quickly following fire.
Submodel
Description
State 2 is a description of the ecological site shortly following Euro-American settlement, which has been influenced by the introduction of several non-native plants and animals, possible extinctions of native species, and a different climate. The plant community will be very similar to State 1 with the exception that some introduced species are likely to be present. This state can be regarded as the current potential. The site is dominated by a mixture of tall shrubs including alderleaf mountain mahogany, Utah serviceberry, mountain big sagebrush, mountain snowberry, antelope bitterbrush and scattered Rocky Mountain juniper. A rich and productive native perennial herbaceous understory will also be present (2.1). Because of the steepness of these sites, the vegetation was not heavily used by cattle and horses. However, herding of sheep was quite prevalent during the first half of the 20th Century. This vegetation was and still remains a favorite of big game. Because these classes of animals focus on browse, the understory is more intact than less steep nearby sites. Wildfires are important in rejuvenating the woody component, as the majority of the shrubs on these sites respond and recover rapidly following fire. Because soils on this site are rocky, they are considered “self armoring,” thus making the site resistant to the effects of erosion. Another factor contributing to the resiliency of this state is that the most desirable species are long-lived and are root-sprouters. Resiliency, however, will be reduced by excessive utilization which results in insufficient regeneration of the desirable species. Without regeneration of desirable species, some populations over-mature making them susceptible to catastrophic, sudden losses, and as a result unpalatable invaders can take over the site.
Submodel
Description
Lengthening of the fire cycle directly through fire control and indirectly through heavy livestock grazing reduces the fine fuels, ultimately tipping the balance toward woody plants and increasing the proportion of non-sprouters such as Rocky Mountain juniper and mountain big sagebrush (3.1). Because soils on this site are rocky they are considered “self armoring,” thus making the site resistant to the effects of erosion. The state will maintain stability with cool season fires, whereas hot summer fires are likely to reduce state stability.
Submodel
Description
State 4 is dominated by shorter, mostly re-sprouting shrubs, and an herbaceous understory composed of both native and introduced perennials. Native shrubs include mountain big sagebrush and yellow rabbitbrush (Chrysothamnus viscidiflorus). Wildfire or prescribed burning followed by a period of grazing deferment will provide a balance between woody and non-woody plants. If increased grazing is allowed too soon after fire, introduced species may dominate the understory (4.1). This state will lose stability with the increase in exotics and the loss of native herbs and grasses.
Submodel
Mechanism
The simultaneous introduction of exotic species, both plants and animals, possible extinctions of native flora and fauna, and climate change has caused State 1 to transition to State 2. Reversal of such historic changes (i.e. a return pathway) back to State 1 is not practical.
Mechanism
Heavy utilization primarily by sheep and occasionally by cattle and horses during the first half of the 20th century, combined with fire suppression, reduced much of the understory and allowed the shrubs to take over the site. Big game then hedged and high-lined the remaining shrubs. The survivors are all taller with the canopies having a marked browse line.
Mechanism
Prescribed burning or wildfire accompanied by aerial seeding, followed by grazing deferment, offers the only logical way to proactively promote a more diverse state with a better balance between woody and non-woody plants. Shrubs will be shorter, with non-sprouting species temporarily be reduced. Fire may potentially produce an increase in invasive herbs. If increased grazing is allowed too soon after fire, introduced species are given an additional advantage. A key indicator of the approach to this transition is the build up of fuels, and fire is the trigger for the transition. Because of steep slopes on this site, a restoration pathway is impracticable.
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.