Mountain Stony Loam (quaking aspen thicket)
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
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Transition T1
introduction of exotic species
More details -
Transition T2
The lack of fire and continued season-long grazing
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Restoration pathway R3
With prescribed or wildfire, followed by a reduction in livestock grazing levels
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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 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. Along the lee sides of ridges in areas where snow accumulates, these linear-shaped copses would have been dominated by quaking aspen (Populus tremuloides), with a scattering of low shrubs, and a rich and productive native perennial herbaceous understory. Mountain snowberry (Symphoricarpos oreophilus), chokecherry (Prunus virginiana), and Woods’ rose (Rosa woodsii), among others would have been common shrub associates. The major grasses/grass-likes would have been Mountain brome (Bromus marginatus), slender wheatgrass (Elymus trachycaulus), and Ross’ sedge (Carex rossii). Forbs would have included a mixture of Fendler's meadow-rue (Thalictrum fendleri), Gray's biscuitroot (Lomatium grayi), and lambstongue ragwort (Senecio integerrimus) (1.1). These sites would have typically had fire return intervals every 80-100 years.
Submodel
Description
State 2 is identical to State 1 in form and function, with the exception of the presence of non-native plants and animals, possible extinctions of native species, and a different climate. State 2 is a description of the ecological site shortly following Euro-American settlement. This state can be regarded as the current potential. The site is dominated by a shrubby form of quaking aspen along with a suite of mountain shrub species such as mountain snowberry, chokecherry, and woods’ rose. The native perennial herbaceous understory species include grasses and grass-likes such as Mountain brome, slender wheatgrass, and Ross’ sedge, and forbs including Fendler's meadow-rue, Gray's biscuitroot, lambstongue, ragwort, and hound’s tongue (Cynoglossum spp.), among others (2.1). Some non-native species may be present. Since this ESD usually occurs on sheltered topography (e.g. in lee of ridges with extra snowdrift, hollows, north slopes), it is more productive and responsive to management than other sites in this zone. It is however, very important to mule-deer fawning and neo-tropical migrant birds. This State is maintained by periodic wildfire and by a healthy, productive, and diverse plant community that can provide native seed sources and promotes soil stability, water infiltration, and soil moisture retention. Periodic cool season (spring or fall) prescribed fire may also serve to maintain the balance between woody and herbaceous species in these sites. These sites tend to be particularly resilient due to their location in mesic (moist) micro-sites that are usually covered by snow for about half of the year. The resiliency of this State can be maintained by reducing livestock and big game use and by occasional fire. Conversely, excessive livestock and big game use and fire suppression will negatively impact the resiliency of this state.
Submodel
Description
In the absence of fire, and with continued heavy impacts from livestock grazing, the native herbaceous understory will markedly decrease. Fire exclusion promotes the thickening of the aspen and other woody species at the expense of the herbaceous understory. The stability of this State is maintained by lack of wildfire and continued impacts to the herbaceous species by livestock.
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
The lack of fire and continued season-long grazing during the growing season of grasses throughout the 1860s to the 1950s caused many of these sites to transition into a Thickened Aspen Thicket/ Diminished Herbaceous Understory State. The approach to this transition is indicated by a decrease in the most desirable forage species and an increase in less desirable species. This transition is triggered by sustained heavy grazing and by fire exclusion occurring since Euro-American settlement.
Mechanism
With prescribed or wildfire, followed by a reduction in livestock grazing levels, it may be possible to restore the aspen and some of the more desirable forage species, as aspen will readily re-sprout following fire. However, retreatment may be required every 40 to 50 years to maintain the appropriate balance of woody and herbaceous components.
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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.