Coarse Loamy Very Deep Fan Remnants
Scenario model
Current ecosystem state
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Management practices/drivers
Select a transition or restoration pathway
- Transition 1 More details
- Transition T2 More details
- Restoration pathway 1 More details
- Transition 3 More details
- Restoration pathway 2 More details
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No transition or restoration pathway between the selected states has been described
Target ecosystem state
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Description
State 1 represents the historic range of variability for this ecological site. This state no longer exists due to the ubiquitous naturalization of non-native species in the Mojave Desert. Periodic drought and rare fire were the natural disturbances influencing this ecological site. Fire would have been a very rare occurrence due to the lack of a continuous fine fuel layer (Minnich 2003, Webb et al. 1987).
Blackbrush is killed by moderate to severe fire, and the historic fire return interval is suggested to be upwards of 100 years (Webb et al. 1987, Brooks et al. 2007, Abella et al. 2009). With the absence of non-native species to fuel recurrent fires, this long fire-return interval allowed for recovery to pre-burn densities. Joshua tree suffers high mortality in response to fire (Minnich 2003; DeFalco et al. 2010), but the long historic fire return intervals allowed for recovery to pre-burn densities.
Data for this State does not exist, but it would have been similar to State 2, except with only native species present. See State 2 narrative for more detailed information.
Description
State 2 represents the current range of variability for this site. Non-native annuals, including red brome and red-stem stork’s bill (Erodium cicutarium) are naturalized in this plant community. Their abundance varies with precipitation, but they are at least sparsely present (as current year's growth or present in the soil seedbank).
Submodel
Description
This state is characterized by the loss of blackbrush from the plant community due to severe or recurrent fire.
Submodel
Description
This state develops when the fire return interval is 5 to 20 years. This state has been significantly altered from the natural range of variability found in States 1 through 3. Blackbrush and Joshua tree have been lost, and big galleta, non-native annual grasses, native sub-shrubs, and short-lived shrubs dominate the community. Annual grasses and forbs are abundant immediately post-fire, with dominance by big galleta, subshrubs and short-lived perennials several years post-fire.
Submodel
Mechanism
This transition occurred with the naturalization of non-native species in this ecological site. Non-native species were introduced with settlement of the Mojave Desert region in the 1860s. Post-settlement cattle and sheep grazing, as well as dryland farming, helped to spread and facilitate their establishment (Brooks and Pyke 2000, Brooks et al. 2007).
Mechanism
This transition occurs with extensive, severe fire when blackbrush seed sources are not available to colonize burned areas, or with recurrent fire in Community Phase 2.3.
Mechanism
Restoration of arid desert communities severely altered by repeat fire at the landscape scale is very difficult (Allen 1993). Reducing invasion of non-native grasses that increase after fire may help promote native plant recovery, and reduce the probability of repeat burning (Fuhrmann et al. 2009, Matchett et al. 2009, Steers and Allen 2010); however, accomplishing this at a landscape scale, for a time period long enough to be effective, has not yet been accomplished. In small-scale trials, Fusilade, a grass-specific herbicide, was successful in reducing invasive grasses in burned creosote bush communities in the Colorado Desert in the initial three years after fire (Steers and Allen 2010). The long-term efficacy of such treatments on a landscape scale, and non-target effects have not yet been determined. The pre-emergent herbicide Plateau was applied in conjunction with aerial seeding of natives after fire in Zion National Park (Fuhrmann et al. 2009, Matchett et al. 2009). Initial results indicate that autumn application of Plateau after fire is most effective for reducing cheatgrass (Bromus tectorum), but longer-term monitoring is needed to evaluate long-term and non-target effects. In addition to controlling invasive species, active recovery of native vegetation may be attempted. Methods may include seeding of early native colonizers such as desert globemallow, burrobrush, threeawns (Aristida spp.), and desert marigold (e.g. Abella et al. 2009, Abella et al. 2012). Increased native cover may help to reduce non-native plant invasion, helps to stabilize soils, provides a source of food and cover for wildlife, including desert tortoise (Gopherus agassizii), and provides microsites that facilitate blackbrush establishment. However, the amount of seed required for success is often prohibitive. Large-scale planting of both early colonizers and community dominants tends to be more successful in terms of plant survival, especially if outplants receive supplemental watering during the first two years (Allen 1993). Joshua tree is readily cultivated for outplanting, but blackbrush is difficult to cultivate for outplanting due to susceptibility to fungal pathogens in the greenhouse environment.
Mechanism
This transition occurs when the fire return interval in State 3 is less than 20 years.
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.