Natural Resources
Conservation Service
Ecological site R030XB194CA
Rarely Flooded Alluvial Fan/Fan Apron
Last updated: 2/25/2025
Accessed: 08/19/2026
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Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Ecological site concept
This ecological site is found on alluvial fans and fan aprons. It occurs at elevations of 3200 to 4200 feet. Slopes range from 2 to 8 percent. Very rare to occasional flooding and no ponding occur on this site. Runoff is very low to low.
Please refer to group concept R030XB192CA to view the provisional STM.Table 1. Dominant plant species
Tree Not specified
Shrub (1) Senna armata
(2) Larrea tridentataHerbaceous (1) Pleuraphis rigida
Physiographic features
This ecological site is found on alluvial fans and fan aprons. It occurs at elevations of 3200 to 4200 feet. Slopes range from 2 to 8 percent. Very rare to occasional flooding and no ponding occur on this site. Runoff is very low to low.
Table 2. Representative physiographic features
Landforms (1) Alluvial fan
(2) Fan apron
Flooding duration Extremely brief (0.1 to 4 hours) to very brief (4 to 48 hours) Flooding frequency Very rare to occasional Elevation 3200 – 4200 ft Slope 4 – 15 % Water table depth 60 – 0 in Aspect Aspect is not a significant factor Climatic features
">Influencing water features
Soil features
This ecological site is found on the following map units and soil series:
4245 Yander, 20
PF900, Hypoint, 2
Data below may be wrong, based on Morongo soils, which this ESD is not linked to.
Table 3. Representative soil features
Surface texture (1) Sand
Family particle size (1) Sandy
Drainage class Somewhat excessively drained Permeability class Rapid Soil depth 40 – 60 in Surface fragment cover <=3" 65 – 100 % Surface fragment cover >3" 0 – 5 % Available water capacity
(0-40in)1.5 – 3.25 in Calcium carbonate equivalent
(0-40in)0 – 1 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 4 Soil reaction (1:1 water)
(0-40in)6 – 6.8 Subsurface fragment volume <=3"
(Depth not specified)5 – 25 % Subsurface fragment volume >3"
(Depth not specified)0 – 5 % Ecological dynamics
Please refer to group concept R030XB192CA to view the provisional STM.
State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Current Managed StateCommunity 1.1
Current Managed State
Vegetation Canopy Cover:
Shrubs:
blackbrush (Coleogyne ramosissima) 0-1%
Wiggins' cholla (Cylindropuntia echinocarpa) 0-1%
Nevada jointfir (Ephedra nevadensis) 1-5%
Eastern Mojave buckwheat (Eriogonum fasciculatum) 0-1%
narrowleaf goldenbush (Ericameria linearifolia) 0-1%
burrobrush (Hymenoclea salsola) 1-2%
white ratany (Krameria grayi) 0-1%
creosote bush (Larrea tridentata) 5-15%
Mexican bladdersage (Salazaria mexicana) 1-2%
desertsenna (Senna armata) 5-15%
jojoba (Simmondsia chinensis) 0-1%
turpentinebroom (Thamnosma montana) 0-1%
Mojave woodyaster (Xylorhiza tortifolia) 0-1%
Joshua tree (Yucca brevifolia) 0-1%
Mojave yucca (Yucca schidigera) 0-1%
Grasses:
red brome (Bromus rubens) 3-5%
big galleta (Pleuraphis rigida) 5-10%
Forbs:
bristly fiddleneck (Amsinckia tessellata) 3-5%
pincushion flower (Chaenactis fremontii) 1-3%
redstem stork's bill (Erodium cicutarium) 1-3%
Great Basin langloisia (Langloisia setosissima) 1-2%
desert dandelion (Malacothrix glabrata) 1-2%
small wirelettus (Stephanomeria exigua) 1-2%
Figure 1. Annual production by plant type (representative values) or group (midpoint values)
Table 4. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Shrub/Vine 105 160 210 Forb 50 110 170 Grass/Grasslike 30 50 75 Total 185 320 455 Table 5. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 20-30% Grass/grasslike foliar cover 10-10% Forb foliar cover 10-20% Non-vascular plants 0% Biological crusts 0% Litter 10-20% Surface fragments >0.25" and <=3" 30-40% Surface fragments >3" 0-0% Bedrock 0% Water 0% Bare ground 20-30% Table 6. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 0-1% 3-5% 5-15% >0.5 <= 1 – 1-5% 5-10% 5-10% >1 <= 2 – 20-30% – – >2 <= 4.5 – 0-1% – – >4.5 <= 13 – – – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Additional community tables
Table 7. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Shrub/Vine1 Shrubs 105–210 desertsenna SEAR8 Senna armata 75–125 – creosote bush LATR2 Larrea tridentata 15–40 – narrowleaf goldenbush ERLI6 Ericameria linearifolia 3–7 – burrobrush HYSA Hymenoclea salsola 3–7 – Nevada jointfir EPNE Ephedra nevadensis 3–7 – Mojave yucca YUSC2 Yucca schidigera 3–7 – Mexican bladdersage SAME Salazaria mexicana 1–5 – white ratany KRGR Krameria grayi 1–3 – turpentinebroom THMO Thamnosma montana 1–3 – Mojave woodyaster XYTO2 Xylorhiza tortifolia 0–2 – Joshua tree YUBR Yucca brevifolia 0–2 – jojoba SICH Simmondsia chinensis 0–2 – Eastern Mojave buckwheat ERFA2 Eriogonum fasciculatum 0–2 – blackbrush CORA Coleogyne ramosissima 0–1 – Wiggins' cholla CYEC3 Cylindropuntia echinocarpa 0–1 – Grass/Grasslike2 Grasses 30–75 red brome BRRU2 Bromus rubens 15–35 – big galleta PLRI3 Pleuraphis rigida 15–35 – Forb3 Forbs 50–170 redstem stork's bill ERCI6 Erodium cicutarium 20–60 – pincushion flower CHFR Chaenactis fremontii 15–35 – Forb, annual 2FA Forb, annual 1–20 – bristly fiddleneck AMTE3 Amsinckia tessellata 0–20 – smooth desertdandelion MAGL3 Malacothrix glabrata 10–20 – Great Basin langloisia LASE3 Langloisia setosissima 3–7 – small wirelettuce STEX Stephanomeria exigua 1–5 – Interpretations
Supporting information
Contributors
Allison Tokunaga
Approval
Sarah Quistberg, 2/25/2025
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
Author(s)/participant(s) Contact for lead author Date 08/19/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
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Perennial plant reproductive capability:
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