Natural Resources
Conservation Service
Ecological site R030XB218AZ
Sandy Wash 6-9" p.z.
Last updated: 10/21/2024
Accessed: 12/22/2024
General information
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.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
MLRA notes
Major Land Resource Area (MLRA): 030X–Mojave Basin and Range
This unit occurs within the Basin and Range Province and is characterized by broad basins, valleys, and old lakebeds. Widely spaced mountains trending north to south occur throughout the area. Isolated, short mountain ranges are separated by an aggraded desert plain. The mountains are fault blocks that have been tilted up. Long alluvial fans coalesce with dry lakebeds between some of the ranges.
LRU notes
AZ LRU 30-2 – Middle Mohave Desert
Elevations range from 1500 to 3200 feet and precipitation averages 6 to 9 inches per year. Vegetation includes creosotebush, white bursage, yucca, prickly pear and cholla species, Mormon tea, flattop buckwheat, ratany, winterfat, bush muhly, threeawns, and big galleta. The soil temperature regime is thermic and the soil moisture regime is typic aridic.
Ecological site concept
This ecological site is located in bottoms. Soils are gravelly sandy loams braided with watercourses of riverwash.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Hymenoclea salsola |
| Herbaceous |
(1) Pleuraphis rigida |
Physiographic features
This ecological site occurs in and along the edges of ephemeral streams or washes. It is often intricately intertwined with, but is not, the riverwash. It occasionially receives additional run-in moisture from the surrounding ecological sites. The soil is very sandy and is often gravelly and/or cobbly as well.
Table 2. Representative physiographic features
| Landforms |
(1)
Alluvial fan
(2) Flood plain |
|---|---|
| Flooding duration | Very brief (4 to 48 hours) |
| Flooding frequency | Occasional |
| Ponding frequency | None |
| Elevation | 1,500 – 3,000 ft |
| Slope | 1 – 5% |
| Aspect | Aspect is not a significant factor |
Climatic features
The climate is arid and warm. Annual precipitation ranges from 6 to 9 inches. About 65 percent of the rainfall comes from October through May as gentle rain from Pacific storms which may last for a couple of days. The rest of the rainfall comes during the summer monsoon season from July through September as spotty, brief, intense thunderstorms. Snow rarely falls, and only remains on the ground a few hours at most. Annual air temperature ranges from 59 to 70 degrees F. The average frost-free period ranges from 156 to 259 days.
Table 3. Representative climatic features
| Frost-free period (average) | 259 days |
|---|---|
| Freeze-free period (average) | 290 days |
| Precipitation total (average) | 9 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soil of this ecological site is deep to very deep. Surface textures range from loamy sand to sandy loam and is often gravelly or very gravelly. Subsurface textures range from sand to sandy loam and generally gravelly to extremely gravelly or very cobbly.
A typical profile of this soil is:
A—0 to 1 inch; gravelly sandy loam
C1—1 to 9 inches; loamy coarse sand
C2—9 to 60 inches; extremely gravelly loamy
coarse sand
The taxonomic classification of this soil is Sandy, mixed thermic Typic Torrifluvents.
Soils correlated to this ecological site include map unit 623005, Arizo, Shivwits SSA; 697006, Arizo and Franconia, 697007, Arizo, Central Mohave County SSA.
Table 4. Representative soil features
| Surface texture |
(1) Gravelly sandy loam (2) Very cobbly sandy loam (3) Very gravelly loamy sand |
|---|---|
| Family particle size |
(1) Sandy |
| Drainage class | Excessively drained |
| Permeability class | Moderately rapid to very rapid |
| Soil depth | 60 in |
| Surface fragment cover <=3" | 10 – 50% |
| Surface fragment cover >3" | 35% |
| Available water capacity (0-40in) |
1.2 – 1.5 in |
| Calcium carbonate equivalent (0-40in) |
6 – 10% |
| Electrical conductivity (0-40in) |
2 mmhos/cm |
| Soil reaction (1:1 water) (0-40in) |
7.9 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
25 – 65% |
| Subsurface fragment volume >3" (Depth not specified) |
35% |
Ecological dynamics
Sandy Wash, 6"-9" p.z., is a shrub dominated ecological site. Sparse perennial grasses and forbs are occasionally encountered. Annual forbs and grasses flourish following rainfall. Other than frequent flash flooding, natural disturbances are rare. After introduction of non-native annuals (forbs and/or grasses), they persist on this site. Dominant shrubs are creosote and hymenochlea. Assorted half-shrubs are widely scattered.
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 text
State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Historic Native
Community 1.1
Historic Native Plant Community
The dominant aspect of this site is a desert shrub. This site is dominated by catclaw acacia, white burrobrush, and creosotebush. Perennial grasses are present in minor amounts. The burrobrush on this site will increase if other plants decrease for any reason. Also, if plant cover is lost there will be an increase in channel depth and erosion.
Figure 4. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (lb/acre) |
Representative value (lb/acre) |
High (lb/acre) |
|---|---|---|---|
| Shrub/Vine | 109 | 263 | 381 |
| Grass/Grasslike | 8 | 33 | 67 |
| Forb | 8 | 25 | 44 |
| Tree | 0 | 4 | 8 |
| Total | 125 | 325 | 500 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 0-2% |
| Grass/grasslike foliar cover | 0-1% |
| Forb foliar cover | 0-1% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 0% |
| Surface fragments >0.25" and <=3" | 0% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 0% |
Table 7. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | – | – | 0-2% |
| >0.5 <= 1 | – | – | 0-2% | – |
| >1 <= 2 | – | – | – | – |
| >2 <= 4.5 | – | – | – | – |
| >4.5 <= 13 | – | 10-14% | – | – |
| >13 <= 40 | – | – | – | – |
| >40 <= 80 | – | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
Figure 5. Plant community growth curve (percent production by month). AZ3022, 30.2 6-9" p.z. upland sites. Growth begins in the late winter, most growth occurs in the spring..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 2 | 19 | 33 | 18 | 7 | 7 | 11 | 3 | 0 | 0 | 0 |
Figure 6. Plant community growth curve (percent production by month). AZ3030, 40-3AZ 7-10" p.z. big galleta. Growth begins in the spring, goes dormant in May through June, most growth occurs during the summer rainy season..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 10 | 10 | 0 | 0 | 15 | 55 | 10 | 0 | 0 | 0 |
State 2
Historic Native Plant Community plus Introduced Annuals
Community 2.1
Non-native Annuals
This plant community resembles the historic native plant community, but exotic annuals have been introduced. Non-native species include Asian mustard (Brassica tournefortii), red brome, Mediterranean grass (Schismus spp.), and filaree. The flourish of non-native annuals that occurs following rainfalls may preclude native annuals.
Transition T1A
State 1 to 2
Introduction of non-native annual forb and grass seed.
Additional community tables
Table 8. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | 3–16 | |||||
| big galleta | PLRI3 | Pleuraphis rigida | 3–16 | – | ||
| 2 | 0–3 | |||||
| threeawn | ARIST | Aristida | 0–3 | – | ||
| 3 | 0–6 | |||||
| sand dropseed | SPCR | Sporobolus cryptandrus | 0–6 | – | ||
| 4 | 0–6 | |||||
| slim tridens | TRMU | Tridens muticus | 0–6 | – | ||
| 5 | 3–16 | |||||
| Grass, annual | 2GA | Grass, annual | 3–16 | – | ||
|
Forb
|
||||||
| 6 | 3–10 | |||||
| desert globemallow | SPAM2 | Sphaeralcea ambigua | 3–10 | – | ||
| 7 | 3–16 | |||||
| Forb, annual | 2FA | Forb, annual | 3–16 | – | ||
| 8 | 3–10 | |||||
| Forb, perennial | 2FP | Forb, perennial | 3–10 | – | ||
|
Shrub/Vine
|
||||||
| 9 | 16–49 | |||||
| catclaw acacia | ACGR | Acacia greggii | 16–49 | – | ||
| 10 | 65–98 | |||||
| burrobrush | HYSA | Hymenoclea salsola | 65–98 | – | ||
| 11 | 32–64 | |||||
| creosote bush | LATR2 | Larrea tridentata | 32–64 | – | ||
| 12 | 3–16 | |||||
| water jacket | LYAN | Lycium andersonii | 3–16 | – | ||
| 13 | 0–6 | |||||
| burrobush | AMDU2 | Ambrosia dumosa | 0–6 | – | ||
| 14 | 3–16 | |||||
| Nevada jointfir | EPNE | Ephedra nevadensis | 3–16 | – | ||
| 15 | 3–10 | |||||
| Eastern Mojave buckwheat | ERFAP | Eriogonum fasciculatum var. polifolium | 3–10 | – | ||
| 16 | 0–6 | |||||
| woolly fruit bur ragweed | AMER | Ambrosia eriocentra | 0–6 | – | ||
| 17 | 0–6 | |||||
| purple sage | SADO4 | Salvia dorrii | 0–6 | – | ||
| 18 | 0–3 | |||||
| peach thorn | LYCO2 | Lycium cooperi | 0–3 | – | ||
| 19 | 0–3 | |||||
| brittlebush | ENFA | Encelia farinosa | 0–3 | – | ||
| 20 | 0–10 | |||||
| pricklypear | OPUNT | Opuntia | 0–10 | – | ||
| 21 | 0–6 | |||||
| rayless goldenhead | ACSP | Acamptopappus sphaerocephalus | 0–6 | – | ||
| 22 | 0–10 | |||||
| button brittlebush | ENFR | Encelia frutescens | 0–10 | – | ||
| 23 | 0–13 | |||||
| turpentinebroom | THMO | Thamnosma montana | 0–13 | – | ||
| 24 | 0–10 | |||||
| Mexican bladdersage | SAME | Salazaria mexicana | 0–10 | – | ||
| 25 | 0–3 | |||||
| desert almond | PRFA | Prunus fasciculata | 0–3 | – | ||
| 26 | 3–16 | |||||
| Shrub (>.5m) | 2SHRUB | Shrub (>.5m) | 3–16 | – | ||
|
Tree
|
||||||
| 27 | 0–6 | |||||
| Joshua tree | YUBR | Yucca brevifolia | 0–6 | – | ||
Interpretations
Animal community
Wildlife Species List:
Snakes, Lizards, Ground Squirrels, Blacktail Jackrabbit, Cottontail Rabbit
Supporting information
Type locality
| Location 1: Mohave County, AZ | |
|---|---|
| Township/Range/Section | T27 N. R20 W. S20 |
| Latitude | 35° 43′ 30″ |
| Longitude | 114° 27′ 30″ |
| General legal description | Mt. Tipton 3NW Quad - Sec. 20, T. 27 N., R. 20 W.; Lat. 35 43' 30", Long. 114 27' 30"; Mohave County, Arizona. |
| Location 2: Mohave County, AZ | |
| Township/Range/Section | T36 N. R16 W. S35 |
| General legal description | Pakoon Wash on Pakoon Springs Ranch; Sec. 35, T. 36 N., R. 16 W.; Mohave County, Arizona. |
Contributors
Harmon Hodgkinson
Harmon S. Hodgkinson
Larry D. Ellicott
Stephen Cassady
Approval
Kendra Moseley, 10/21/2024
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 | 10/22/2024 |
| Approved by | Kendra Moseley |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
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:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
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:
-
Perennial plant reproductive capability:
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