Natural Resources
Conservation Service
Ecological site R030XC333AZ
Basalt Hills 10-13" p.z. Limy
Accessed: 04/25/2024
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
AZ CRA 30.3 – Upper Mohave Desert
Elevations range from 2800 to 4500 feet and precipitation averages 9 to 12 inches per year. Vegetation includes Joshua tree, blackbrush, creosotebush, ratany, bush muhly, big galleta, black grama, desert needlegrass, and Indian ricegrass. The soil temperature regime is thermic and the soil moisture regime is typic aridic. 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.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Eriogonum fasciculatum |
| Herbaceous |
Not specified |
Physiographic features
This ecological site occurs in an upland positon on shoulders and backslopes of mountains and hills.
Table 2. Representative physiographic features
| Landforms |
(1)
Mountain
(2) Hill |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,800 – 4,500 ft |
| Slope | 15 – 70% |
| Aspect | Aspect is not a significant factor |
Climatic features
The climate is arid and warm. Annual precipitation ranges from 10 to 13 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 46 to 76 degrees F. The average frost-free period ranges from 121 to 231 days.
Table 3. Representative climatic features
| Frost-free period (average) | 231 days |
|---|---|
| Freeze-free period (average) | 269 days |
| Precipitation total (average) | 13 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 shallow with surface textures of extremely cobblly loam and extremely stony loam. Subsoil textures are extremely gravelly loam. Soil parent materials are alluvium and colluvium from basalt. Soil available water capacity is very low. The soil's erosion hazard by water is severe and by wind is slight. Runoff from this soil is slow. The soil is non-saline, non-sodic with pH of 8.0 (moderately alkaline). The soil moisture regime is typic aridic and temperature regime is thermic.
Depth to basalt bedrock is about 15 inches. Rock outcrop is associated with the site.
A typical soil profile is:
A-0 to 2 inches; very stony loam
Bk-2 to 15 inches; very gravelly loam
2R- 15 inches; unweathered bedrock
Taxonomic classifications of soils correlated to this ecological site include Loamy-skeletal, mixed, superactive, calcareous, thermic Lithic Torriorthents; Loamy-skeletal, mixed, superactive, thermic Typic Haplocalcids.
Map units correlated to this ecological site include 627093, 627095, 627136, Razorback and Nickel family soils, Mohave County, AZ, Southern Part SSA.
Table 4. Representative soil features
| Parent material |
(1)
Alluvium
–
basalt
|
|---|---|
| Surface texture |
(1) Extremely cobbly loam (2) Extremely stony loam |
| Family particle size |
(1) Loamy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderate |
| Soil depth | 10 – 20 in |
| Surface fragment cover <=3" | 45 – 65% |
| Surface fragment cover >3" | 40 – 65% |
| Available water capacity (0-40in) |
0.5 – 1 in |
| Calcium carbonate equivalent (0-40in) |
2 – 10% |
| Electrical conductivity (0-40in) |
Not specified |
| Sodium adsorption ratio (0-40in) |
Not specified |
| Soil reaction (1:1 water) (0-40in) |
7.4 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
70 – 80% |
| Subsurface fragment volume >3" (Depth not specified) |
10% |
Ecological dynamics
The historic climax plant community (HCPC) for a site in North America is the plant community that existed at the time of European immigration and settlement. It is the plant community that was best adapted to the unique combination of environmental factors associated with the site. The historic climax plant community was in dynamic equilibrium with its environment. It is the plant community that was able to avoid displacement by the suite of disturbances and disturbance patterns (magnitude and frequency) that naturally occurred within the area occupied by the site. Natural disturbances, such as drought, fire, grazing by native fauna, and insects, were inherent in the development and maintenance of these plant communities. The effects of these disturbances are part of the range of characteristics of the site that contribute to that dynamic equilibrium. Fluctuations in plant community structure and function caused by the effects of these natural disturbances establish the boundaries of dynamic equilibrium. They are accounted for as part of the range of characteristics for an ecological site. Some sites may have a small range of variation, while others have a large range.
The historic climax plant community of an ecological site is not a precise assemblage of species for which the proportions are the same from place to place or from year to year. In all plant communities, variability is apparent in productivity and occurrence of individual species. Spatial boundaries of the communities; however, can be recognized by characteristic patterns of species composition, association, and community structure. The HCPC for this ecological site has been estimated by sampling relict or relatively undisturbed sites and/or reviewing historic records.
Plant communities that are subjected to abnormal disturbances and physical site deterioration or that are protected from natural influences, such as fire and grazing, for long periods seldom typify the historic climax plant community. The physical site deterioration caused by the abnormal disturbance results in the crossing of a threshold or irreversible boundary to another state, or equilibrium, for the ecological site. There may be multiple thresholds and states possible for an ecological site, determined by the type and or severity of abnormal disturbance. The known states and transition pathways for this ecological site are described in the accompanying state and transition model.
The Plant Community Plant Species Composition table provides a list of species and each species or group of species’ annual production in pounds per acre (air-dry weight) expected in a normal rainfall year. Low and high production yields represent the modal range of variability for that species or group of species across the extent of the ecological site.
The Annual Production by Plant Type table provides the median air-dry production and the fluctuations to be expected during favorable, normal, and unfavorable years.
The present plant community on an ecological site can be compared to the various common vegetation states that can exist on the site. The degree of similarity is expressed through a similarity index. To determine the similarity index, compare the production of each species to that shown in the plant community description. For each species, count no more than the maximum amount shown for the species, and for each group, count no more than the maximum shown for the group. Divide the resulting total by the total representative value shown in the Annual Production by Plant Type table for the reference plant community. Variations in production due to above or below normal rainfall, incomplete growing season or utilization must be corrected before comparing it to the site description. The Worksheet for Determining Similarity Index is useful in making these corrections. The accompanying growth curve can be used as a guide for estimating percent of growth completed.
State and transition model
More interactive model formats are also available.
View Interactive Models
More interactive model formats are also available.
View Interactive Models
Click on state and transition labels to scroll to the respective text
Ecosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant Community
Community 1.1
Historic Climax Plant Community
The dominant aspect of this plant community is a desert shrub with grasses and forbs. Major shrubs include flattop buckwheat, range ratany, white bursage, creosotebush and, in some areas, blackbrush. Big galleta and desert needlegrass are the dominant grasses. Forbs are present usually in minor amounts. Most of the site is difficult to graze due to loose rock material on the soil surface and steep slopes.
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 | 67 | 188 | 479 |
| Grass/Grasslike | 22 | 75 | 205 |
| Forb | 11 | 35 | 102 |
| Tree | 0 | 2 | 14 |
| Total | 100 | 300 | 800 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 1-3% |
| Grass/grasslike foliar cover | 0-2% |
| Forb foliar cover | 0% |
| 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 | – | – | 2-4% | – |
| >1 <= 2 | – | – | – | – |
| >2 <= 4.5 | – | 9-11% | – | – |
| >4.5 <= 13 | 0-2% | – | – | – |
| >13 <= 40 | – | – | – | – |
| >40 <= 80 | – | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
Figure 5. Plant community growth curve (percent production by month). AZ3024, 30.3 10-13" p.z. upland sites. Growth begins in the spring and continues through the summer..
| 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 | 1 | 8 | 18 | 18 | 11 | 14 | 20 | 8 | 2 | 0 | 0 |
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 | 3–15 | |||||
| big galleta | PLRI3 | Pleuraphis rigida | 3–15 | – | ||
| 2 | 3–15 | |||||
| desert needlegrass | ACSP12 | Achnatherum speciosum | 3–15 | – | ||
| 3 | 18–45 | |||||
| Grass, annual | 2GA | Grass, annual | 18–45 | – | ||
| 4 | 3–15 | |||||
| Grass, perennial | 2GP | Grass, perennial | 3–15 | – | ||
|
Forb
|
||||||
| 5 | 3–15 | |||||
| desert Indianwheat | PLOV | Plantago ovata | 3–15 | – | ||
| 6 | 3–15 | |||||
| Forb, annual | 2FA | Forb, annual | 3–15 | – | ||
| 7 | 3–15 | |||||
| Forb, perennial | 2FP | Forb, perennial | 3–15 | – | ||
|
Shrub/Vine
|
||||||
| 8 | 15–30 | |||||
| burrobush | AMDU2 | Ambrosia dumosa | 15–30 | – | ||
| 9 | 3–15 | |||||
| button brittlebush | ENFR | Encelia frutescens | 3–15 | – | ||
| 10 | 3–15 | |||||
| Nevada jointfir | EPNE | Ephedra nevadensis | 3–15 | – | ||
| 11 | 15–30 | |||||
| littleleaf ratany | KRER | Krameria erecta | 15–30 | – | ||
| 12 | 30–45 | |||||
| Eastern Mojave buckwheat | ERFAP | Eriogonum fasciculatum var. polifolium | 30–45 | – | ||
| 13 | 3–15 | |||||
| blackbrush | CORA | Coleogyne ramosissima | 3–15 | – | ||
| 14 | 0–15 | |||||
| turpentine bush | ERLA12 | Ericameria laricifolia | 0–15 | – | ||
| 15 | 15–30 | |||||
| creosote bush | LATR2 | Larrea tridentata | 15–30 | – | ||
| 16 | 0–9 | |||||
| rayless goldenhead | ACSP | Acamptopappus sphaerocephalus | 0–9 | – | ||
| 17 | 0–3 | |||||
| buckhorn cholla | CYACM | Cylindropuntia acanthocarpa var. major | 0–3 | – | ||
| 18 | 3–15 | |||||
| Shrub, other | 2S | Shrub, other | 3–15 | – | ||
|
Tree
|
||||||
| 19 | 0–6 | |||||
| California juniper | JUCA7 | Juniperus californica | 0–6 | – | ||
Interpretations
Animal community
Wildlife species found on this ecological site include coyote, lizards, blacktail jackrabbit, rock squirreltail, snakes and ants.
Supporting information
Type locality
| Location 1: Mohave County, AZ | |
|---|---|
| Township/Range/Section | T19N R17W S10 |
| General legal description | Kingman SE Quad. about 3.5 miles ESE of Griffith. |
Contributors
Harmon Hodgkinson
Harmon S. Hodgkinson
Karlynn Huling
Larry D. Ellicott
Stephen Cassady
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 | |
| Approved by | |
| 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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