Natural Resources
Conservation Service
Ecological site R030XB210AZ
Limestone Hills 6-9" p.z.
Last updated: 10/21/2024
Accessed: 11/13/2024
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 on steeply sloping uplands (slopes 15%-65%). Soils are very shallow to shallow over limestone.
Associated sites
R030XB205AZ |
Sandy Loam Upland 6-10" p.z. Limy Subsurface, Gravelly |
---|---|
R030XB208AZ |
Gypsum Hills 6-9" p.z. |
R030XB214AZ |
Limy Upland 6-9" p.z. |
R030XB222AZ |
Gypsum Hills 6-9" p.z. Alkaline |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Ephedra nevadensis |
Herbaceous |
(1) Pleuraphis rigida |
Physiographic features
This site occurs in an upland position as hills and escarpments associated with rock outcrops. Geologic formations associated with the site include Callville limestone, Kaibab Limestone, Coconino sandstone and Supi formation. Slopes range from 35 to 70 percent.
Table 2. Representative physiographic features
Landforms |
(1)
Escarpment
(2) Hill |
---|---|
Flooding frequency | None |
Ponding frequency | None |
Elevation | 1,600 – 3,500 ft |
Slope | 35 – 70% |
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 very shallow to shallow. The surface texture is extremely gravelly loam. The subsurface texture is extremely gravelly loam. The parent material is colluvium from sedimentary formations. The available water holding capacity is very low due to the shallow nature of the soil. The hazard of erosion by water is very severe and by wind is slight. The soil is calcareous throughout the profile.
A typical soil profile is a follows:
0 to 1 inch - extremely gravelly loam
1 to 7 inches - extremely gravelly loam
7 inches - limestone bedrock
Soil map units correlated to this ecological site include 623034, Hindu soil, Shivwits Area SSA.
Table 4. Representative soil features
Surface texture |
(1) Extremely gravelly loam |
---|---|
Family particle size |
(1) Loamy |
Drainage class | Well drained |
Permeability class | Moderate to moderately rapid |
Soil depth | 5 – 20 in |
Surface fragment cover <=3" | 35 – 65% |
Surface fragment cover >3" | 20% |
Available water capacity (0-40in) |
0.3 – 0.5 in |
Calcium carbonate equivalent (0-40in) |
15 – 35% |
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) |
35 – 65% |
Subsurface fragment volume >3" (Depth not specified) |
20% |
Ecological dynamics
Limestone Hills, 6"-9" p.z., is a mixed shrubland. Scattered perennial grasses and forbs are well-distributed across the site. Annual forbs and grasses flourish following rainfall. Natural disturbances are rare. Following introduction of non-native annuals (forbs and/or grasses), seasonal herbaceous production increases following wet winters. Assorted half-shrubs are widely scattered.
State and transition model
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State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Historic Climax Plant Community
Community 1.1
Historic Climax Plant Community
The dominant aspect of this ecological site is a desert shrub-grassland. No one species dominates the aspect, although the cacti species, Utah agave, and Fremont dalea are very visible when in flower. With disturbance plants that will increase are snakeweed and plants that will invade are red brome. The site's total annual production by weight (air-dried) is comprised of: grasses and grasslike plants 20 to 30 percent, forbs 5 to 15 percent, shrubs 60 to 70 percent and trees 0 to 3 percent.
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 | 70 | 145 | 237 |
Grass/Grasslike | 24 | 55 | 102 |
Forb | 6 | 20 | 51 |
Tree | 0 | 5 | 10 |
Total | 100 | 225 | 400 |
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 | – | – | 1-3% | – |
>1 <= 2 | – | – | – | – |
>2 <= 4.5 | – | 8-12% | – | – |
>4.5 <= 13 | – | – | – | – |
>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). AZ3038, 35.5 6-9" p.z. Nevada Mormon tea. Growth occurs mostly in the spring and early summer using stored winter moisture..
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 | 15 | 25 | 20 | 15 | 15 | 10 | 0 | 0 | 0 | 0 |
Figure 7. Plant community growth curve (percent production by month). AZ3070, 30.23 6-9" p.z. big galleta. Growth begins in the spring, 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 | 15 | 5 | 0 | 10 | 45 | 15 | 0 | 0 | 0 |
Figure 8. Plant community growth curve (percent production by month). AZ3075, 30.23 6-9" p.z. white ratany. Most growth occurs in the spring, some growth occurs in the summer. Flowers 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 | 0 | 5 | 20 | 35 | 5 | 10 | 15 | 10 | 0 | 0 | 0 |
Figure 9. Plant community growth curve (percent production by month). AZ3077, 30.23 6-9" p.z. bush muhly. Growth begins in the spring, most growth occurs during the summer rainy season, green most of the year..
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 | 5 | 5 | 5 | 5 | 15 | 40 | 20 | 5 | 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 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 forb and grass seed.
Restoration pathway R2A
State 2 to 1
None known.
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 | 2–11 | |||||
bush muhly | MUPO2 | Muhlenbergia porteri | 2–11 | – | ||
2 | 4–14 | |||||
big galleta | PLRI3 | Pleuraphis rigida | 4–14 | – | ||
3 | 2–14 | |||||
threeawn | ARIST | Aristida | 2–14 | – | ||
4 | 0–11 | |||||
slim tridens | TRMU | Tridens muticus | 0–11 | – | ||
5 | 0–9 | |||||
low woollygrass | DAPU7 | Dasyochloa pulchella | 0–9 | – | ||
6 | 0–4 | |||||
Indian ricegrass | ACHY | Achnatherum hymenoides | 0–4 | – | ||
7 | 0–11 | |||||
Grass, perennial | 2GP | Grass, perennial | 0–11 | – | ||
desert needlegrass | ACSP12 | Achnatherum speciosum | 0–11 | – | ||
common wolfstail | LYPH | Lycurus phleoides | 0–11 | – | ||
8 | 0–2 | |||||
Grass, annual | 2GA | Grass, annual | 0–2 | – | ||
sixweeks grama | BOBA2 | Bouteloua barbata | 0–2 | – | ||
Forb
|
||||||
9 | 0–7 | |||||
desert globemallow | SPAM2 | Sphaeralcea ambigua | 0–7 | – | ||
10 | 0–9 | |||||
desert trumpet | ERIN4 | Eriogonum inflatum | 0–9 | – | ||
11 | 2–18 | |||||
Forb, perennial | 2FP | Forb, perennial | 2–9 | – | ||
desert marigold | BAMU | Baileya multiradiata | 2–9 | – | ||
lettuce | LACTU | Lactuca | 2–9 | – | ||
beardtongue | PENST | Penstemon | 2–9 | – | ||
phlox | PHLOX | Phlox | 2–9 | – | ||
12 | 2–22 | |||||
Forb, annual | 2FA | Forb, annual | 2–11 | – | ||
buckwheat | ERIOG | Eriogonum | 2–11 | – | ||
spurge | EUPHO | Euphorbia | 2–11 | – | ||
blazingstar | MENTZ | Mentzelia | 2–11 | – | ||
phacelia | PHACE | Phacelia | 2–11 | – | ||
Shrub/Vine
|
||||||
13 | 11–22 | |||||
Nevada jointfir | EPNE | Ephedra nevadensis | 11–22 | – | ||
14 | 4–11 | |||||
button brittlebush | ENFR | Encelia frutescens | 4–11 | – | ||
16 | 7–11 | |||||
littleleaf ratany | KRER | Krameria erecta | 0–11 | – | ||
white ratany | KRGR | Krameria grayi | 0–11 | – | ||
17 | 0–11 | |||||
Fremont's dalea | PSFRF | Psorothamnus fremontii var. fremontii | 0–11 | – | ||
18 | 2–7 | |||||
starry bedstraw | GASTE2 | Galium stellatum ssp. eremicum | 2–7 | – | ||
19 | 10–20 | |||||
pricklypear | OPUNT | Opuntia | 10–20 | – | ||
20 | 0–11 | |||||
creosote bush | LATR2 | Larrea tridentata | 0–11 | – | ||
21 | 0–11 | |||||
burrobush | AMDU2 | Ambrosia dumosa | 0–11 | – | ||
22 | 0–11 | |||||
broom snakeweed | GUSA2 | Gutierrezia sarothrae | 0–11 | – | ||
23 | 0–22 | |||||
blackbrush | CORA | Coleogyne ramosissima | 0–22 | – | ||
24 | 34–79 | |||||
Shrub (>.5m) | 2SHRUB | Shrub (>.5m) | 0–11 | – | ||
rayless goldenhead | ACSP | Acamptopappus sphaerocephalus | 0–11 | – | ||
Utah agave | AGUT | Agave utahensis | 0–11 | – | ||
Wright's beebrush | ALWR | Aloysia wrightii | 0–11 | – | ||
fourwing saltbush | ATCA2 | Atriplex canescens | 0–11 | – | ||
brickellbush | BRICK | Brickellia | 0–11 | – | ||
spiny hopsage | GRSP | Grayia spinosa | 0–11 | – | ||
burrobrush | HYSA | Hymenoclea salsola | 0–11 | – | ||
winterfat | KRLA2 | Krascheninnikovia lanata | 0–11 | – | ||
water jacket | LYAN | Lycium andersonii | 0–11 | – | ||
Utah mortonia | MOUT | Mortonia utahensis | 0–11 | – | ||
desert almond | PRFA | Prunus fasciculata | 0–11 | – | ||
whitestem paperflower | PSCO2 | Psilostrophe cooperi | 0–11 | – | ||
Stansbury cliffrose | PUST | Purshia stansburiana | 0–11 | – | ||
Mexican bladdersage | SAME | Salazaria mexicana | 0–11 | – | ||
turpentinebroom | THMO | Thamnosma montana | 0–11 | – | ||
American threefold | TRCA8 | Trixis californica | 0–11 | – | ||
Tree
|
||||||
15 | 2–7 | |||||
Eastern Mojave buckwheat | ERFA2 | Eriogonum fasciculatum | 2–7 | – | ||
25 | 0–7 | |||||
Joshua tree | YUBR | Yucca brevifolia | 0–7 | – |
Interpretations
Supporting information
Contributors
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 | 10/21/2024 |
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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