Natural Resources
Conservation Service
Ecological site R040XA131AZ
Granitic Hills 10"-13" p.z.
Accessed: 12/21/2024
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): 040X–Sonoran Basin and Range
AZ 40.1 – Upper Sonoran Desert
Elevations range from 2000 to 3200 feet and precipitation averages 10 to 13 inches per year. Vegetation includes saguaro, palo verde, mesquite, creosotebush, triangle bursage, prickly pear, cholla, limberbush, wolfberry, bush muhly, threeawns, ocotillo, and globe mallow. The soil temperature regime is thermic and the soil moisture regime is typic aridic. This unit occurs within the Basin and Range Physiographic Province and is characterized by numerous mountain ranges that rise abruptly from broad, plain-like valleys and basins. Igneous and metamorphic rock classes dominate the mountain ranges and sediments filling the basins represent combinations of fluvial, lacustrine, colluvial and alluvial deposits.
Table 1. Dominant plant species
| Tree |
(1) Parkinsonia microphylla |
|---|---|
| Shrub |
(1) Eriogonum fasciculatum |
| Herbaceous |
(1) Muhlenbergia porteri |
Physiographic features
This site occurs as rough hills and low mountains. In areas, rock outcrop and granite boulders tend to hide the site. Numerous canyons and natural drainages occur within the site.
Table 2. Representative physiographic features
| Landforms |
(1)
Hill
(2) Mountain slope |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,000 – 4,000 ft |
| Slope | 15 – 80% |
| Aspect | Aspect is not a significant factor |
Climatic features
Precipitation in the sub resource area ranges from 10 to 13 inches in the southern part, along the Mexican border with elevations from about 1900 to 3200 feet. Precipitation in the northern part of the resource area ranges from 11 to 14 inches with elevations from about 1700 to 3500 feet. Winter-summer rainfall ratios range from 40%-60% in the southern portions of the land resource unit, to 50%-50% in the central portions, to 60%-40% in the northern part of the land resource unit. As one moves from east to west in this resource area rains become slightly more unpredictable and variable with Coefficients of Variation of annual rainfall equal to 29% at Tucson and 36% at Carefree. Summer rains fall July through Sept., originate in the Gulf of Mexico, and are convective, usually brief, intense thunderstorms. Cool season moisture tends to be frontal, originating in the Pacific and Gulf of California. This winter precipitation falls in widespread storms with long duration and low intensity. Snow is rare and seldom lasts more than an hour or two. May and June are the driest months of the year. Humidity is generally very low.
Winter temperatures are mild, with very few days recording freezing temperatures in the morning. Summer temperatures are warm to hot, with several days in June and July exceeding 105 degrees F.
Both the spring and the summer growing seasons are equally important for perennial grass, forb and shrub growth. Cool and warm season annual forbs and grasses can be common in their respective seasons with above average rainfall. Perennial forage species can remain green throughout the year with available moisture.
Table 3. Representative climatic features
| Frost-free period (average) | 265 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 13 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
These soils are shallow to moderately deep over highly weathered granitic and diabase bedrock. They take rainfall well but available water capacity is limited by depth. Plant-soil relationships are fair. Soils are gravelly and/or cobbly on the surface. The fractured bedrock offers good opportunity for plant root penetration. Rock outcrop will make up from 5-25% of the area.
Soils mapped on this site include: in
SSA-627 Southern Mohave county MU's Cellar-26, Akela-62 & Quilotosa-90 and in
SSA-645 Aguila-Carefree area MU's Cellar-17, Gran-64 & Wickenburg-64.
Table 4. Representative soil features
| Surface texture |
(1) Very gravelly sandy loam (2) Very gravelly loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderately rapid to rapid |
| Soil depth | 10 – 40 in |
| Surface fragment cover <=3" | 35 – 60% |
| Surface fragment cover >3" | 5% |
| Available water capacity (0-40in) |
5 in |
| Soil reaction (1:1 water) (0-40in) |
6.1 – 8.4 |
Ecological dynamics
The plant communities found on an ecological site are naturally variable. Composition and production will vary with yearly conditions, location, aspect, and the natural variability of the soils. The historical climax plant community represents the natural potential plant communities found on relict or relatively undisturbed sites. Other plant communities described here represent plant communities that are known to occur when the site is disturbed by factors such as grazing, fire, or drought.
Production data provided in this site description is standardized to air-dry weight at the end of the summer growing season. The plant communities described in this site description are based on near normal rainfall years.
NRCS uses a Similarity Index to compare existing plant communities to the plant communities described here. Similarity Index is determined by comparing the production and composition of a plant community to the production and composition of a plant community described in this site description. To determine Similarity Index, compare the production (air-dry weight) 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 normal year production shown in the plant community description. If rainfall has been significantly above or below normal, use the total production shown for above or below normal years. If field data is not collected at the end of the summer growing season, then the field data must be corrected to the end of the year production before comparing it to the site description. The growth curve can be used as a guide for estimating production at the end of the summer growing season.
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 native, potential community on this site is a mixture of perennial grasses, forbs and desert shrub species. As the site deteriorates from improper use or the lack of natural fires, desert shrub species and cacti increase to dominate it.
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) |
|---|---|---|---|
| Grass/Grasslike | 275 | 303 | 330 |
| Shrub/Vine | 193 | 206 | 220 |
| Forb | 55 | 69 | 83 |
| Tree | 5 | 8 | 10 |
| Total | 528 | 586 | 643 |
Figure 5. Plant community growth curve (percent production by month). AZ4011, 40.1 10-13" p.z. hill sites. Growth begins in the late winter, goes semi-dormant in the drought period of late May through early July, growth continues in the summer through early fall..
| 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 | 5 | 15 | 20 | 5 | 5 | 10 | 15 | 15 | 5 | 5 | 0 |
Figure 6. Plant community growth curve (percent production by month). AZ4032, 40-3AZ 10-12" p.z. all sites. 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 | 0 | 10 | 15 | 20 | 30 | 20 | 5 | 0 | 0 | 0 |
Additional community tables
Table 6. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 0 | Dominant Perennial Grasses | 140–250 | ||||
| tobosagrass | PLMU3 | Pleuraphis mutica | 83–110 | – | ||
| big galleta | PLRI3 | Pleuraphis rigida | 28–83 | – | ||
| desert needlegrass | ACSP12 | Achnatherum speciosum | 28–55 | – | ||
| 1 | Other Perennial Grasses | 55–110 | ||||
| bush muhly | MUPO2 | Muhlenbergia porteri | 15–30 | – | ||
| slim tridens | TRMU | Tridens muticus | 15–30 | – | ||
| black grama | BOER4 | Bouteloua eriopoda | 10–25 | – | ||
| Arizona cottontop | DICA8 | Digitaria californica | 15–25 | – | ||
| 2 | Misc Perennial Grasses | 55–83 | ||||
| cane bluestem | BOBA3 | Bothriochloa barbinodis | 10–15 | – | ||
| nineawn pappusgrass | ENDE | Enneapogon desvauxii | 10–15 | – | ||
| tanglehead | HECO10 | Heteropogon contortus | 10–15 | – | ||
| curly-mesquite | HIBE | Hilaria belangeri | 5–10 | – | ||
| large-spike bristlegrass | SEMA5 | Setaria macrostachya | 5–10 | – | ||
| sideoats grama | BOCU | Bouteloua curtipendula | 5–10 | – | ||
| squirreltail | ELELE | Elymus elymoides ssp. elymoides | 5–10 | – | ||
| threeawn | ARIST | Aristida | 5–10 | – | ||
| 3 | Annual Grasses | 6–28 | ||||
| Bigelow's bluegrass | POBI | Poa bigelovii | 1–5 | – | ||
| Arizona signalgrass | URAR | Urochloa arizonica | 1–5 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 2–4 | – | ||
| mucronate sprangeltop | LEPAB | Leptochloa panicea ssp. brachiata | 2–4 | – | ||
| Hall's panicgrass | PAHA | Panicum hallii | 1–3 | – | ||
| low woollygrass | DAPU7 | Dasyochloa pulchella | 1–3 | – | ||
| Pacific fescue | VUMIP | Vulpia microstachys var. pauciflora | 0–3 | – | ||
| sixweeks threeawn | ARAD | Aristida adscensionis | 0–3 | – | ||
| sixweeks grama | BOBA2 | Bouteloua barbata | 1–3 | – | ||
| needle grama | BOAR | Bouteloua aristidoides | 0–2 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 0–2 | – | ||
|
Forb
|
||||||
| 4 | Forbs | 28–83 | ||||
| pelotazo | ABIN | Abutilon incanum | 3–8 | – | ||
| dwarf Indian mallow | ABPA3 | Abutilon parvulum | 3–8 | – | ||
| trailing windmills | ALIN | Allionia incarnata | 3–8 | – | ||
| white sagebrush | ARLU | Artemisia ludoviciana | 3–8 | – | ||
| New Mexico silverbush | ARNE2 | Argythamnia neomexicana | 3–8 | – | ||
| desert trumpet | ERIN4 | Eriogonum inflatum | 3–8 | – | ||
| shrubby deervetch | LORI3 | Lotus rigidus | 3–8 | – | ||
| Parry's false prairie-clover | MAPA7 | Marina parryi | 3–8 | – | ||
| wishbone-bush | MILAV | Mirabilis laevis var. villosa | 3–8 | – | ||
| Colorado four o'clock | MIMU | Mirabilis multiflora | 3–8 | – | ||
| Coues' cassia | SECO10 | Senna covesii | 3–8 | – | ||
| globemallow | SPHAE | Sphaeralcea | 3–8 | – | ||
| 5 | Annual Forbs | 6–28 | ||||
| brownfoot | ACWR5 | Acourtia wrightii | 1–3 | – | ||
| fiddleneck | AMSIN | Amsinckia | 1–3 | – | ||
| American wild carrot | DAPU3 | Daucus pusillus | 1–3 | – | ||
| hoary bowlesia | BOIN3 | Bowlesia incana | 0–3 | – | ||
| California suncup | CACA32 | Camissonia californica | 0–3 | – | ||
| phacelia | PHACE | Phacelia | 0–3 | – | ||
| desert Indianwheat | PLOV | Plantago ovata | 1–3 | – | ||
| woolly plantain | PLPA2 | Plantago patagonica | 0–2 | – | ||
| woolly tidestromia | TILA2 | Tidestromia lanuginosa | 0–2 | – | ||
| pepperweed | LEPID | Lepidium | 1–2 | – | ||
| coastal bird's-foot trefoil | LOSAB | Lotus salsuginosus var. brevivexillus | 0–2 | – | ||
| Coulter's lupine | LUSP2 | Lupinus sparsiflorus | 1–2 | – | ||
| combseed | PECTO | Pectocarya | 0–2 | – | ||
| desert larkspur | DEPA | Delphinium parishii | 0–2 | – | ||
| tall mountain larkspur | DESC | Delphinium scaposum | 0–2 | – | ||
| bluedicks | DICAC5 | Dichelostemma capitatum ssp. capitatum | 0–2 | – | ||
| buckwheat | ERIOG | Eriogonum | 1–2 | – | ||
| California poppy | ESCAM | Eschscholzia californica ssp. mexicana | 0–2 | – | ||
| spurge | EUPHO | Euphorbia | 1–2 | – | ||
| spiderling | BOERH2 | Boerhavia | 1–2 | – | ||
| oakfern | GYMNO | Gymnocarpium | 0–1 | – | ||
| mariposa lily | CALOC | Calochortus | 0–1 | – | ||
| clubmoss | LYCOP2 | Lycopodium | 0–1 | – | ||
|
Shrub/Vine
|
||||||
| 6 | Dominant Shrubs | 83–110 | ||||
| Mexican bladdersage | SAME | Salazaria mexicana | 10–20 | – | ||
| Eastern Mojave buckwheat | ERFA2 | Eriogonum fasciculatum | 10–20 | – | ||
| bastardsage | ERWR | Eriogonum wrightii | 10–20 | – | ||
| Nevada jointfir | EPNE | Ephedra nevadensis | 8–15 | – | ||
| Wright's beebrush | ALWR | Aloysia wrightii | 10–15 | – | ||
| brickellbush | BRICK | Brickellia | 5–10 | – | ||
| fairyduster | CAER | Calliandra eriophylla | 5–10 | – | ||
| slender janusia | JAGR | Janusia gracilis | 2–8 | – | ||
| 7 | Other Shrubs | 55–83 | ||||
| littleleaf ratany | KRER | Krameria erecta | 8–15 | – | ||
| plains blackfoot | MELE2 | Melampodium leucanthum | 5–10 | – | ||
| Mojave sage | SAMO3 | Salvia mohavensis | 5–10 | – | ||
| rock sage | SAPI2 | Salvia pinguifolia | 5–10 | – | ||
| toothleaf goldeneye | VIDE3 | Viguiera dentata | 5–10 | – | ||
| Arizona wrightwort | CAAR7 | Carlowrightia arizonica | 5–10 | – | ||
| California fagonbush | FALA | Fagonia laevis | 5–10 | – | ||
| Newberry's velvetmallow | HONE | Horsfordia newberryi | 5–10 | – | ||
| narrowleaf silverbush | ARLA12 | Argythamnia lanceolata | 6–9 | – | ||
| desert rosemallow | HICO | Hibiscus coulteri | 3–8 | – | ||
| desert lavender | HYEM | Hyptis emoryi | 3–8 | – | ||
| buckwheat | ERIOG | Eriogonum | 3–8 | – | ||
| San Felipe dogweed | ADPO | Adenophyllum porophylloides | 3–8 | – | ||
| bedstraw | GALIU | Galium | 2–5 | – | ||
| 8 | Misc. Shrubs | 28–55 | ||||
| alderleaf mountain mahogany | CEMO2 | Cercocarpus montanus | 2–10 | – | ||
| Sonoran scrub oak | QUTU2 | Quercus turbinella | 5–10 | – | ||
| sugar sumac | RHOV | Rhus ovata | 3–8 | – | ||
| whitethorn acacia | ACCO2 | Acacia constricta | 2–8 | – | ||
| catclaw acacia | ACGR | Acacia greggii | 3–5 | – | ||
| rayless goldenhead | ACSP | Acamptopappus sphaerocephalus | 1–5 | – | ||
| yerba de pasmo | BAPT | Baccharis pteronioides | 1–5 | – | ||
| crucifixion thorn | CAHO3 | Canotia holacantha | 1–5 | – | ||
| Indian mallow | ABUTI | Abutilon | 1–5 | – | ||
| snakeweed | GUTIE | Gutierrezia | 1–5 | – | ||
| desert-thorn | LYCIU | Lycium | 3–5 | – | ||
| American threefold | TRCA8 | Trixis californica | 1–5 | – | ||
| Schott's pygmycedar | PESC4 | Peucephyllum schottii | 2–5 | – | ||
| slender poreleaf | POGR5 | Porophyllum gracile | 1–5 | – | ||
| jojoba | SICH | Simmondsia chinensis | 3–5 | – | ||
| turpentinebroom | THMO | Thamnosma montana | 1–5 | – | ||
| whitestem paperflower | PSCO2 | Psilostrophe cooperi | 2–4 | – | ||
| Lemmon's ragwort | SELE8 | Senecio lemmonii | 2–4 | – | ||
| woody crinklemat | TICAC | Tiquilia canescens var. canescens | 1–3 | – | ||
| lacy tansyaster | MAPIP4 | Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida | 1–3 | – | ||
| snapdragon penstemon | KEANM | Keckiella antirrhinoides ssp. microphylla | 1–3 | – | ||
| Florida hopbush | DOVI | Dodonaea viscosa | 1–3 | – | ||
| brittlebush | ENFA | Encelia farinosa | 1–3 | – | ||
| desert yellow fleabane | ERLI | Erigeron linearis | 1–3 | – | ||
| 9 | Succulents | 6–28 | ||||
| desert agave | AGDE | Agave deserti | 1–2 | – | ||
| saguaro | CAGI10 | Carnegiea gigantea | 1–2 | – | ||
| buckhorn cholla | CYACA2 | Cylindropuntia acanthocarpa var. acanthocarpa | 1–2 | – | ||
| teddybear cholla | CYBI9 | Cylindropuntia bigelovii | 1–2 | – | ||
| Gila County liveforever | DUCO | Dudleya collomiae | 1–2 | – | ||
| Engelmann's hedgehog cactus | ECEN | Echinocereus engelmannii | 1–2 | – | ||
| hedgehog cactus | ECHIN3 | Echinocereus | 1–2 | – | ||
| candy barrelcactus | FEWI | Ferocactus wislizeni | 1–2 | – | ||
| ocotillo | FOSP2 | Fouquieria splendens | 1–2 | – | ||
| globe cactus | MAMMI | Mammillaria | 1–2 | – | ||
| beargrass | NOLIN | Nolina | 1–2 | – | ||
| beavertail pricklypear | OPBA2 | Opuntia basilaris | 1–2 | – | ||
| dollarjoint pricklypear | OPCH | Opuntia chlorotica | 1–2 | – | ||
| cactus apple | OPEN3 | Opuntia engelmannii | 1–2 | – | ||
| banana yucca | YUBA | Yucca baccata | 1–2 | – | ||
|
Tree
|
||||||
| 10 | Tree | 5–10 | ||||
| yellow paloverde | PAMI5 | Parkinsonia microphylla | 5–10 | – | ||
Interpretations
Animal community
This site is suitable for yearlong grazing by all classes of livestock. Yearlong stocking results in overuse of canyon bottoms, ridgetops and saddles with moany other areas deteriorating from little or no use. Fencing, to control use of the site, along with water developments and stock trails may all be needed to improve grazing distribution and facilitate management.
The site has good cover and a wide diversty of forage plants with variable green seasons. Natural water is lacking and stockwater developments are important to wildlife in these areas.
Recreational uses
The landscape quality consists of grassy slopes interrupted by bouldery rock-outcrop areas. In good winter rainfall years, desert wildflowers lend much color to the site.
Very few days in the fall, winter and spring restrict outdoor activities. Afternoon temperatures in June, July and August make such activities less enjoyable.
Activities include hunting, prospecting, hiking, horseback riding and photography.
Wood products
None.
Other products
Mining occurs in places on this site.
Supporting information
Type locality
| Location 1: Yavapai County, AZ | |
|---|---|
| Township/Range/Section | T10N R7W S9 |
| General legal description | Phoenix F.O. Section 17, T7N, R6W Vulture Mountains, Echeverria Ranch. Prescott F.O. Section 9, T10N, R7W Date Creek Mountains, Knight Ranch. Prescott F.O. Section 3, T9N, R4W Stanton Hills, JJ Coughlin Ranch. |
Contributors
Larry D. Ellicott
Unknown
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:
Print Options
Sections
Font
Other
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.
Click on box and path labels to scroll to the respective text.