Natural Resources
Conservation Service
Ecological site R040XB207AZ
Limy Fan 7"-10" p.z.
Accessed: 11/24/2024
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 40.2 – Middle Sonoran Desert
Elevations range from 1200 to 2000 feet and precipitation averages 7 to 10 inches per year. Vegetation includes saguaro, palo verde, creosotebush, bursage, ratany, brittlebush, prickly pear, cholla, desert saltbush, wolfberry bush muhly, threeawns, and big galleta. The soil temperature regime is hyperthermic 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.
Classification relationships
MLRA 40, Sonoran Basin and Range
Forest Service Section 322B, Sonoran Desert
EPA Level III Ecoregion 81, Sonoran Basin and Range.
91% of MLRA overlap.
Ecological site concept
Limy fan ecological site occurs on gently sloping uplands. All moisture is received from precipitation without additional moisture inputs from on-site surface flow. Slopes are generally less than three percent. The calcareous, alluvial soils are deep with less than 35% rock fragments.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Larrea tridentata |
| Herbaceous |
Not specified |
Physiographic features
This site occurs on fan terraces and stream terraces. Slopes are from 1 to 3%. Elevations range from about 1000 to 2000 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Fan
(2) Stream terrace |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 305 – 610 m |
| Slope | 1 – 3% |
| Aspect | Aspect is not a significant factor |
Climatic features
Precipitation in the sub-resource area ranges from 7 to 10 inches; mean precipitation from weather stations listed below is 8.35 inches. Elevations range from 900 to 2050 feet. Winter-summer rainfall ratios range from 40% to 60% in the southern part along the international boundary, to 60% to 40% in the central and northern parts of the sub-resource area. As one moves from east to west in this resource area rains become more unpredictable and variable with Coefficients of Variation of annual rainfall equal to 38% at Florence and 46% at Aguila. Summer rains fall July- September, originate in the Gulf of Mexico, and are convective, usually brief, intense thunderstorms. Summer precipitation is extremely erratic and undependable in this area. Cool season moisture tends to be frontal, originates in the Pacific and Gulf of California, and falls in widespread storms with long duration and low intensity. These cool season rains provide the dependable moisture supply for vegetation in the area. Snow is very rare and usually melts on contact. May-June is the driest time of the year. Humidity is very low.
Temperatures fluctuate about 30 degrees from nighttime lows to daytime highs. Winter temperatures are very mild with very few days recording freezing. Summertime temperatures are hot to very hot with many days in June-July exceeding 105 degrees F. High and low temperatures recorded at the stations listed below are 125 and 11 degreees Farenheit. The temperature table below shows the average monthly high and low temperatures for all listed stations.
Both the spring and the summer growing seasons are equally important for perennial grass, forb and shrub growth; plant growing conditions are favorable nearly yearlong. Annual forb and grass growth is highly dependent upon rainfall; annuals can dominate the landscape with unusually high precipitation. Perennial forbs and grasses can remain green throughout the year with available moisture.
Table 3. Representative climatic features
| Frost-free period (average) | 291 days |
|---|---|
| Freeze-free period (average) | 337 days |
| Precipitation total (average) | 229 mm |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Figure 4. Annual precipitation pattern
Figure 5. Annual average temperature pattern
Climate stations used
-
(1) FLORENCE [USC00023027], Florence, AZ
-
(2) LAVEEN 3 SSE [USC00024829], Phoenix, AZ
-
(3) ORGAN PIPE CACTUS NM [USC00026132], West Pima County, AZ
-
(4) KOFA MINE [USC00024702], Wellton, AZ
-
(5) LITCHFIELD PARK [USC00024977], Goodyear, AZ
-
(6) PHOENIX SKY HARBOR INTL AP [USW00023183], Phoenix, AZ
-
(7) CASA GRANDE [USC00021306], Casa Grande, AZ
Influencing water features
This site does not benefit from run-on moisture. Rills are common and continuous in areas without gravel cover. Water flow patterns are common and continuous, occupying 15-20 percent of the area. Gullies are not present.
Soil features
These are deep soils formed in loamy alluvium of moderate age and from mixed origins. They range from sandyloam to loam surface textures. They are calcareous throughout. They are not skeletal. Plant-soil moisture relationships are poor to fair. On areas without gravel cover, pedestals accumulate under woody species 2 to 5 inches high. Soil compaction is not normal on the site. Bare ground ranges from 10 to 60 percent on the site. The soil surface is resistant to erosion due to surface crusting formed by raindrop impact.
This site is mapped in 9 Soil Survey areas across the CRA's in South western Arizona.
Soils mapped on this site include: SSA-627 Southern Mohave County MU's Rillino-37, 97 & 98, Tres Hermanos-35 & 98; SSA-645 Aguila-Carefree area MU's Antho-1 & 2, Estrella-50, Gila-54, Gilman-55 & 57, Glenbar-60, Rillito-70, 101, 116 & 118, Mohall (calcareous surface)-76 & 78, Mohave-84 & 87, Tremant(calcareous surface)-112 & 113, Tres Hermanos-120, Vallencia-124; SSA-651 Central Maricopa County MU's Antho-AbA, AbB, AdB, Ae, AfA, AfB, AGB, AHC, AkB, AL, AM, GM & Go3, Coolidge-Cp, CrB, Cs & CV, Estrella-Es, Gilman-GgA, GgB, GM, GN & Go3, Laveen-CV, GN, HM, Lb, LcA, LcB, LF & MV, Perryville-Pa, PeA, PeB, PRB & RpE, Rillito-GxA, GxB, GYD, HrB, PRB, RaA, RaB, RbB, RhB, RpE, TrA, TrB & TSC, Tucson-Tu & Tw, Valencia-AM, Va & Vc & Wintersburg-Wg; SSA-653 Gila Bend-Ajo area MU's Coolidge-20, Dateland-5 & 14, Denure (calcareous surface)-20 & 21, & Rillito-21 & 37; SSA-658 Gila River Indian Reservation MU's Denure (calcareous surface)-13 & 14, & Pahaka(calcareous surface)-13 & 14; SSA-659 Western Pinal County MU's Coolidge-11, Dateland-13, Denure(calcareous surface)-16, 17, 18 & 44, Laveen-28, & Tremant-44; SSA-661 Eastern Pinal-Souther Gila Counties MU's Coolidge-265, Dateland-206 & 345, Denure(calcareous surface)-206, 320 & 340, Laveen-213 & 335, Pinamt(<50% gravels)-565, & Tremant-565; SSA-669 Eastern Pima County MU's Dateland-21, Denure(calcareous surface)-21 & Pahaka(calcareous surface)-53; SSA-703 Tohono O'odham area MU's Dateland-15, Denure(calcareous surface)-15 & 19, Rillito-33, Sasco-55 & Wintersburg-62. Subsurface texture may include fine or coarse loamy.
Table 4. Representative soil features
| Surface texture |
(1) Gravelly sandy loam (2) Gravelly fine sandy loam (3) Gravelly loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained |
| Permeability class | Moderately slow to moderately rapid |
| Soil depth | 152 cm |
| Surface fragment cover <=3" | 0 – 15% |
| Surface fragment cover >3" | 0% |
| Available water capacity (0-101.6cm) |
21.34 – 27.43 cm |
| Calcium carbonate equivalent (0-101.6cm) |
3 – 25% |
| Electrical conductivity (0-101.6cm) |
0 – 2 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 |
| Soil reaction (1:1 water) (0-101.6cm) |
7.9 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
0 – 15% |
| Subsurface fragment volume >3" (Depth not specified) |
0% |
Ecological dynamics
The 40-2AZ Limy Fan Reference State (see State and Transition Model below) is dominated by creosote and the sub-shrubs, bursage and ratany. The perennial grasses, big galleta and bush muhly, are generally confined to areas with additional moisture inputs such as rills or small depressions; other perennial grasses may occasionally be found. Several species of shrubs, cacti, other succulents and forbs are represented in the plant community. Annual forbs and grasses proliferate after nearly any good rainfall. The aspect is open shrubland.
Anthropogenic changes in the plant community and ecosystem function occur as disturbances to the Reference State occur. Long-term disturbances, such as introduction of non-native plant species, unmanaged livestock grazing can exceed the site’s resilience or ability to recover. The long-lasting changes in hydrologic functioning, site stability and biotic integrity are reflected in the change in productivity and plant community. Rainfall does not favor site recovery after a threshold is crossed; therefore, complete restoration to the Reference State is not feasible. Of course, cessation of off-road vehicle travel, planned road/trail development and application of prescribed grazing will limit transition to a less desirable state.
Fire from human ignition may occasionally occur if dry standing crop of annual forb (either native or non-native forbs) is exceptionally high; natural fire seldom occurs. The Barren State results from a burn.
Non-native annual forbs and/or non-native annual grasses may become present on Limy Fans through natural spread (wind, water) or mechanical transport (via contaminated hay, vehicles, livestock, or wildlife); although present, non-natives may co-exist with native annuals. However, after non-native annual forb seed is present, disturbance may result in annual forbs dominating the understory (Exotic Annuals State). The shrubland aspect, soil stability, and hydrologic functioning remain similar to the Reference State; however, biotic integrity of the site may be altered since the non-native annuals may permanently replace natives.
Long-term, continuous grazing will eliminate forage species from the RPC pushing the site into the Shrub State. Perennial grasses are first to fall out of the community followed by perennial forbs and ratany. Bursage may persist in low numbers. Site hydrology will be affected with decreased infiltration and increased run-off.
The Eroded State occurs as run-off accelerates soil erosion forming pedestals and gullies. Roads and vehicle trails alter surface water flow on either the Reference State or the Shrub Dominated State channel water, creating accelerated run-off within small points causing nick-points of headcuts. Roads can become entrenched. The Shrub Dominated State is vulnerable to transitioning to the Eroded State due to lack of cover.
State and transition model
Figure 6. 40-2AZ Limy Fan, 7-10" p.z. STM
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
States 1 and 5 (additional transitions)
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 5 submodel, plant communities
State 1
Reference
Community 1.1
Reference Plant Community
Figure 7. Limy Fan, 7-10" p.z., Reference Community
The potential plant community is a mixture of desert shrubs and sub-shrubs with cacti, perennial grasses and annuals well represented throughout. Creosote dominates with a wide range of other shrubs present, such as wolfberry, palo verde, graythorn, or ironwood, sparsely present. Sub-shrubs, an even mix of bursage and ratany, make up the sub-dominant, woody understory. Perennial grasses are somewhat constrained to waterflow paths and can be represented by a variety of species but most commonly bush muhly and big galleta are found. A variety of succulents, cholla species, prickly pears, cereus and barrel cacti are scattered on the site; saguaro may or may not be present. A wide variety of annual forbs and annual grasses are found nearly year-round after precipitation events due to the favorable growing conditions; annual production from annuals can exceed 100 #s/acre during a wet year. The aspect is open shrubland. The soil surface generally lacks a protective gravel cover, but usually has extensive cryptogam cover. Crytogam cover ranges from 10 to 15% on the site. These lichens are communities made up of associations of blue green algae and fungi, which fix atmospheric nitrogen and form surface crusts that reduce erosion by both wind and water. With severe disturbance of these crusts, sheet and rill erosion can accelerate and dust blowing can be a problem. Plant populations for creosotebush ranges from 100 to 700 plants per acre. Some areas of this site receive rare flooding (once every 20 to 50 years). These events may cause severe mortality of creosotebush. Reestablishment is quick, however and the plant community soon is back to normal.
Figure 8. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
|---|---|---|---|
| Shrub/Vine | 157 | – | 314 |
| Forb | 20 | – | 118 |
| Grass/Grasslike | 20 | – | 78 |
| Total | 197 | – | 510 |
State 2
Exotic Annuals
Community 2.1
Exotic Annual Understory
A few cool season, introduced annuals like; filaree, mediterranean grass and london rocket mustard can become entrenched in areas of this site and compete with native annual forbs and grasses. No mechanism to remove non-native annuals is known and once non-native annuals dominate this ecological site, disturbance drivers will follow the transitional paths as those from the reference state; therefore, States 3, 4, and 5 may have non-native annuals dominate the annual forbs and grass communities. Wildlife habitat may be impaired because the non-native forbs do not provide adequate food and cover. Fire fuel loading after a flourish of either non-native or native annuals may carry fire.
State 3
Shrub
Community 3.1
Creosote Community
Figure 9. Limy Fan, 7-10" p.z., Creosote Community
Annual forbs and grasses (both native and exotic) will fluctuate with climate. This appears to be a stable community without fire or other disturbance like continuous grazing
State 4
Barren
Community 4.1
Annual Forb and Annual Grass Community
Occasionally, after an unusually high production of annual forbs, a fire will burn. Natural fires are extremely rare, however, and if Limy Fan burns it is generally from human ignition.
State 5
Eroded
Community 5.1
Eroded
Figure 10. Limy Fan, 7-10" p.z., Eroded
Transition T1A
State 1 to 2
Transition T1B
State 1 to 3
Transition T1C
State 1 to 4
Transition T1D
State 1 to 5
Restoration pathway R2A
State 2 to 1
Conservation practices
| Fence | |
|---|---|
| Firebreak | |
| Livestock Pipeline | |
| Pumping Plant | |
| Access Road | |
| Watering Facility | |
| Water Harvesting Catchment | |
| Water Well | |
| Upland Wildlife Habitat Management | |
| Livestock Shade Structure | |
| Livestock Use Area Protection | |
| Prescribed Grazing | |
| TA Planning | |
| TA Design | |
| TA Application | |
| TA Check-Out | |
| Fish and Wildlife Structure | |
| Fish and Wildlife Habitat Plan - Written | |
| Fish and Wildlife Habitat Plan - Applied |
Restoration pathway R3A
State 3 to 1
Conservation practices
| Critical Area Planting | |
|---|---|
| Fence | |
| Firebreak | |
| Livestock Pipeline | |
| Pumping Plant | |
| Rock Barrier | |
| Access Road | |
| Trails and Walkways | |
| Watering Facility | |
| Water Harvesting Catchment | |
| Water Well | |
| Upland Wildlife Habitat Management | |
| Early Successional Habitat Development/Management | |
| Controlled Livestock Lounging Area | |
| Livestock Shade Structure | |
| Snow Harvesting | |
| Record Keeping | |
| Well Plugging | |
| Livestock Use Area Protection | |
| Prescribed Grazing | |
| TA Planning | |
| TA Design | |
| TA Application | |
| TA Check-Out | |
| Dust Control on Unpaved Roads and Surfaces | |
| Road/Trail/Landing Closure and Treatment | |
| Fish and Wildlife Structure | |
| Fish and Wildlife Habitat Plan - Written | |
| Fish and Wildlife Habitat Plan - Applied | |
| Dust Control on Unpaved Roads and Surfaces |
Transition T3A
State 3 to 4
Restoration pathway R4A
State 4 to 1
Conservation practices
| Critical Area Planting | |
|---|---|
| Fence | |
| Firebreak | |
| Access Control | |
| Livestock Pipeline | |
| Pumping Plant | |
| Rock Barrier | |
| Trails and Walkways | |
| Watering Facility | |
| Water Harvesting Catchment | |
| Water Well | |
| Upland Wildlife Habitat Management | |
| Early Successional Habitat Development/Management | |
| Controlled Livestock Lounging Area | |
| Livestock Shade Structure | |
| Snow Harvesting | |
| Record Keeping | |
| Well Plugging | |
| Livestock Use Area Protection | |
| Prescribed Grazing | |
| TA Planning | |
| TA Design | |
| TA Application | |
| TA Check-Out | |
| Dust Control on Unpaved Roads and Surfaces | |
| Road/Trail/Landing Closure and Treatment | |
| Fish and Wildlife Structure | |
| Fish and Wildlife Habitat Plan - Written | |
| Fish and Wildlife Habitat Plan - Applied | |
| Dust Control on Unpaved Roads and Surfaces |
Restoration pathway R4B
State 4 to 3
Conservation practices
| Critical Area Planting | |
|---|---|
| Water Well Decommissioning | |
| Fence | |
| Firebreak | |
| Access Control | |
| Livestock Pipeline | |
| Pumping Plant | |
| Rock Barrier | |
| Trails and Walkways | |
| Watering Facility | |
| Water Harvesting Catchment | |
| Water Well | |
| Upland Wildlife Habitat Management | |
| Early Successional Habitat Development/Management | |
| Controlled Livestock Lounging Area | |
| Livestock Shade Structure | |
| Snow Harvesting | |
| Well Plugging | |
| Livestock Use Area Protection | |
| Prescribed Grazing | |
| TA Planning | |
| TA Design | |
| TA Application | |
| TA Check-Out | |
| Well Water Testing | |
| Dust Control on Unpaved Roads and Surfaces | |
| Road/Trail/Landing Closure and Treatment | |
| Fish and Wildlife Structure | |
| Grazing Management Plan - Written | |
| Grazing Management Plan - Applied | |
| Fish and Wildlife Habitat Plan - Written | |
| Fish and Wildlife Habitat Plan - Applied | |
| Dust Control on Unpaved Roads and Surfaces |
Transition T4A
State 4 to 5
Additional community tables
Table 6. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | Perennial Grasses | 17–34 | ||||
| bush muhly | MUPO2 | Muhlenbergia porteri | 2–6 | – | ||
| whiplash pappusgrass | PAVA2 | Pappophorum vaginatum | 0–2 | – | ||
| big galleta | PLRI3 | Pleuraphis rigida | 0–2 | – | ||
| plains bristlegrass | SEVU2 | Setaria vulpiseta | 0–2 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 0–2 | – | ||
| slim tridens | TRMU | Tridens muticus | 0–2 | – | ||
| purple threeawn | ARPU9 | Aristida purpurea | 0–2 | – | ||
| blue threeawn | ARPUN | Aristida purpurea var. nealleyi | 0–2 | – | ||
| Parish's threeawn | ARPUP5 | Aristida purpurea var. parishii | 0–2 | – | ||
| Wright's threeawn | ARPUW | Aristida purpurea var. wrightii | 0–2 | – | ||
| spidergrass | ARTE3 | Aristida ternipes | 0–2 | – | ||
| spidergrass | ARTEG | Aristida ternipes var. gentilis | 0–2 | – | ||
| low woollygrass | DAPU7 | Dasyochloa pulchella | 0–2 | – | ||
| Arizona cottontop | DICA8 | Digitaria californica | 0–2 | – | ||
| 2 | Annual Grasses | 3–56 | ||||
| sixweeks threeawn | ARAD | Aristida adscensionis | 0–11 | – | ||
| prairie threeawn | AROL | Aristida oligantha | 0–11 | – | ||
| needle grama | BOAR | Bouteloua aristidoides | 0–11 | – | ||
| Arizona signalgrass | URAR | Urochloa arizonica | 0–8 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 0–8 | – | ||
| Pacific fescue | VUMIP | Vulpia microstachys var. pauciflora | 0–6 | – | ||
| sixweeks grama | BOBA2 | Bouteloua barbata | 0–6 | – | ||
| Rothrock's grama | BORO2 | Bouteloua rothrockii | 0–6 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 0–1 | – | ||
| feather fingergrass | CHVI4 | Chloris virgata | 0–1 | – | ||
| canyon cupgrass | ERLE7 | Eriochloa lemmonii | 0–1 | – | ||
| desert lovegrass | ERPEM | Eragrostis pectinacea var. miserrima | 0–1 | – | ||
| tufted lovegrass | ERPEP2 | Eragrostis pectinacea var. pectinacea | 0–1 | – | ||
| Mexican sprangletop | LEFUU | Leptochloa fusca ssp. uninervia | 0–1 | – | ||
| mucronate sprangletop | LEPA6 | Leptochloa panicea | 0–1 | – | ||
| delicate muhly | MUFR | Muhlenbergia fragilis | 0–1 | – | ||
| littleseed muhly | MUMI | Muhlenbergia microsperma | 0–1 | – | ||
| Bigelow's bluegrass | POBI | Poa bigelovii | 0–1 | – | ||
| Eastwood fescue | VUMIC | Vulpia microstachys var. ciliata | 0–1 | – | ||
|
Forb
|
||||||
| 3 | Perennial Forbs | 39–56 | ||||
| evening primrose | OENOT | Oenothera | 0–6 | – | ||
| desert globemallow | SPAM2 | Sphaeralcea ambigua | 0–6 | – | ||
| pricklyleaf dogweed | THAC | Thymophylla acerosa | 0–1 | – | ||
| Tumamoc globeberry | TUMA | Tumamoca macdougalii | 0–1 | – | ||
| dwarf desertpeony | ACNA2 | Acourtia nana | 0–1 | – | ||
| weakleaf bur ragweed | AMCO3 | Ambrosia confertiflora | 0–1 | – | ||
| southern Sierra pincushion | CHAL | Chaenactis alpigena | 0–1 | – | ||
| whitemargin sandmat | CHAL11 | Chamaesyce albomarginata | 0–1 | – | ||
| shrubby deervetch | LORI3 | Lotus rigidus | 0–1 | – | ||
| 4 | Annual Forbs | 17–118 | ||||
| common fiddleneck | AMMEI2 | Amsinckia menziesii var. intermedia | 0–11 | – | ||
| bristly fiddleneck | AMTE3 | Amsinckia tessellata | 0–11 | – | ||
| desert Indianwheat | PLOV | Plantago ovata | 0–11 | – | ||
| buckwheat | ERIOG | Eriogonum | 0–11 | – | ||
| Coulter's globemallow | SPCO2 | Sphaeralcea coulteri | 0–6 | – | ||
| western tansymustard | DEPI | Descurainia pinnata | 0–6 | – | ||
| cryptantha | CRYPT | Cryptantha | 0–3 | – | ||
| hairy prairie clover | DAMO | Dalea mollis | 0–1 | – | ||
| American wild carrot | DAPU3 | Daucus pusillus | 0–1 | – | ||
| carelessweed | AMPA | Amaranthus palmeri | 0–1 | – | ||
| touristplant | DIWI2 | Dimorphocarpa wislizeni | 0–1 | – | ||
| flatcrown buckwheat | ERDE6 | Eriogonum deflexum | 0–1 | – | ||
| miniature woollystar | ERDI2 | Eriastrum diffusum | 0–1 | – | ||
| erigenia | ERIGE | Erigenia | 0–1 | – | ||
| fringed amaranth | AMFI | Amaranthus fimbriatus | 0–1 | – | ||
| milkvetch | ASTRA | Astragalus | 0–1 | – | ||
| wheelscale saltbush | ATEL | Atriplex elegans | 0–1 | – | ||
| wheelscale saltbush | ATELF | Atriplex elegans var. fasciculata | 0–1 | – | ||
| Wright's saltbush | ATWR | Atriplex wrightii | 0–1 | – | ||
| Coulter's spiderling | BOCO2 | Boerhavia coulteri | 0–1 | – | ||
| hoary bowlesia | BOIN3 | Bowlesia incana | 0–1 | – | ||
| exserted Indian paintbrush | CAEXE | Castilleja exserta ssp. exserta | 0–1 | – | ||
| yellow tackstem | CAPA7 | Calycoseris parryi | 0–1 | – | ||
| white tackstem | CAWR | Calycoseris wrightii | 0–1 | – | ||
| brittle spineflower | CHBR | Chorizanthe brevicornu | 0–1 | – | ||
| aridland goosefoot | CHDE | Chenopodium desiccatum | 0–1 | – | ||
| hyssopleaf sandmat | CHHY3 | Chamaesyce hyssopifolia | 0–1 | – | ||
| devil's spineflower | CHRI | Chorizanthe rigida | 0–1 | – | ||
| Esteve's pincushion | CHST | Chaenactis stevioides | 0–1 | – | ||
| sand pygmyweed | CRCO34 | Crassula connata | 0–1 | – | ||
| woollyhead neststraw | STMI2 | Stylocline micropoides | 0–1 | – | ||
| sand fringepod | THCU | Thysanocarpus curvipes | 0–1 | – | ||
| cutleaf thelypody | THLA | Thelypodium laciniatum | 0–1 | – | ||
| woolly tidestromia | TILA2 | Tidestromia lanuginosa | 0–1 | – | ||
| doubleclaw | PRPA2 | Proboscidea parviflora | 0–1 | – | ||
| New Mexico plumeseed | RANE | Rafinesquia neomexicana | 0–1 | – | ||
| chia | SACO6 | Salvia columbariae | 0–1 | – | ||
| sleepy silene | SIAN2 | Silene antirrhina | 0–1 | – | ||
| common woolly sunflower | ERLA6 | Eriophyllum lanatum | 0–1 | – | ||
| Texas stork's bill | ERTE13 | Erodium texanum | 0–1 | – | ||
| California poppy | ESCAM | Eschscholzia californica ssp. mexicana | 0–1 | – | ||
| pygmy poppy | ESMI | Eschscholzia minutiflora | 0–1 | – | ||
| hairy desertsunflower | GECA2 | Geraea canescens | 0–1 | – | ||
| gilia | GILIA | Gilia | 0–1 | – | ||
| Arizona poppy | KAGR | Kallstroemia grandiflora | 0–1 | – | ||
| California goldfields | LACA7 | Lasthenia californica | 0–1 | – | ||
| Gordon's bladderpod | LEGO | Lesquerella gordonii | 0–1 | – | ||
| shaggyfruit pepperweed | LELA | Lepidium lasiocarpum | 0–1 | – | ||
| Bigelow's linanthus | LIBI2 | Linanthus bigelovii | 0–1 | – | ||
| coastal bird's-foot trefoil | LOSA | Lotus salsuginosus | 0–1 | – | ||
| Arizona lupine | LUAR4 | Lupinus arizonicus | 0–1 | – | ||
| Coulter's lupine | LUSP2 | Lupinus sparsiflorus | 0–1 | – | ||
| disc mayweed | MADI6 | Matricaria discoidea | 0–1 | – | ||
| blazingstar | MENTZ | Mentzelia | 0–1 | – | ||
| Nuttall's povertyweed | MONU | Monolepis nuttalliana | 0–1 | – | ||
| bristly nama | NAHI | Nama hispidum | 0–1 | – | ||
| glandular threadplant | NEGL | Nemacladus glanduliferus | 0–1 | – | ||
| lineleaf whitepuff | OLLI | Oligomeris linifolia | 0–1 | – | ||
| Florida pellitory | PAFL3 | Parietaria floridana | 0–1 | – | ||
| combseed | PECTO | Pectocarya | 0–1 | – | ||
| manybristle chinchweed | PEPA2 | Pectis papposa | 0–1 | – | ||
| phacelia | PHACE | Phacelia | 0–1 | – | ||
|
Shrub/Vine
|
||||||
| 5 | Dominant Shrubs | 118–235 | ||||
| creosote bush | LATR2 | Larrea tridentata | 118–235 | – | ||
| 6 | Dominant Half-Shrubs | 39–78 | ||||
| burrobush | AMDU2 | Ambrosia dumosa | 11–28 | – | ||
| triangle bur ragweed | AMDE4 | Ambrosia deltoidea | 11–22 | – | ||
| white ratany | KRGR | Krameria grayi | 6–17 | – | ||
| littleleaf ratany | KRER | Krameria erecta | 6–11 | – | ||
| 7 | Miscellaneous Shrubs | 3–8 | ||||
| whitethorn acacia | ACCO2 | Acacia constricta | 0–1 | – | ||
| cattle saltbush | ATPO | Atriplex polycarpa | 0–1 | – | ||
| crucifixion thorn | CAEM4 | Castela emoryi | 0–1 | – | ||
| ocotillo | FOSP2 | Fouquieria splendens | 0–1 | – | ||
| crown of thorns | KOSP | Koeberlinia spinosa | 0–1 | – | ||
| water jacket | LYAN | Lycium andersonii | 0–1 | – | ||
| Berlandier's wolfberry | LYBE | Lycium berlandieri | 0–1 | – | ||
| Arizona desert-thorn | LYEX | Lycium exsertum | 0–1 | – | ||
| desert ironwood | OLTE | Olneya tesota | 0–1 | – | ||
| yellow paloverde | PAMI5 | Parkinsonia microphylla | 0–1 | – | ||
| velvet mesquite | PRVE | Prosopis velutina | 0–1 | – | ||
| whitestem paperflower | PSCO2 | Psilostrophe cooperi | 0–1 | – | ||
| lotebush | ZIOB | Ziziphus obtusifolia | 0–1 | – | ||
| 8 | Succulents | 3–11 | ||||
| candy barrelcactus | FEWI | Ferocactus wislizeni | 0–1 | – | ||
| beavertail pricklypear | OPBA2 | Opuntia basilaris | 0–1 | – | ||
| nightblooming cereus | PEGR3 | Peniocereus greggii | 0–1 | – | ||
Interpretations
Animal community
This site produces no herbaceous forage for year round use. Shrubby species on the site are not palatable. In wet winters the production of cool season annuals can be very high and provide for a high carrying capacity of stocker cattle in the March-May grazing season.
Water developments will help some species of wildlife on this site. Cover, forage and diversity are lacking for the large desert mammals. This site is home to a variety of small burrowing mammals, reptiles and their predators.
Other information
T&E: Antilocapra Americana sonoriensis
(Sonoran pronghorn)
Tumamoca Macdougalii
(Tumamoc globe berry)
Leptonycteris curasoa yerbebuena
(Lesser long-nosed bat)
Supporting information
Type locality
| Location 1: Pima County, AZ | |
|---|---|
| Township/Range/Section | T10S R5E S26 |
| General legal description | Sells FO - Sif Oidak Dist., Tat Momoli Valley |
| Location 2: Pima County, AZ | |
| Township/Range/Section | T14S R6W S20 |
| General legal description | Tucson FO - Organ Pipe National Monument |
| Location 3: Maricopa County, AZ | |
| Township/Range/Section | T1S R7E S14 |
| General legal description | Chandler FO - General Motors Proving Grounds |
Contributors
Dan Robinett
Dan Robinett, J. Norris
Larry D. Ellicott
Steve Barker
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) | Dave Womack, Byron Lambeth, Dan Robinett, Emilio Carrillo |
|---|---|
| Contact for lead author | NRCS Tucson Area Office |
| Date | 03/02/2005 |
| Approved by | S. Cassady |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Rills are common and continuous in absence of high gravel cover. -
Presence of water flow patterns:
Water flow patterns are common, continuous and occupy 15-20% of area. -
Number and height of erosional pedestals or terracettes:
Accumulated pedestals on most perennial plants, not so much so in high gravel cover areas., 2-5 inches high. There are no pedestals on rock or gravel fragments and no terracettes are present. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
10-60% (low values in high gravel cover areas and/or El Nino years. -
Number of gullies and erosion associated with gullies:
none -
Extent of wind scoured, blowouts and/or depositional areas:
none -
Amount of litter movement (describe size and distance expected to travel):
Woody litter mostly stays under plant canopy, herbaceous litter can travel long distances. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface resistance to erosion is good under shrub canopies to moderate in interspaces due to crusts formed by raindrop impact. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
thin platy to weak granular; color is 7.5-10YR6/4 dry, 7.5-10YR4/4 moist, thickness to 3 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
cover estimated as: Canopy 10-15%; 65% shrubs, 5% trees and 30% succulents. Cover is well dispersed throughout site. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None -
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:
shrubs > subshrubs > trees > succulents > forbs = perennial grasses (Note: in El Nino years annual forbs and grasses are #1 in above ground weight)Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
0-50% canopy mortality. Some areas have 70-80% canopy mortality. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
200 lbs/ac unfavorable precipitation, 350 lbs/ac normal precipitation, 700 lbs/ac favorable precipitation -
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:
Sahara mustard, schismus, filaree -
Perennial plant reproductive capability:
Not impaired for shrubs, drought impaired for perennial grasses and forbs.
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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.
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