Natural Resources
Conservation Service
Ecological site R040XC318AZ
Sandy Wash 3"-7" p.z.
Accessed: 11/21/2024
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 40.3 – Colorado Sonoran Desert
Elevations range from 300 to 1200 feet and precipitation averages 3 to 7 inches per year. Vegetation includes creosotebush, white bursage, brittlebush, Mormon tea, teddybear cholla, elephant tree, smoke tree, ocotillo, 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.
Table 1. Dominant plant species
| Tree |
(1) Parkinsonia microphylla |
|---|---|
| Shrub |
(1) Acacia greggii |
| Herbaceous |
(1) Pleuraphis rigida |
Physiographic features
This site occurs in a bottom position. It benefits significantly from run-in moisture from adjacent areas. The soils may suffer from excessive loss from runoff. It occurs as floodplains, low terraces, alluvial fans and drainageways.
Table 2. Representative physiographic features
| Landforms |
(1)
Flood plain
(2) Terrace (3) Alluvial fan |
|---|---|
| Elevation | 75 – 1,000 ft |
| Slope | 5% |
Climatic features
Precipitation in this common resource area ranges from 3-7 inches yearly. Despite historical averages in rainfall amounts, 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 44% at Gila Bend and 65% at Mohawk. Winter-Summer rainfall ratios are 40-60%. Summer rains fall July-September, originate in the Gulf of Mexico and are convective, usually brief intense thunderstorms. Summer thunderstorms usually form over the mountains in the afternoon and spread to the valleys and plains in the evening. The intensity of this precipitation is moderate to heavy, but rarely lasts more than half an hour. Many times these storms produce little more than gusty winds and light showers. Cool season moisture tends to be frontal, originate in the Pacific and Gulf of California and falls in widespread storms with long duration and low intensity. Snow is very rare and falls normally only in the higher mountains.
Mean temperatures for the hottest month (Jul) is 93 F; the coldest month (Jan) is 53 F. Extreme temperatures of 125 F and 10 F have been recorded. Long periods with little or no effective moisture occur frequently.
The winter-spring precipitation is the most dependable on the site. Perennial grasses, though classed as warm season growers, grow actively year-round when moisture is available. Shrubs and trees generally respond to seasonal moisture. The two rainy periods bring about their respective production of either winter or summer annual grasses and forbs.
Table 3. Representative climatic features
| Frost-free period (average) | 363 days |
|---|---|
| Freeze-free period (average) | 0 days |
| Precipitation total (average) | 7 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
Soils that are grouped together in this range site are deep to bedrock or other plant root restricting layers. The surface soil depth ranges from 6-8 inches with textures ranging from very gravelly loamy sand, loamy sand to silt loam. The underlying layers have a rapid permeability and hold all moisture the climate supplies. Soluble salt accumulations are low and pH ranges from 7.9-8.4. With good vegetative cover, infiltration rates are high. Stability against erosion processes is poor. Plant-soil moisture relationships are poor. Coarse fragments may be found throughout the soil In the Carrizo, it ranges from 35-85% coarse fragment. In the Lagunita, it ranges from 0-15% coarse fragments.
Soils mapped on this site include: in SSA-627 Southern Mohave county MU's Carrizo family-19 & 20, Carrizo-21; SSA-645 Aguila-Carefree area MU's Brios-11, Carrizo-4 & 11; SSA-649 Yuma-Wellton area MU's Carrizo-3, Lagunita-16 & 18, Torrifluvents-30; SSA-653 Gila Bend-Ajo area MU's Carrizo-67, Vint vfsl-63, Why Grfsl-66 & Why-67; SSA-656 Colorado River Indian Reservation area MU's Carrizo-5 & 17.
Table 4. Representative soil features
| Surface texture |
(1) Loamy sand (2) Sand (3) Sandy loam |
|---|---|
| Family particle size |
(1) Sandy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderately rapid to very rapid |
| Soil depth | 60 in |
| Surface fragment cover <=3" | 5 – 45% |
| Surface fragment cover >3" | 10% |
| Available water capacity (0-40in) |
1.8 – 7.2 in |
| Calcium carbonate equivalent (0-40in) |
10% |
| Electrical conductivity (0-40in) |
1 mmhos/cm |
| 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) |
5 – 45% |
| Subsurface fragment volume >3" (Depth not specified) |
10% |
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 fire, grazing, 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 amount shown for each group. Divide the resulting total by the total normal year production shown in the plant community description. If the 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.
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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 plant community is a mixture of perennial grasses and forbs, desert trees and shrubs, and annual grasses and forbs. The active washy areas in the site have little vegetation except burrobush and annual grasses and forbs. Continuous grazing use and the absence of natural fires have led to woody plant invasion. These areas are extremely sensitive and when plant cover has been reduced, the extra water concentrated on the site causes accelerated erosion and channel cutting. As a result, less and less of the original overflow areas still get flooded.
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 | 520 | 688 | 855 |
| Shrub/Vine | 280 | 370 | 460 |
| Forb | 140 | 210 | 280 |
| Tree | 10 | 45 | 80 |
| Total | 950 | 1313 | 1675 |
Figure 5. Plant community growth curve (percent production by month). AZ4041, 40.3 3-7" p.z. all sites. Most growth occurs in the winter to early spring, plants are dormant May through October..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 5 | 20 | 40 | 25 | 0 | 0 | 0 | 0 | 0 | 0 | 5 | 5 |
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 | 350–500 | ||||
| big galleta | PLRI3 | Pleuraphis rigida | 210–280 | – | ||
| bush muhly | MUPO2 | Muhlenbergia porteri | 140–210 | – | ||
| Arizona cottontop | DICA8 | Digitaria californica | 14–70 | – | ||
| 1 | Threeawn Group | 140–210 | ||||
| blue threeawn | ARPUN | Aristida purpurea var. nealleyi | 15–21 | – | ||
| Parish's threeawn | ARPUP5 | Aristida purpurea var. parishii | 15–21 | – | ||
| Wright's threeawn | ARPUW | Aristida purpurea var. wrightii | 15–21 | – | ||
| spidergrass | ARTE3 | Aristida ternipes | 15–21 | – | ||
| spidergrass | ARTEG | Aristida ternipes var. gentilis | 15–21 | – | ||
| Santa Rita threeawn | ARCAG | Aristida californica var. glabrata | 15–21 | – | ||
| poverty threeawn | ARDI5 | Aristida divaricata | 15–21 | – | ||
| purple threeawn | ARPU9 | Aristida purpurea | 15–21 | – | ||
| Fendler's threeawn | ARPUF | Aristida purpurea var. fendleriana | 15–21 | – | ||
| 2 | Misc. Perennial Grasses | 15–75 | ||||
| spike dropseed | SPCO4 | Sporobolus contractus | 4–20 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 4–20 | – | ||
| mesa dropseed | SPFL2 | Sporobolus flexuosus | 4–20 | – | ||
| slim tridens | TRMU | Tridens muticus | 4–20 | – | ||
| 3 | Annual Grasses | 15–70 | ||||
| sixweeks threeawn | ARAD | Aristida adscensionis | 0–14 | – | ||
| needle grama | BOAR | Bouteloua aristidoides | 0–14 | – | ||
| sixweeks grama | BOBA2 | Bouteloua barbata | 0–14 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 0–14 | – | ||
| low woollygrass | DAPU7 | Dasyochloa pulchella | 5–14 | – | ||
| Devils Canyon muhly | MUAP | Muhlenbergia appressa | 0–14 | – | ||
| littleseed muhly | MUMI | Muhlenbergia microsperma | 0–14 | – | ||
| Bigelow's bluegrass | POBI | Poa bigelovii | 5–14 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 5–14 | – | ||
|
Forb
|
||||||
| 4 | Misc. Forbs | 70–140 | ||||
| Santa Rita threeawn | ARCAG | Aristida californica var. glabrata | 14–21 | – | ||
| poverty threeawn | ARDI5 | Aristida divaricata | 14–21 | – | ||
| purple threeawn | ARPU9 | Aristida purpurea | 14–21 | – | ||
| Fendler's threeawn | ARPUF | Aristida purpurea var. fendleriana | 14–21 | – | ||
| blue threeawn | ARPUN | Aristida purpurea var. nealleyi | 14–21 | – | ||
| Parish's threeawn | ARPUP5 | Aristida purpurea var. parishii | 14–21 | – | ||
| spidergrass | ARTE3 | Aristida ternipes | 14–21 | – | ||
| spidergrass | ARTEG | Aristida ternipes var. gentilis | 14–21 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 0–15 | – | ||
| needle grama | BOAR | Bouteloua aristidoides | 0–10 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 0–10 | – | ||
| Devils Canyon muhly | MUAP | Muhlenbergia appressa | 0–10 | – | ||
| littleseed muhly | MUMI | Muhlenbergia microsperma | 0–10 | – | ||
| Bigelow's bluegrass | POBI | Poa bigelovii | 0–10 | – | ||
| spike dropseed | SPCO4 | Sporobolus contractus | 0–10 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 0–10 | – | ||
| mesa dropseed | SPFL2 | Sporobolus flexuosus | 0–10 | – | ||
| sixweeks threeawn | ARAD | Aristida adscensionis | 0–10 | – | ||
| pelotazo | ABIN | Abutilon incanum | 1–7 | – | ||
| Indian mallow | ABUTI | Abutilon | 2–7 | – | ||
| brownfoot | ACWR5 | Acourtia wrightii | 1–7 | – | ||
| trailing windmills | ALIN | Allionia incarnata | 1–7 | – | ||
| weakleaf bur ragweed | AMCO3 | Ambrosia confertiflora | 1–7 | – | ||
| carelessweed | AMPA | Amaranthus palmeri | 1–7 | – | ||
| smallflowered milkvetch | ASNU4 | Astragalus nuttallianus | 1–7 | – | ||
| milkvetch | ASTRA | Astragalus | 2–7 | – | ||
| desert marigold | BAMU | Baileya multiradiata | 1–7 | – | ||
| fleabane | ERIGE2 | Erigeron | 2–7 | – | ||
| pink velvetmallow | HOAL | Horsfordia alata | 1–7 | – | ||
| Arizona poppy | KAGR | Kallstroemia grandiflora | 1–7 | – | ||
| Coulter's lupine | LUSP2 | Lupinus sparsiflorus | 1–7 | – | ||
| wishbone-bush | MILAV | Mirabilis laevis var. villosa | 1–7 | – | ||
| monkeyflower | MIMUL | Mimulus | 2–7 | – | ||
| Bostock's minerslettuce | MOBO | Montia bostockii | 1–7 | – | ||
| bristly nama | NAHI | Nama hispidum | 1–7 | – | ||
| desert tobacco | NIOBO | Nicotiana obtusifolia var. obtusifolia | 1–7 | – | ||
| evening primrose | OENOT | Oenothera | 2–7 | – | ||
| lineleaf whitepuff | OLLI | Oligomeris linifolia | 1–7 | – | ||
| combseed | PECTO | Pectocarya | 2–7 | – | ||
| Emory's rockdaisy | PEEM | Perityle emoryi | 1–7 | – | ||
| manybristle chinchweed | PEPA2 | Pectis papposa | 1–7 | – | ||
| desert Indianwheat | PLOV | Plantago ovata | 1–7 | – | ||
| New Mexico plumeseed | RANE | Rafinesquia neomexicana | 1–7 | – | ||
| sleepy silene | SIAN2 | Silene antirrhina | 1–7 | – | ||
| desert globemallow | SPAM2 | Sphaeralcea ambigua | 1–7 | – | ||
| Coulter's globemallow | SPCO2 | Sphaeralcea coulteri | 1–7 | – | ||
| globemallow | SPHAE | Sphaeralcea | 2–7 | – | ||
| woolly tidestromia | TILA2 | Tidestromia lanuginosa | 1–7 | – | ||
| 5 | More Forbs | 70–140 | ||||
| Texas fluffgrass | TRTE2 | Tridens texanus | 7–14 | – | ||
| western tansymustard | DEPI | Descurainia pinnata | 2–10 | – | ||
| bluedicks | DICA14 | Dichelostemma capitatum | 1–7 | – | ||
| touristplant | DIWI2 | Dimorphocarpa wislizeni | 1–7 | – | ||
| fetid marigold | DYPA | Dyssodia papposa | 1–7 | – | ||
| whisperingbells | EMPE | Emmenanthe penduliflora | 1–7 | – | ||
| miniature woollystar | ERDI2 | Eriastrum diffusum | 1–7 | – | ||
| desert trumpet | ERIN4 | Eriogonum inflatum | 1–7 | – | ||
| buckwheat | ERIOG | Eriogonum | 2–7 | – | ||
| desert poppy | ESGL | Eschscholzia glyptosperma | 1–7 | – | ||
| pygmy poppy | ESMI | Eschscholzia minutiflora | 1–7 | – | ||
| hideseed | EUCRY | Eucrypta | 2–7 | – | ||
| spurge | EUPHO | Euphorbia | 2–7 | – | ||
| hairy desertsunflower | GECA2 | Geraea canescens | 1–7 | – | ||
| gilia | GILIA | Gilia | 2–7 | – | ||
| Gordon's bladderpod | LEGO | Lesquerella gordonii | 1–7 | – | ||
| shaggyfruit pepperweed | LELA | Lepidium lasiocarpum | 1–7 | – | ||
| trefoil | LOTUS | Lotus | 2–7 | – | ||
| Gila manroot | MAGI | Marah gilensis | 1–7 | – | ||
| Parry's false prairie-clover | MAPA7 | Marina parryi | 1–7 | – | ||
| blazingstar | MENTZ | Mentzelia | 2–7 | – | ||
| Florida pellitory | PAFL3 | Parietaria floridana | 1–7 | – | ||
| phacelia | PHACE | Phacelia | 2–7 | – | ||
| doubleclaw | PRPA2 | Proboscidea parviflora | 1–7 | – | ||
| canaigre dock | RUHY | Rumex hymenosepalus | 1–7 | – | ||
| woollyhead neststraw | STMI2 | Stylocline micropoides | 1–7 | – | ||
| brownplume wirelettuce | STPA4 | Stephanomeria pauciflora | 1–7 | – | ||
| desert sand verbena | ABVI | Abronia villosa | 1–7 | – | ||
| common fiddleneck | AMMEI2 | Amsinckia menziesii var. intermedia | 1–7 | – | ||
| narrowleaf silverbush | ARLA12 | Argythamnia lanceolata | 1–7 | – | ||
| New Mexico silverbush | ARNE2 | Argythamnia neomexicana | 1–7 | – | ||
| whitestem milkweed | ASAL | Asclepias albicans | 1–7 | – | ||
| milkweed | ASCLE | Asclepias | 2–7 | – | ||
| rush milkweed | ASSU | Asclepias subulata | 1–7 | – | ||
| spiderling | BOERH2 | Boerhavia | 2–7 | – | ||
| hoary bowlesia | BOIN3 | Bowlesia incana | 1–7 | – | ||
| exserted Indian paintbrush | CAEXE | Castilleja exserta ssp. exserta | 1–7 | – | ||
| goosefoot | CHENO | Chenopodium | 2–7 | – | ||
| New Mexico thistle | CINE | Cirsium neomexicanum | 1–7 | – | ||
| sand pygmyweed | CRCOC | Crassula connata var. connata | 1–7 | – | ||
| cryptantha | CRYPT | Cryptantha | 2–7 | – | ||
| fingerleaf gourd | CUDI | Cucurbita digitata | 1–7 | – | ||
| Missouri gourd | CUFO | Cucurbita foetidissima | 1–7 | – | ||
| desert thorn-apple | DADI2 | Datura discolor | 1–7 | – | ||
| hairy prairie clover | DAMO | Dalea mollis | 1–7 | – | ||
| sacred thorn-apple | DAWR2 | Datura wrightii | 1–7 | – | ||
|
Shrub/Vine
|
||||||
| 6 | Dominant Shrubs | 200–250 | ||||
| whitethorn acacia | ACCO2 | Acacia constricta | 50–85 | – | ||
| catclaw acacia | ACGR | Acacia greggii | 50–85 | – | ||
| desert-thorn | LYCIU | Lycium | 50–85 | – | ||
| desert ironwood | OLTE | Olneya tesota | 50–85 | – | ||
| sixweeks threeawn | ARAD | Aristida adscensionis | 1–7 | – | ||
| needle grama | BOAR | Bouteloua aristidoides | 1–7 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 1–7 | – | ||
| Devils Canyon muhly | MUAP | Muhlenbergia appressa | 1–7 | – | ||
| littleseed muhly | MUMI | Muhlenbergia microsperma | 1–7 | – | ||
| Bigelow's bluegrass | POBI | Poa bigelovii | 1–7 | – | ||
| scarlet globemallow | SPCO | Sphaeralcea coccinea | 1–7 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 1–7 | – | ||
| mesa dropseed | SPFL2 | Sporobolus flexuosus | 1–7 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 1–7 | – | ||
| 7 | Misc. Shrubs | 70–140 | ||||
| burrobush | AMDU2 | Ambrosia dumosa | 4–10 | – | ||
| Drummond's clematis | CLDR | Clematis drummondii | 4–10 | – | ||
| creosote bush | LATRT | Larrea tridentata var. tridentata | 4–10 | – | ||
| jojoba | SICH | Simmondsia chinensis | 2–5 | – | ||
| Hall's shrubby-spurge | TEHA | Tetracoccus hallii | 2–5 | – | ||
| honey mesquite | PRGL2 | Prosopis glandulosa | 2–5 | – | ||
| screwbean mesquite | PRPU | Prosopis pubescens | 2–5 | – | ||
| whitestem paperflower | PSCO2 | Psilostrophe cooperi | 2–5 | – | ||
| smoketree | PSSP3 | Psorothamnus spinosus | 2–5 | – | ||
| Mexican bladdersage | SAME | Salazaria mexicana | 2–5 | – | ||
| bitter snakewood | COGL | Condalia globosa | 2–5 | – | ||
| brittlebush | ENFA | Encelia farinosa | 2–5 | – | ||
| San Felipe dogweed | ADPO | Adenophyllum porophylloides | 2–5 | – | ||
| ambrosia leaf bur ragweed | AMAM2 | Ambrosia ambrosioides | 2–5 | – | ||
| triangle bur ragweed | AMDE4 | Ambrosia deltoidea | 2–5 | – | ||
| fringed twinevine | FUCYC | Funastrum cynanchoides ssp. cynanchoides | 2–5 | – | ||
| desert lavender | HYEM | Hyptis emoryi | 2–5 | – | ||
| singlewhorl burrobrush | HYMO | Hymenoclea monogyra | 2–5 | – | ||
| burrobrush | HYSA | Hymenoclea salsola | 2–5 | – | ||
| slender janusia | JAGR | Janusia gracilis | 2–5 | – | ||
| beloperone | JUCA8 | Justicia californica | 2–5 | – | ||
| crown of thorns | KOSP | Koeberlinia spinosa | 2–5 | – | ||
| narrowleaf silverbush | ARLA12 | Argythamnia lanceolata | 2–5 | – | ||
| fourwing saltbush | ATCA2 | Atriplex canescens | 0–5 | – | ||
| big saltbush | ATLE | Atriplex lentiformis | 2–5 | – | ||
| cattle saltbush | ATPO | Atriplex polycarpa | 1–5 | – | ||
| shortleaf baccharis | BABR | Baccharis brachyphylla | 2–5 | – | ||
| desertbroom | BASA2 | Baccharis sarothroides | 2–5 | – | ||
| sweetbush | BEJU | Bebbia juncea | 2–5 | – | ||
| Coulter's brickellbush | BRCO | Brickellia coulteri | 2–5 | – | ||
| crucifixion thorn | CAEM4 | Castela emoryi | 2–5 | – | ||
| American threefold | TRCA8 | Trixis californica | 2–5 | – | ||
| toothleaf goldeneye | VIDE3 | Viguiera dentata | 2–5 | – | ||
| lotebush | ZIOBO | Ziziphus obtusifolia var. obtusifolia | 2–5 | – | ||
| white ratany | KRGR | Krameria grayi | 0–4 | – | ||
| button brittlebush | ENFR | Encelia frutescens | 0–4 | – | ||
| longleaf jointfir | EPTR | Ephedra trifurca | 0–4 | – | ||
| Coulter's lyrepod | LYCO4 | Lyrocarpa coulteri | 0–4 | – | ||
| Douglas' ragwort | SEFLD | Senecio flaccidus var. douglasii | 0–3 | – | ||
| Hartweg's twinevine | FUCYH | Funastrum cynanchoides ssp. heterophyllum | 0–3 | – | ||
| 8 | Succulents | 14–70 | ||||
| saguaro | CAGI10 | Carnegiea gigantea | 2–10 | – | ||
| Arizona pencil cholla | CYAR14 | Cylindropuntia arbuscula | 2–10 | – | ||
| teddybear cholla | CYBI9 | Cylindropuntia bigelovii | 2–10 | – | ||
| Wiggins' cholla | CYEC3 | Cylindropuntia echinocarpa | 2–10 | – | ||
| Christmas cactus | CYLE8 | Cylindropuntia leptocaulis | 2–10 | – | ||
| branched pencil cholla | CYRA9 | Cylindropuntia ramosissima | 2–10 | – | ||
| ocotillo | FOSP2 | Fouquieria splendens | 2–10 | – | ||
|
Tree
|
||||||
| 9 | Trees | 10–80 | ||||
| blue paloverde | PAFL6 | Parkinsonia florida | 5–40 | – | ||
| yellow paloverde | PAMI5 | Parkinsonia microphylla | 5–40 | – | ||
Interpretations
Animal community
This site produces forage for year-round use and is easily traversed by stocker cattle, cows and calves. Because of water availability and ease of access, these sites are often overused. Where this site occurs as inclusions in larger areas of less productive sites (ile., limy uplands), these areas produce nearly all the forage and the entire area should be managed. Fencing, in managable units, of this site can be important in providing grazing control.
The variation in vegetation, coupled with forage production year-round and intermittent availability of water, this site is suitable habitat for a wide diversity of wildlife. Ogetn this site is the only one with suitable cover requirements for large desert mammals occuring in vast areas of upland sites with little or no cover. This site is also host to a variety of smaller animals, as well as birds and reptiles.
Recreational uses
This site is found throughout the alluvial fans and plains as sandy, tree-lined and gently sloping drainageways. The active washy areas of this site support little vegetation except for annual grasses and forbs and borrobush. Less active areas have an understory of desert trees with a diverse understory of forbs, grasses and shrubs. Very few days in the fall, winter or spring are too uncomfortable to enjoy outdoor activities. The afternoon heat of Jun-Aug restricts activities. This site is suitable for horseback riding, wildlife observation, hunting, hiking, picnicking and photography.
Supporting information
Type locality
| Location 1: La Paz County, AZ | |
|---|---|
| Township/Range/Section | T1N R12W S2 |
| General legal description | Eagle Tail Ranch |
Contributors
Larry D. Ellicott
Stephen Cassady
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:
None. -
Presence of water flow patterns:
Highly variable, function of upland overland flow input. -
Number and height of erosional pedestals or terracettes:
No accumulated or erosional pedestals on most perennial plants. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
15-40% -
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):
Highly variable, function of upland overland flow input. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
No slake test done. Expect ratings of 1-3 across site. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Weak Platy; color is 7.5-10YR6/4 dry, 7.5-10YR5/4 moist; thickness to 3 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Canopy 60-70%; 10-30% perennial grass, 40% shrubs, 10% subshrubs, 10% perennial forbs, 5-10% trees. 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:
perennial grass = trees > shrubs > sub shrubs > perennial forbs (note: this after several years of regional drought. Annual forbs and grasses may be greater than trees in El Nino years.)Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
20-30% canopy mortality of trees and shrubs; 90-100% mortality of perennial grasses. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
950 lbs/ac unfavorable precipitation; 1313 lbs/ac normal precipitation; 1675 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. -
Perennial plant reproductive capability:
Not impaired for shrubs and trees; 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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