Natural Resources
Conservation Service
Ecological site R041XB206AZ
Limy Fan 8-12" p.z.
Last updated: 7/28/2020
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): 041X–Madrean Archipelago
AZ 41.2 – Chihuahuan – Sonoran Desert Shrubs
Elevations range from 2600 to 4000 feet and precipitation ranges from 8 to 12 inches per year. Vegetation includes mesquite, palo verde, catclaw acacia, soaptree yucca, creosotebush, whitethorn, staghorn cholla, desert saltbush, Mormon tea, burroweed, snakeweed, tobosa, black grama, threeawns, bush muhly, dropseed, and burrograss. 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.
Associated sites
| R041XB208AZ |
Limy Upland 8-12" p.z. |
|---|---|
| R041XB210AZ |
Loamy Upland 8-12" p.z. |
| R041XB213AZ |
Sandy Wash 8-12" p.z. |
Similar sites
| R040XA108AZ |
Limy Fan 10"-13" p.z. |
|---|---|
| R041XC320AZ |
Limy Fan 12-16" p.z. |
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) larrea tridentata |
| Herbaceous |
(1) muhlenbergia porteri |
Physiographic features
This site occurs in the lowest elevations of the Madrean Basin and Range province in southeastern Arizona. It occurs on fan terraces and alluvial fans.
Table 2. Representative physiographic features
| Landforms |
(1)
Fan piedmont
(2) Terrace (3) Alluvial fan |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 2,600 – 4,000 ft |
| Slope | 1 – 5% |
| Aspect | Aspect is not a significant factor |
Climatic features
Precipitation ranges from 8-12 inches annually. More than half falls during July-Sep in brief, but often heavy, thunderstorms. The rest of the moisture comes as light rain or snow that falls slowly for a day or more, but rarely lasts more than a day. May and June are normally the driest months. Humidity is generally very low.
Temperatures are mild throughout most of the year. Freezing temperatures are common at night Dec-Feb; brief 0 F may be observed some nights. During June, July & August, some days may exceed 100 F.
In years of average or greater winter precipitation, annual grasses and forbs occur abundantly in the interspaces.
Table 3. Representative climatic features
| Frost-free period (average) | 240 days |
|---|---|
| Freeze-free period (average) | |
| Precipitation total (average) |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
There are no water features associated with this site.
Soil features
These are deep, loamy soils; calcareous to the surface. Plant-soil moisture relationships are fair.
Soil series mapped to date on this site include: SSA-662 Safford area MU's CsB & GcB Gila, ThC Tres Hermanos; SSA-663 Gila-Duncan area MU's 9 Dona Ana, 29 43 & 45 Tres Hermanos; SSA-664 San Simon area MU's 14 & 15 Dona Ana, 40 Tres Hermanos; SSA-666 Cochise county Northwest part MU 1 Agustin & Kokan; SSA-671 Cochise county Douglas-Tombstone part MU's 36 Ugyp, 111 Ugyp, alluvial fans; SSA-675 San Carlos IR area MU's 1 Agustin, 5 Gila, 92 Agustin.
Table 4. Representative soil features
| Surface texture |
(1) Sandy loam (2) Fine sandy loam (3) Gravelly sandy loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained |
| Permeability class | Moderately rapid to moderate |
| Soil depth | 60 in |
| Surface fragment cover <=3" | 30% |
| Surface fragment cover >3" | 2% |
| Available water capacity (0-40in) |
5 – 7 in |
| Calcium carbonate equivalent (0-40in) |
5 – 30% |
| Electrical conductivity (0-40in) |
2 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
2 |
| Soil reaction (1:1 water) (0-40in) |
7.4 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
30% |
| Subsurface fragment volume >3" (Depth not specified) |
2% |
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 the 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
Figure 4. State and Transition Model, Limy Fan, 8"-12" p.z
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Click on state and transition labels to scroll to the respective text
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 1
Historical Climax Plant Community
Community 1.1
Historical Climax Plant Community
Figure 5. Limy Fan 8-12" pz
The potential plant community is a shrub-land dominated by creosotebush. Annual forbs and grasses are very important in the plant community on this site. Cryptogams (lichens, mosses) and blue-green algae are also important in the plant communities on this site. With continuous heavy grazing, bush muhly is removed from the plant community and creosotebush increases. Areas of this site mapped in alluvial fan positions are very susceptible to rill and gully erosion.
Figure 6. 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 | 150 | 250 |
| Grass/Grasslike | 10 | 30 | 170 |
| Forb | 1 | 20 | 110 |
| Total | 81 | 200 | 530 |
Table 6. Soil surface cover
| Tree basal cover | 0% |
|---|---|
| Shrub/vine/liana basal cover | 1% |
| Grass/grasslike basal cover | 0-2% |
| Forb basal cover | 0-2% |
| Non-vascular plants | 0% |
| Biological crusts | 5-15% |
| Litter | 5-60% |
| Surface fragments >0.25" and <=3" | 0-15% |
| Surface fragments >3" | 0-5% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 20-90% |
Table 7. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | 0-1% | 0-20% | 0-20% |
| >0.5 <= 1 | – | 0-1% | 0-20% | 0-10% |
| >1 <= 2 | – | 1-5% | – | 0-5% |
| >2 <= 4.5 | – | 5-10% | – | – |
| >4.5 <= 13 | – | – | – | – |
| >13 <= 40 | – | – | – | – |
| >40 <= 80 | – | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
State 2
Annuals
Community 2.1
Annuals
This state occurs where the plant community is dominated by native and non-native annual forbs and grasses. The causes can include repeated burning, which removes the native shrub cover (creosote), and cultivation for irrigation and subsequent abandonment.
State 3
Shrubs, exotic annuals
Community 3.1
Shrubs, exotic annuals
This state occurs where the creosote cover is still intact but the herbaceous layer of the plant community is dominated by non-native annuals. These can include, filaree, mediterranean grass, Sahara mustard, malta starthistle and red brome.
Transition T1A
State 1 to 2
Usually results from clearing for irrigated agriculture and subsequent abandonment. Seed source for native shrubs is no longer present.
Transition T1B
State 1 to 3
Introduction of a seed source of non-natives. Possible competition of exotics with native species of forbs or grasses.
Restoration pathway R2A
State 2 to 1
Unknown. Possible seeding of creosote bush and white-thorn acacia with weed control.
Restoration pathway R3A
State 3 to 1
Unknown
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 | Dominant perennial grasses | 10–60 | ||||
| bush muhly | MUPO2 | Muhlenbergia porteri | 10–40 | – | ||
| whiplash pappusgrass | PAVA2 | Pappophorum vaginatum | 0–40 | – | ||
| false Rhodes grass | TRCR9 | Trichloris crinita | 0–20 | – | ||
| Parish's threeawn | ARPUP5 | Aristida purpurea var. parishii | 0–20 | – | ||
| spike dropseed | SPCO4 | Sporobolus contractus | 0–10 | – | ||
| 2 | Misc. perennial grasses | 0–10 | ||||
| purple threeawn | ARPU9 | Aristida purpurea | 0–10 | – | ||
| spidergrass | ARTE3 | Aristida ternipes | 0–10 | – | ||
| tobosagrass | PLMU3 | Pleuraphis mutica | 0–10 | – | ||
| spidergrass | ARTEG | Aristida ternipes var. gentilis | 0–5 | – | ||
| low woollygrass | DAPU7 | Dasyochloa pulchella | 0–2 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 0–2 | – | ||
| mesa dropseed | SPFL2 | Sporobolus flexuosus | 0–2 | – | ||
| poverty threeawn | ARDI5 | Aristida divaricata | 0–2 | – | ||
| Havard's threeawn | ARHA3 | Aristida havardii | 0–2 | – | ||
| Arizona cottontop | DICA8 | Digitaria californica | 0–1 | – | ||
| nineawn pappusgrass | ENDE | Enneapogon desvauxii | 0–1 | – | ||
| plains bristlegrass | SEVU2 | Setaria vulpiseta | 0–1 | – | ||
| 3 | Annual grasses | 0–100 | ||||
| needle grama | BOAR | Bouteloua aristidoides | 0–50 | – | ||
| sixweeks grama | BOBA2 | Bouteloua barbata | 0–50 | – | ||
| Rothrock's grama | BORO2 | Bouteloua rothrockii | 0–20 | – | ||
| desert lovegrass | ERPEM | Eragrostis pectinacea var. miserrima | 0–20 | – | ||
| tufted lovegrass | ERPEP2 | Eragrostis pectinacea var. pectinacea | 0–20 | – | ||
| Arizona signalgrass | URAR | Urochloa arizonica | 0–20 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 0–20 | – | ||
| sixweeks threeawn | ARAD | Aristida adscensionis | 0–20 | – | ||
| prairie threeawn | AROL | Aristida oligantha | 0–20 | – | ||
| mucronate sprangeltop | LEPAB | Leptochloa panicea ssp. brachiata | 0–20 | – | ||
| Bigelow's bluegrass | POBI | Poa bigelovii | 0–10 | – | ||
| Mexican sprangletop | LEFUU | Leptochloa fusca ssp. uninervia | 0–10 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 0–5 | – | ||
| canyon cupgrass | ERLE7 | Eriochloa lemmonii | 0–5 | – | ||
| delicate muhly | MUFR | Muhlenbergia fragilis | 0–2 | – | ||
| littleseed muhly | MUMI | Muhlenbergia microsperma | 0–2 | – | ||
|
Forb
|
||||||
| 4 | Perennial forbs | 1–10 | ||||
| dwarf desertpeony | ACNA2 | Acourtia nana | 0–10 | – | ||
| trailing windmills | ALIN | Allionia incarnata | 0–5 | – | ||
| lacy tansyaster | MAPIP4 | Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida | 0–5 | – | ||
| desert globemallow | SPAM2 | Sphaeralcea ambigua | 0–5 | – | ||
| weakleaf bur ragweed | AMCO3 | Ambrosia confertiflora | 0–2 | – | ||
| hairyseed bahia | BAAB | Bahia absinthifolia | 0–1 | – | ||
| desert marigold | BAMU | Baileya multiradiata | 0–1 | – | ||
| whitemargin sandmat | CHAL11 | Chamaesyce albomarginata | 0–1 | – | ||
| Coues' cassia | SECO10 | Senna covesii | 0–1 | – | ||
| 5 | Annual forbs | 0–100 | ||||
| bristly fiddleneck | AMTE3 | Amsinckia tessellata | 0–25 | – | ||
| Coulter's spiderling | BOCO2 | Boerhavia coulteri | 0–20 | – | ||
| Esteve's pincushion | CHST | Chaenactis stevioides | 0–20 | – | ||
| flatcrown buckwheat | ERDE6 | Eriogonum deflexum | 0–20 | – | ||
| California poppy | ESCAM | Eschscholzia californica ssp. mexicana | 0–20 | – | ||
| Gordon's bladderpod | LEGO | Lesquerella gordonii | 0–20 | – | ||
| tanseyleaf tansyaster | MATA2 | Machaeranthera tanacetifolia | 0–20 | – | ||
| combseed | PECTO | Pectocarya | 0–20 | – | ||
| woolly tidestromia | TILA2 | Tidestromia lanuginosa | 0–20 | – | ||
| wheelscale saltbush | ATEL | Atriplex elegans | 0–15 | – | ||
| milkvetch | ASTRA | Astragalus | 0–10 | – | ||
| carelessweed | AMPA | Amaranthus palmeri | 0–10 | – | ||
| manybristle chinchweed | PEPA2 | Pectis papposa | 0–10 | – | ||
| desert Indianwheat | PLOV | Plantago ovata | 0–10 | – | ||
| shaggyfruit pepperweed | LELA | Lepidium lasiocarpum | 0–10 | – | ||
| miniature woollystar | ERDI2 | Eriastrum diffusum | 0–10 | – | ||
| cryptantha | CRYPT | Cryptantha | 0–10 | – | ||
| American wild carrot | DAPU3 | Daucus pusillus | 0–10 | – | ||
| western tansymustard | DEPI | Descurainia pinnata | 0–10 | – | ||
| Coulter's globemallow | SPCO2 | Sphaeralcea coulteri | 0–10 | – | ||
| intermediate pepperweed | LEVIM | Lepidium virginicum var. medium | 0–5 | – | ||
| coastal bird's-foot trefoil | LOSAB | Lotus salsuginosus var. brevivexillus | 0–5 | – | ||
| New Mexico plumeseed | RANE | Rafinesquia neomexicana | 0–5 | – | ||
| sleepy silene | SIAN2 | Silene antirrhina | 0–5 | – | ||
| phacelia | PHACE | Phacelia | 0–5 | – | ||
| Arizona popcornflower | PLAR | Plagiobothrys arizonicus | 0–5 | – | ||
| Nuttall's povertyweed | MONU | Monolepis nuttalliana | 0–5 | – | ||
| slender goldenweed | MAGR10 | Machaeranthera gracilis | 0–5 | – | ||
| exserted Indian paintbrush | CAEXE | Castilleja exserta ssp. exserta | 0–5 | – | ||
| yellow tackstem | CAPA7 | Calycoseris parryi | 0–5 | – | ||
| white tackstem | CAWR | Calycoseris wrightii | 0–5 | – | ||
| brittle spineflower | CHBR | Chorizanthe brevicornu | 0–2 | – | ||
| hyssopleaf sandmat | CHHY3 | Chamaesyce hyssopifolia | 0–2 | – | ||
| fringed redmaids | CACI2 | Calandrinia ciliata | 0–2 | – | ||
| desert evening primrose | OEPR | Oenothera primiveris | 0–2 | – | ||
| Florida pellitory | PAFL3 | Parietaria floridana | 0–2 | – | ||
| green carpetweed | MOVE | Mollugo verticillata | 0–2 | – | ||
| Coulter's lupine | LUSP2 | Lupinus sparsiflorus | 0–2 | – | ||
| hairy desertsunflower | GECA2 | Geraea canescens | 0–2 | – | ||
| star gilia | GIST | Gilia stellata | 0–2 | – | ||
| Arizona poppy | KAGR | Kallstroemia grandiflora | 0–2 | – | ||
| hairy prairie clover | DAMO | Dalea mollis | 0–2 | – | ||
| sorrel buckwheat | ERPO4 | Eriogonum polycladon | 0–2 | – | ||
| Texas stork's bill | ERTE13 | Erodium texanum | 0–2 | – | ||
| woollyhead neststraw | STMI2 | Stylocline micropoides | 0–2 | – | ||
| common woolly sunflower | ERLA6 | Eriophyllum lanatum | 0–1 | – | ||
| Mexican fireplant | EUHE4 | Euphorbia heterophylla | 0–1 | – | ||
| bristly nama | NAHI | Nama hispidum | 0–1 | – | ||
| glandular threadplant | NEGL | Nemacladus glanduliferus | 0–1 | – | ||
| doubleclaw | PRPA2 | Proboscidea parviflora | 0–1 | – | ||
| hoary bowlesia | BOIN3 | Bowlesia incana | 0–1 | – | ||
|
Shrub/Vine
|
||||||
| 6 | Dominant shrub | 70–200 | ||||
| creosote bush | LATRT | Larrea tridentata var. tridentata | 70–200 | – | ||
| 7 | Miscellaneous shrubs | 0–15 | ||||
| whitethorn acacia | ACCO2 | Acacia constricta | 0–10 | – | ||
| cattle saltbush | ATPO | Atriplex polycarpa | 0–10 | – | ||
| longleaf jointfir | EPTR | Ephedra trifurca | 0–5 | – | ||
| burrobush | AMDU2 | Ambrosia dumosa | 0–2 | – | ||
| fourwing saltbush | ATCA2 | Atriplex canescens | 0–2 | – | ||
| mound saltbush | ATOB | Atriplex obovata | 0–2 | – | ||
| burroweed | ISTE2 | Isocoma tenuisecta | 0–1 | – | ||
| water jacket | LYAN | Lycium andersonii | 0–1 | – | ||
| pale desert-thorn | LYPA | Lycium pallidum | 0–1 | – | ||
| western honey mesquite | PRGLT | Prosopis glandulosa var. torreyana | 0–1 | – | ||
| soaptree yucca | YUEL | Yucca elata | 0–1 | – | ||
| lotebush | ZIOB | Ziziphus obtusifolia | 0–1 | – | ||
| 8 | Half shrubs | 0–20 | ||||
| threadleaf snakeweed | GUMI | Gutierrezia microcephala | 0–10 | – | ||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 0–10 | – | ||
| whitestem paperflower | PSCO2 | Psilostrophe cooperi | 0–10 | – | ||
| desert zinnia | ZIAC | Zinnia acerosa | 0–10 | – | ||
| littleleaf ratany | KRER | Krameria erecta | 0–5 | – | ||
| rayless goldenhead | ACSP | Acamptopappus sphaerocephalus | 0–2 | – | ||
| 9 | Succulents | 0–15 | ||||
| devil's cholla | GRKU | Grusonia kunzei | 0–3 | – | ||
| Christmas cactus | CYLE8 | Cylindropuntia leptocaulis | 0–2 | – | ||
| tulip pricklypear | OPPH | Opuntia phaeacantha | 0–2 | – | ||
| nightblooming cereus | PEGR3 | Peniocereus greggii | 0–1 | – | ||
| walkingstick cactus | CYSP8 | Cylindropuntia spinosior | 0–1 | – | ||
| Engelmann's hedgehog cactus | ECEN | Echinocereus engelmannii | 0–1 | – | ||
| candy barrelcactus | FEWI | Ferocactus wislizeni | 0–1 | – | ||
| cactus apple | OPEN3 | Opuntia engelmannii | 0–1 | – | ||
| buck-horn cholla | CYAC8 | Cylindropuntia acanthocarpa | 0–1 | – | ||
Interpretations
Animal community
This site is more suitable for seasonal rather than year-long use as most of the forage produced consists of either winter or summer annual grasses and forbs in average or above average years. Perennial forage species can grow year round with available moisture but are in limited amounts in the plant community. Forage production on the site in dry years is very low. Bush muhly is shrub-like in character and plants supported by creosotebush should be utilized as browse plants.
Vegetative cover and forage diversity are lacking for large desert mammals on this site. It is home mainly to small, burrowing animals and rabbits.
Hydrological functions
These soils are medium textured and usually poor producers of runoff.
Recreational uses
Hunting, horseback riding, hiking, four wheeling.
Supporting information
Contributors
Dan Robinett
Larry D. Ellicott
Approval
Scott Woodall, 7/28/2020
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) | Wilma Renken, Dan Robinett, Larry Humphrey, Gwen Dominguez, Emilio Carrillo |
|---|---|
| Contact for lead author | Tucson MLRA Soil Survey Office |
| Date | 08/08/2013 |
| Approved by | Scott Woodall |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None -
Presence of water flow patterns:
Water flow paths occupy less than 30-40% of the surface area. Flow paths are poorly defined and dominated by limited sheet flow among the hummocks among creosote. -
Number and height of erosional pedestals or terracettes:
Pedestals are common on all longer lived grasses (bush muhly) and subshrubs (zinnia) and are from 1-2 inches in height. Pedestals on creosote bush are from 4-8 inches tall and symmetrical. They are well stabilized and most have rodent activity. Terracettes are uncommon on the site but when they occur they are large (approx. 3-5’ diam x 4-8” ht) and bridged by the mounds of creosote bush. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare soil is 50-70%, gravel ranges from 7-10% and basal cover of live perennial grasses is 1%. Bare areas are 4-8 feet in diameter, well dispersed and generally connected. -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
Possible wind capture of dust around the bases of creosote bush. No wind scour. Deposition under creosote bush has symmetrical mounds. -
Amount of litter movement (describe size and distance expected to travel):
Fine and coarse litter size classes are moving short distances (1-2 feet) from water in open spaces and concentrating in dams. Under large shrubs, all litter classes are staying in place. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Values from soil slake test ratings were 2-4s under canopy and 1-2’s from open spaces. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Shrub canopy cover is 25-30%, annual forb and grass canopy is <15%, and perennial grass canopy is <5%. Perennial grasses are largely confined within creosote bush mounds. Shrubs are evenly distributed. Shrub canopy cover and soil texture (sandyloam) allow infiltration and limit run-off. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
None present, average depth of penetration from an ARS field penetrometer with a 2.2 kg. sliding hammer is 12.8 cm. -
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:
large shrubsSub-dominant:
annual grass= annual forbs> perennial grasses = sub shrubs >> succulentsOther:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Plant mortality is affected by recent droughty weather patterns; 10% mortality on perennial grasses and 30% on sub-shrubs. Some creosote canopy died back. Large crown-of-thorn shrubs have about 20% mortality. -
Average percent litter cover (%) and depth ( in):
Litter is absent from water flow patterns and bare areas. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
80 lbs/ac. in a below average year; 200 lbs/ac. in an average year; 530 lbs/ac. in an above average year. -
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:
Tumbleweed, Lehmann lovegrass in wet years -
Perennial plant reproductive capability:
Not impaired for any perennial species.
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