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Ecological site R041XC304AZ
Clayey Upland
12-16" p.z.
Last updated: 7/21/2020
Accessed: 08/31/2026
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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.
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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 41.3 – Chihuahuan – Sonoran Semidesert Grasslands
Elevations range from 3200 to 5000 feet and precipitation ranges from 12 to 16 inches per year. Vegetation includes mesquite, catclaw acacia, netleaf hackberry, palo verde, false mesquite, range ratany, fourwing saltbush, tarbush, littleleaf sumac, sideoats grama, black grama, plains lovegrass, cane beardgrass, tobosa, vine mesquite, threeawns, Arizona cottontop and bush muhly. The soil temperature regime is thermic and the soil moisture regime is ustic 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
R041XC301AZ Basalt Hills 12-16" p.z.
R041XC302AZ Clayey Swale 12-16" p.z.
R041XC305AZ Clay Loam Upland 12-16" p.z.
Similar sites
R040XA104AZ Clayey Upland 10"-13" p.z.
R038XA102AZ Clayey Upland 12-16" p.z.
R041XB203AZ Clayey Upland 8-12" p.z.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) pleuraphis mutica
(2) panicum obtusumPhysiographic features
This site occurs in the middle elevations of the Madrean Basin and Range province in southeastern Arizona. It occurs on pediments, old fan terraces, basalt flows and mesa tops. It is always in an upland position.
Table 2. Representative physiographic features
Landforms (1) Fan piedmont
(2) Lava flow
(3) Plain
Flooding frequency None Ponding frequency None Elevation 3200 – 5000 ft Slope 1 – 15 % Aspect Aspect is not a significant factor Climatic features
Precipitation in this common resource area ranges from 12-16 inches yearly in the eastern part with elevations from 3600-5000 feet, and 13-17 inches in the western part where elevations are 3300-4500 feet. Winter-Summer rainfall ratios are 40-60% in the west and 30-70% in the east. Summer rains fall July-September, originate in the Gulf of Mexico and are convective, usually brief, intense thunderstorms. 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 rarely lasts more than one day. May and June are the driest months of the year. Humidity is generally very low.
Temperatures are mild. Freezing temperatures are common at night from December-April; however temperatures during the day are frequently above 50 F. Occasionally in December-February, brief 0 F temperatures may be experienced some nights. During June, July and August, some days may exceed 100 F.
Cool season plants start growth in early spring and mature in early summer. Warm season plants take advantage of summer rains and are growing and nutritious July-September. Warm season grasses may remain green throughout the year.Table 3 Representative climatic features
Frost-free period (average) 220 days Freeze-free period (average) Precipitation total (average) 20 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
There are no water features associated with this site.
Soil features
These are moderately deep to deep soils that have formed in clayey alluvium of basic igneous origin or from shale parent materials. They are very dark colored and have high shrink-swell potentials. Churning and cracking cause very uneven surfaces and has resulted in most of the gravels and cobbles being pushed to the surface. Plant-soil moisture relationships are good.
Soils mapped on this site include: SSA-661 Eastern Pinal & Southern Gila counties MU 39 Sontag; SSA-663 Gila--Duncan area MU 5 Bonita; SSA-664 San Simon area MU 8 Bonita; SSA-669 Pima county Eastern part MU 31 Graham; SSA-671 Cochise county Douglas-Tombstone part MU's 13 Bonita, 57 & 114 Outlaw, 61 Epitaph CbVCL, 114 Epitaph and Paramore.Table 4. Representative soil features
Parent material (1) Alluvium – basalt
Family particle size (1) Clayey
Drainage class Well drained Permeability class Moderately slow to slow Soil depth 30 – 60 in Surface fragment cover <=3" 5 – 20 % Surface fragment cover >3" 0 – 10 % Available water capacity
(0-40in)3.6 – 7.2 in Calcium carbonate equivalent
(0-40in)1 – 15 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 2 Soil reaction (1:1 water)
(0-40in)6.6 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 10 % Subsurface fragment volume >3"
(Depth not specified)0 – 5 % Ecological dynamics
This plant community is tobosa grassland with a canopy cover from 35 to 55%. It has a diverse flora of native annual forbs and grasses and minor amounts of shrubs. Periodic wildfires occurred, June thru August, and controlled shrubs encroaching from adjacent sites, and maintained tobosa in good vigor. When the tobosa canopy is reduced to less than 5% and its cover is patchy in distribution it will not be able to re-colonize large areas. Tobosa is a very poor seed producer, in the wild, and has almost no viable seed in the soil seed-bank. It is not known what influence the presence of non-native annuals has on the diversity of native species. Lehmann lovegrass is not adapted to this site and will not invade. Possible invasive and exotic weeds on this site include; yellow and malta starthistle, Russian and spotted knapweed; these may occur, especially where cultivated areas have been abandoned.
State and transition model
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Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Native Tobosa GrasslandCommunity 1.1
Historic Climax Plant CommunityThe potential plant community on this site is dominated by warm season perennial grasses, primarily tobosa and vine mesquite. Vine mesquite occurs in patches which are not evenly dispersed across the site.
With continuous grazing, patches develop which are dominated by annual forbs and grasses, with larger patches of almost pure tobosa. Palatable perennial grasses and forbs disappear. Mesquite does not appear to be able to dominate on this site, perhaps due to soil churning and cracking. Natural fire was important in the development of the potential plant community.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 480 875 1200 Forb 40 100 220 Shrub/Vine 0 25 100 Total 520 1000 1520 Table 6. Soil surface cover
Tree basal cover 0% Shrub/vine/liana basal cover 0% Grass/grasslike basal cover 10-20% Forb basal cover 0-0% Non-vascular plants 0-0% Biological crusts 0-10% Litter 30-60% Surface fragments >0.25" and <=3" 0-20% Surface fragments >3" 0-10% Bedrock 0% Water 0% Bare ground 20-30% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – – 0-5% 1-5% >0.5 <= 1 – 0-1% 2-15% 1-10% >1 <= 2 – 0-1% 35-55% 0-2% >2 <= 4.5 – 0-1% 0-5% – >4.5 <= 13 – – – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 5. Plant community growth curve (percent production by month). AZ4134 , 41.3 12-16" p.z. other sites. Growth begins in the spring, semi-dormancy occurs during the May through June drought, most growth occurs during the summer rains..
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 0 0 5 10 0 0 30 35 15 5 0 0 State 2
Annual forbs and grassesCommunity 2.1
Annual forbs and grasses
Figure 6. Clayey Upland 12-16" pz., annuals and shrubs
Tobosa canopy is reduced (less than 5%) due the interactions of drought, heavy grazing and / or fire. Some areas of this state have been created by cultivation for irrigated farming; with subsequent abandonment. Native and non-native annual species dominate. Tobosa canopy is gone or very low and patchy in distribution. Tobosa will not be able to re-colonize this state due to a lack of seed production and viable seeds in the soil seed-bank. Vertic soil properties maintain good soil tilth and good infiltration rates, when soils are dry. Plant production remains high, even with the lack of perennial grass cover, due to soil churning and cracking and good hydrologic relationships. Some mesquite, prickly pear, and other shrubs or succulents may be present.
State 3
Mesquite, native grassesCommunity 3.1
Mesquite, native grassesMesquite has invaded and occurs at canopy levels from 2 to 10%. Other shrubs may also occur like whitethorn acacia and prickly pear. Fire has been excluded for long periods of time. Tobosa still dominates the under-story with annual grasses and forbs, both native and non-native. Fires can still burn through this community, but mesquite is well established and will sprout and quickly re-assume dominance.
State 4
Eroded stateCommunity 4.1
Eroded stateVery heavy traffic by livestock and or machinery has caused persistent compaction. Diversion of overland flow and runoff water in farming areas may also have caused rilling and / or gullies to form. The soil profile no longer gets wet so the inherent, vertic, soil properties cannot act to maintain good soil tilth and good rainfall infiltration. This state usually occurs in cultivated regions where small areas of rangeland are used as feeding areas for livestock and roads and bar-ditches have interrupted normal hydrologic patterns.
Transition T1A
State 1 to 2Continuous heavy grazing (managing for annuals) or cultivation and abandonment
Transition T1B
State 1 to 3Proximity to seed source, introduction of seed, lack of fire for long periods of time
Restoration pathway R1A
State 2 to 1Brush management, prescribed grazing
Transition T2A
State 2 to 4Continuous heavy grazing, interuption of overland flow, diversion of run-off, mechanical soil compaction (livestock or equipment)
Restoration pathway R3A
State 3 to 1Brush management, prescribed grazing
Transition T3A
State 3 to 4Continuous heavy grazing coupled with drought or fire
Restoration pathway R4A
State 4 to 2mechanical control of rills and gullies, prescribed grazing
Restoration pathway R3B
State 4 to 3brush management, mechanical land treatment, mechanical gully control, range seeding, prescribed grazing
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant mid grasses 450–800 tobosagrass PLMU3 Pleuraphis mutica 450–650 – sideoats grama BOCU Bouteloua curtipendula 0–80 – vine mesquite PAOB Panicum obtusum 20–75 – 2 Miscellaneous perennial grasses 20–70 curly-mesquite HIBE Hilaria belangeri 0–50 – squirreltail ELEL5 Elymus elymoides 0–35 – cane bluestem BOBA3 Bothriochloa barbinodis 0–30 – blue grama BOGR2 Bouteloua gracilis 0–30 – green sprangletop LEDU Leptochloa dubia 0–20 – common wolfstail LYPH Lycurus phleoides 0–10 – creeping muhly MURE Muhlenbergia repens 0–10 – Hall's panicgrass PAHA Panicum hallii 0–10 – burrograss SCBR2 Scleropogon brevifolius 0–10 – plains bristlegrass SEVU2 Setaria vulpiseta 0–10 – Rothrock's grama BORO2 Bouteloua rothrockii 0–10 – Arizona cottontop DICA8 Digitaria californica 0–10 – black grama BOER4 Bouteloua eriopoda 0–10 – plains lovegrass ERIN Eragrostis intermedia 0–10 – 3 Perennial threeawns 0–50 Fendler threeawn ARPUL Aristida purpurea var. longiseta 0–20 – spidergrass ARTE3 Aristida ternipes 0–20 – spidergrass ARTEG Aristida ternipes var. gentilis 0–20 – poverty threeawn ARDI5 Aristida divaricata 0–10 – Havard's threeawn ARHA3 Aristida havardii 0–10 – Wooton's threeawn ARPA9 Aristida pansa 0–10 – 4 Annual grasses 10–150 little barley HOPU Hordeum pusillum 1–100 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 1–50 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 1–50 – Arizona signalgrass URAR Urochloa arizonica 1–50 – sixweeks fescue VUOC Vulpia octoflora 1–50 – sixweeks threeawn ARAD Aristida adscensionis 0–50 – prairie threeawn AROL Aristida oligantha 0–50 – needle grama BOAR Bouteloua aristidoides 1–50 – sixweeks grama BOBA2 Bouteloua barbata 0–50 – Mexican panicgrass PAHI5 Panicum hirticaule 1–25 – sticky sprangletop LEVI5 Leptochloa viscida 0–25 – feather fingergrass CHVI4 Chloris virgata 0–25 – Arizona brome BRAR4 Bromus arizonicus 0–20 – tapertip cupgrass ERACA Eriochloa acuminata var. acuminata 0–15 – Mexican lovegrass ERME Eragrostis mexicana 0–15 – witchgrass PACA6 Panicum capillare 0–15 – tufted lovegrass ERPE Eragrostis pectinacea 0–10 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 0–10 – delicate muhly MUFR Muhlenbergia fragilis 0–5 – littleseed muhly MUMI Muhlenbergia microsperma 0–5 – Bigelow's bluegrass POBI Poa bigelovii 0–5 – Forb5 Perennial forbs 20–70 Lewis flax LILE3 Linum lewisii 0–25 – Indian rushpea HOGL2 Hoffmannseggia glauca 5–20 – desert globemallow SPAM2 Sphaeralcea ambigua 5–20 – bluedicks DICA14 Dichelostemma capitatum 1–15 – spreading fleabane ERDI4 Erigeron divergens 0–15 – Arizona snakecotton FRAR2 Froelichia arizonica 0–10 – coyote gourd CUPA Cucurbita palmata 0–10 – pearly globe amaranth GONI Gomphrena nitida 0–10 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 1–10 – milkvetch ASTRA Astragalus 0–10 – fingerleaf gourd CUDI Cucurbita digitata 0–10 – Louisiana vetch VILUL2 Vicia ludoviciana ssp. ludoviciana 0–10 – evening primrose OENOT Oenothera 0–10 – Wright's cudweed PSCAC2 Pseudognaphalium canescens ssp. canescens 0–5 – Wright's deervetch LOWR Lotus wrightii 0–5 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 0–5 – American vetch VIAM Vicia americana 0–5 – New Mexico fanpetals SINE Sida neomexicana 0–5 – Missouri gourd CUFO Cucurbita foetidissima 0–5 – dwarf desertpeony ACNA2 Acourtia nana 0–5 – brownfoot ACWR5 Acourtia wrightii 0–5 – largeflower onion ALMA4 Allium macropetalum 0–5 – scarlet spiderling BOCO Boerhavia coccinea 0–5 – whitemouth dayflower COER Commelina erecta 0–5 – southwestern mock vervain GLGO Glandularia gooddingii 0–5 – small matweed GUDE Guilleminea densa 0–2 – desert mariposa lily CAKE Calochortus kennedyi 0–2 – sego lily CANU3 Calochortus nuttallii 0–2 – silverleaf nightshade SOEL Solanum elaeagnifolium 0–2 – variableleaf bushbean MAGI2 Macroptilium gibbosifolium 0–2 – twinleaf senna SEBA3 Senna bauhinioides 0–2 – shrubby purslane POSU3 Portulaca suffrutescens 0–2 – ragged nettlespurge JAMA Jatropha macrorhiza 0–1 – 6 Annual Forbs 20–150 longleaf false goldeneye HELOA2 Heliomeris longifolia var. annua 0–50 – carelessweed AMPA Amaranthus palmeri 0–30 – camphorweed HESU3 Heterotheca subaxillaris 0–25 – tanseyleaf tansyaster MATA2 Machaeranthera tanacetifolia 0–25 – sensitive partridge pea CHNI2 Chamaecrista nictitans 1–25 – Arizona popcornflower PLAR Plagiobothrys arizonicus 0–25 – western tansymustard DEPI Descurainia pinnata 0–20 – common sunflower HEAN3 Helianthus annuus 0–20 – Arizona poppy KAGR Kallstroemia grandiflora 0–20 – intermediate pepperweed LEVIM Lepidium virginicum var. medium 0–20 – crestrib morning-glory IPCO2 Ipomoea costellata 0–15 – woolly plantain PLPA2 Plantago patagonica 0–15 – spreading fanpetals SIAB Sida abutifolia 0–15 – slender goldenweed MAGR10 Machaeranthera gracilis 0–10 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–10 – coastal bird's-foot trefoil LOSAB Lotus salsuginosus var. brevivexillus 0–10 – goosefoot CHENO Chenopodium 0–10 – miniature woollystar ERDI2 Eriastrum diffusum 0–10 – Coulter's spiderling BOCO2 Boerhavia coulteri 0–10 – New Mexico thistle CINE Cirsium neomexicanum 0–10 – scrambled eggs COAU2 Corydalis aurea 0–10 – cryptantha CRYPT Cryptantha 0–5 – fringed redmaids CACI2 Calandrinia ciliata 0–5 – sorrel buckwheat ERPO4 Eriogonum polycladon 0–5 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–5 – spurge EUPHO Euphorbia 0–5 – blanketflower GAILL Gaillardia 0–5 – star gilia GIST Gilia stellata 0–5 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–5 – hollowleaf annual lupine LUSU3 Lupinus succulentus 0–5 – Nuttall's povertyweed MONU Monolepis nuttalliana 0–5 – green carpetweed MOVE Mollugo verticillata 0–5 – foothill deervetch LOHU2 Lotus humistratus 0–5 – Goodding's bladderpod LEGO2 Lesquerella gooddingii 0–5 – wheelscale saltbush ATEL Atriplex elegans 0–5 – sleepy silene SIAN2 Silene antirrhina 0–5 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–5 – purslane PORTU Portulaca 0–5 – desert Indianwheat PLOV Plantago ovata 0–5 – sawtooth sage SASU7 Salvia subincisa 0–5 – Texas stork's bill ERTE13 Erodium texanum 0–3 – wedgeleaf draba DRCU Draba cuneifolia 0–2 – American wild carrot DAPU3 Daucus pusillus 0–2 – sacred thorn-apple DAWR2 Datura wrightii 0–2 – Lemmon's linanthus LELE29 Leptosiphon lemmonii 0–2 – manybristle chinchweed PEPA2 Pectis papposa 0–2 – phlox PHLOX Phlox 0–2 – Arizona lupine LUAR4 Lupinus arizonicus 0–2 – New Mexico copperleaf ACNE Acalypha neomexicana 0–2 – ragwort SENEC Senecio 0–2 – desert unicorn-plant PRAL4 Proboscidea althaeifolia 0–2 – doubleclaw PRPA2 Proboscidea parviflora 0–2 – Shrub/Vine7 Half shrubs 0–50 bastardsage ERWR Eriogonum wrightii 1–25 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–10 – burroweed ISTE2 Isocoma tenuisecta 0–5 – yerba de pasmo BAPT Baccharis pteronioides 0–5 – threadleaf snakeweed GUMI Gutierrezia microcephala 0–2 – 8 Miscellaneous shrubs 0–25 catclaw acacia ACGR Acacia greggii 0–5 – pale desert-thorn LYPA Lycium pallidum 0–5 – catclaw mimosa MIACB Mimosa aculeaticarpa var. biuncifera 0–5 – western honey mesquite PRGLT Prosopis glandulosa var. torreyana 0–2 – velvet mesquite PRVE Prosopis velutina 0–2 – lotebush ZIOB Ziziphus obtusifolia 0–2 – fourwing saltbush ATCA2 Atriplex canescens 0–2 – fairyduster CAER Calliandra eriophylla 0–2 – knifeleaf condalia COSP3 Condalia spathulata 0–2 – Warnock's snakewood COWA Condalia warnockii 0–2 – trailing krameria KRLA Krameria lanceolata 0–2 – winterfat KRLA2 Krascheninnikovia lanata 0–2 – whitethorn acacia ACCO2 Acacia constricta 0–2 – 9 Succulents 0–25 walkingstick cactus CYSP8 Cylindropuntia spinosior 0–10 – cactus apple OPEN3 Opuntia engelmannii 0–10 – tulip pricklypear OPPH Opuntia phaeacantha 0–5 – banana yucca YUBA Yucca baccata 0–5 – Christmas cactus CYLE8 Cylindropuntia leptocaulis 0–5 – dollarjoint pricklypear OPCH Opuntia chlorotica 0–5 – sacahuista NOMI Nolina microcarpa 0–2 – soaptree yucca YUEL Yucca elata 0–2 – Palmer's century plant AGPA3 Agave palmeri 0–2 – rainbow cactus ECPEP Echinocereus pectinatus var. pectinatus 0–1 – spinystar ESVI2 Escobaria vivipara 0–1 – candy barrelcactus FEWI Ferocactus wislizeni 0–1 – Table 9. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
The plant community on this site is suitable for grazing at any season by all classes of cattle. Clay soils make for a long summer green season. Dark colored soils, high in organic matter and exchangeable bases make for fairly good quality, green tobosa herbage. Fencing and grazing systems will be needed to effectively utilize this site and take adequate care of adjacent and/or included sites that produce more palatable forage. Herbaceous forage will be deficient in protein in the winter. Dormant tobosa is very unpalatable.
Water developments are very important to wildlife species on this site. Being open grassland, this site is home to a variety of small herbivores, birds, and their associated predators. With the exception of antelope, larger wildlife species use this site mainly as a foraging area.Hydrological functions
Due to severe soil cracking and churning (producing rough and porous surfaces), this site has very high infiltration rates when soils are dry. It produces runoff only when soils are moist. Vertic soil properties eliminate soil compaction by livestock traffic each year, as long as stocking rates are moderate and heavy stocking is not persistent during times of the year when soils are moist.
Recreational uses
Hunting, hiking, horseback riding, photography and bird-watching.
Wood products
Mesquite is shrubby if on this site due to clayey soils. Mesquite fuelwood, if present, is barely sufficient for campfires and branding fires.
Other products
Clay
Supporting information
Inventory data references
Range 417s include 4 in good condition and 1 in fair condition.
Type locality
Location 1: Cochise County, AZ Township/Range/Section T23S R30E S1 General legal description Peterson Ranch Location 2: Graham County, AZ Township/Range/Section T11S R22E S9 General legal description Sierra Bonita Ranch Location 3: Greenlee County, AZ Township/Range/Section T10S R31E S14 General legal description Lazy B Ranch Contributors
Dan Robinett
Larry D. Ellicott
Steve Barker
UnknownApproval
Scott Woodall, 7/21/2020
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) Dave Womack, Dan Robinett Contact for lead author NRCS Tucson Area Office Date 02/24/2005 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
None present on this site. -
Presence of water flow patterns:
Uncommon; probably cover no more than 2-5% of area; discontinuous, 2-20 feet in length in low gravel cover areas, broken by plants and micro topography from cracking and swelling; High gravel cover areas (50% cover) at this site results in sheet flow of these areas; Gravel cover averaged 9% across site. -
Number and height of erosional pedestals or terracettes:
Accumulated pedastals are 1 inch tall and are common on perennial grass plants; terracettes are very uncommon due to low slope. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Estimated from 200 points at 60%. -
Number of gullies and erosion associated with gullies:
None present on this site. -
Extent of wind scoured, blowouts and/or depositional areas:
None present on this site. -
Amount of litter movement (describe size and distance expected to travel):
All litter size classes staying in place. -
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 values of 1-2 in bare ground areas and 4-6 in canopy areas. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Thin (1/8 inch) rain drop compacted laminar layer, weak granular; Color is 10YR5/4 Dry, 10YR3/3 Moist; No A horizon, Clayloam texture to 6 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Cover estimated from 200 points was: Canopy 14%, Basal 7% Litter 7% and Gravel 9%; 85% of canopy cover is perennial grasses and 14% is subshrubs and 1% shrubs & succulents. Cover is relatively well dispersed thoughout site, with bare patches 10-20 feet wide 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 present on this site. Penetrometer tests with weight dropped 5 times at a distance from top of weight to topo of impact ring = 2.24 feet were: average = 3.26 inches, s.d = 0.46 inches. -
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 grassSub-dominant:
subshrubsOther:
annual forbsAdditional:
Perennial grass >> subshrubs > annual forbs > shrubs > perennial forbs > succulents -
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
20% basal mortality (prior years mortality not well evidenced). -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
600 lbs/acre unfavorable precipitation, 1,000 lbs/acre normal precipitation, 1,500 lbs/acre 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:
None present on this site. Shrubs not likely to tolerate shrink/swell soil properties. -
Perennial plant reproductive capability:
Not affected even following several years of prolonged drought period for region.
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