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Ecological site R041XB215AZ
Sandy Loam Upland
8-12" p.z.
Last updated: 4/12/2021
Accessed: 08/30/2026
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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
Major Land Resource Area (MLRA) 41 represents the most northern extent of the Sierra Madre Occidental, or in English, the “mother mountains of the west.” The Sierra Madre Occidental is a massive, rugged mountain system that runs northwest from the Rio Grande de Santiago, in the state of Jalisco, Mexico, through the states of Sonora and Chihuahua, and ending in Arizona and New Mexico. Through Mexico, this mountain system runs parallel to the Pacific coast and, as it crosses into the United States and confronts the tectonic folding and rifting of the Basin and Range Physiographic Province, the land mass geographically breaks into smaller, isolated mountain ranges, called “sky islands.” The centralizing theme for this MLRA can be summed up as a series of inland islands extending from their mainland, the Sierra Madre Occidental, surrounded by a sea of desert grassland. To the west, the Madrean Archipelago bounds the Sonoran Basin and Range where several sky islands in southern Arizona grade into Sonoran Desert basins; to the north it bounds the contiguous mountains and geology of the Mogollon Transition area; and to the east, in New Mexico, it bounds the geology of the Rio Grande Rift. MLRA 41 is primarily a rangeland subdivision with small amounts of irrigated cropland. It encompasses approximately 13M acres.
LRU notes
Land Resource Unit 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.
Classification relationships
USDA-NRCS Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin: Western Range and Irrigated Region D; Major Land Resource Area 41, Southeastern Arizona Basin and Range; Land Resource Unit 41-3, Semi-Desert Grassland; Ecological Site Sandy Loam Upland, 8"-12" p.z.
U.S. Environmental Protection Agency, Ecological Regions of North America: Level I, Region 12, Southern Semi-Arid Highlands; Level II, 12.1 Western Sierra Madre Piedmont, Level III, Ecoregion 79 Madrean Archipelago, 79a, Apachian Valleys and Low Hills.
USDA-USFS Ecological Subregions: Sections of the Conterminous United States: Section 321 Basin and Range; Section 321A, Basin and Range Section.Ecological site concept
Sandy Loam Upland, 8”-12” p.z., ecological site is found on gently sloping uplands with deep soils. An argillic horizon is below 4”-16” of sandy loam textured soils. While surface soils are non-calcareous (upper 10 inches), calcic horizons may be found below the argillic horizon.
Associated sites
R041XB210AZ Loamy Upland 8-12" p.z.
R041XB205AZ Shallow Hills 8-12" p.z.
Similar sites
R040XA118AZ Sandy Loam Upland 10"-13" p.z.
R041XC319AZ Sandy Loam Upland 12-16" p.z.
Table 1. Dominant plant species
Tree (1) Prosopis glandulosa var. torreyana
Shrub (1) yucca elata
(2) ephedra fasciculataHerbaceous (1) muhlenbergia porteri
(2) bouteloua eriopodaPhysiographic features
This site occurs in the lowest elevations of the Madrean Basin and Range province in southeastern Arizona. It occurs on fan terraces and gently sloping uplands.
Table 2. Representative physiographic features
Landforms (1) Valley
(2) Fan piedmont
Flooding frequency None Ponding frequency None Elevation 2600 – 4000 ft Slope 1 – 15 % Aspect Aspect is not a significant factor Climatic features
Precipitation ranges from 8-12 inches annually. More than half falls during Jul-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 (characteristic range) 160-190 days Freeze-free period (characteristic range) 190-230 days Precipitation total (characteristic range) 10-10 in Frost-free period (actual range) 150-190 days Freeze-free period (actual range) 170-230 days Precipitation total (actual range) 10-10 in Frost-free period (average) 170 days Freeze-free period (average) 200 days Precipitation total (average) 10 in Characteristic rangeActual rangeBarLineFigure 2. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 3. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 4. Monthly maximum temperature range
BarLineFigure 5. Monthly average minimum and maximum temperature
Figure 6. Annual precipitation pattern
Figure 7 Annual average temperature pattern
Climate stations used
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(1) FT THOMAS 2 SW [USC00023150], Pima, AZ
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(2) SAFFORD AGRICULTRL CTR [USC00027390], Safford, AZ
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(3) SAN SIMON [USC00027560], San Simon, AZ
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(4) BOWIE [USC00020958], San Simon, AZ
">Influencing water features
There are no water features associated with this site.
Soil features
These soils are deep and loamy textured. They have thick (4-16 inch) surface horizons that are sandyloam in texture, over an argillic horizon. Surface soils (10 inches) are non-calcareous, but some soils have calcic horizons below the argillic horizon. Although several soil series are correlated in map unit components to this ecological site, Bucklebar soil series is most representative of Sandy Loam Upland, 8-12” p.z..
Table 4. Representative soil features
Surface texture (1) Sandy loam
(2) Very gravelly sandy loam
(3) Gravelly sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate to moderately slow Soil depth 60 in Surface fragment cover <=3" 5 – 40 % Surface fragment cover >3" 0 – 5 % Available water capacity
(0-40in)6.5 – 8.2 in Calcium carbonate equivalent
(0-40in)0 – 25 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 2 Soil reaction (1:1 water)
(0-40in)7 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)5 – 55 % Subsurface fragment volume >3"
(Depth not specified)0 – 5 % Ecological dynamics
Sandy Loam Upland, 8"-12" pz, ecological site is a mixed shrubland with a perennial grass understory. Plant community variation occurs both along the precipitation gradient (from low end of the precipitation zone to the high) and with depth to argillic horizon. Perennial grass composition, basal cover, and distribution are affected. At the lower end of the precipitation gradient (and with thin surface horizon over argillic), bare areas increase in diameter and connectivity, tobosa grass dominates perennial grasses; while at the high end of the precipitation gradient (and with increased depth to argillic), bush muhly and black grama dominate and bare areas are less commonly connected. Several species of perennial grasses, sand dropseed and three-awns for example, come in and out of the plant community as weather patterns fluctuate between wet and dry cycles. Drought is the primary natural disturbance on this ecological site. As human-driven disturbances disrupt this site, 3 alternative states arise: State 2, Non-native Grass; State 3, Large Shrub-Annuals, and State 4, Large Shrub-Eroded.
State and transition model
Custom diagramStandard diagram
Figure 8. State and Transition Model, Sandy Loam Upland, 8"-12" p.z.
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 textEcosystem states
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
Native Grass-ShrubNative Grass-Shrub State has two Community Phases that fluctuate with dry/wet weather cycling. The Reference Plant Community (CP1.1) is a an open community of perennial grasses and desert shrubs and cacti. Annual forbs and grasses, of both the winter and summer wet seasons, are very important in the plant community in their respective (wet) seasons. Tobosa, black grama and bush muhly are the dominant perennial grasses, with lesser amounts of perennial mid-grasses such as threeawns and dropseeds. The cover of some shallow rooted grass species, like curly mesquite and Rothrock grama fluctuate widely from wet to dry years. Climate fluctuations, cycling of wet winters, favors shrub growth thus allowing the shrub dominance in CP1.1; extended drought will contract both perennial grass and shrub canopy covers, transitioning the community phase to CP1.2. Natural fire may occasionally occur in this LRU but is not thought to have recurred with a frequency to shape this plant community.
Community 1.1
Historic Climax Plant CommunityThe native potential plant community on this site is a mixture of perennial grasses and desert shrubs and cacti. Annual forbs and grasses, of both the winter and summer seasons, are very important in the plant community in their respective (wet) seasons. Black grama and bush muhly are the dominant perennial grasses, with lesser amounts of threeawns. The cover of shallow rooted grass species, like Rothrock grama fluctuate widely from wet to dry years. Lehmann lovegrass can invade and persist in this plant community, but will fluctuate (in amounts) with climate and not become dominant.
Figure 9. 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 150 275 655 Forb 7 40 170 Shrub/Vine 45 100 140 Tree 15 35 100 Total 217 450 1065 Table 6. Soil surface cover
Tree basal cover 0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 0-0% Forb basal cover 0-0% Non-vascular plants 0% Biological crusts 0-10% Litter 20-70% Surface fragments >0.25" and <=3" 10-40% Surface fragments >3" 0-10% Bedrock 0% Water 0% Bare ground 10-80% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 1-5% 1-15% 1-15% >0.5 <= 1 – 5-10% 5-20% 1-10% >1 <= 2 – 1-5% 5-10% 0-5% >2 <= 4.5 – 1-5% 0-2% 0-1% >4.5 <= 13 1-5% 0-2% – – >13 <= 40 0-2% – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Community 1.2
Shrub-Suffrutescent GrassState 2
Non-Native GrassNon-Native Grass State, is a cyclic large shrub-annual forbs / large shrub-Lehmann lovegrass plant community. Community Phase 2.1 persists for about 10 years following brush management combined with range seeding. The restoration from State 3, prescribed grazing without brush management, will result in CP 2.2 with Lehmann lovegrass in the soil seedbank. The prevalence of Lehamnn lovegrass within the soil seedbank no longer requires range seeding. Once a soil seedbank is established, LL will persist in the plant community while its basal cover varies widely with climate, elevation, depth of surface soil over argillic. Lehmann lovegrass only dominates the entire plant community in CP 2.1, after brush management and seeding, but it will dominate the herbaceous layer of the plant community once established. Lehmann lovegrass production does not exceed 400# / ac during Non-Native lovegrass cycles.
Community 2.1
Non-Native GrassThis state occurs where Lehmann, and in some cases Boers, lovegrass has been seeded; usually in combination with mechanical mesquite control. The cover of Lehmann lovegrass varies widely with climate, ranging from 1-5% canopy in dry years up to 20-40% canopy in years with wet summers. Lehmann never dominates the plant community on this site but does dominate the herbaceous layer of the plant community once established.
Community 2.2
Shrubs-Annuals
Figure 10. Sandyloam Upland 8-12" pz.
This state occurs where mesquite has increased from 2 to 10% canopy and, with other shrubs, dominates the plant community. Native perennial grasses (suffrutescent) and forbs are absent from the plant community. Native and non-native annuals are very important in the plant community in their respective (wet) seasons.
Community 2.3
Srubs-Non-Native GrassState 3
Large Shrub-AnnualsLarge Shrubs-Annuals, comes about after years of heavy grazing. Suffrutescent grasses are confined to tightly protected areas within shrub and cactus canopies leaving large bare areas as inter-shrub spaces.
Community 3.1
Mesquite, Lehmann lovegrassThis state occurs where Lehmann, and in some cases, Boer lovegrass has been seeded. This usually occurs in combination with mechanical control of mesquite. Lehmann lovegrass ranges from about 5% cover in dry years to 40% cover in wet summers. It never dominates the plant community but will dominate the herbaceous layer.
State 4
Large Shrub, ErodedLarge Shrubs, Eroded, has active, accelerated erosion. This state occurs where mesquite canopy is heavy (15-25%) and the interaction of drought and continuous grazing has resulted in severe sheet, rill and, in some cases, gully erosion on the site.
These areas are usually near historic watering locations and are characterized by soil compaction due to trailing and heavy livestock traffic.Community 4.1
Mesquite, annualsThis state occurs where mesquite and other shrubs dominate the plant community and native and non-native annuals dominate the herbaceous layer of the plant community. Native perennial grasses and forbs have been removed from the plant community. Repeated fires can develop this plant community.
State 5
Mesquite, erosionCommunity 5.1
Mesquite, erosionThis state occurs where mesquite canopy ranges from 15-25% and severe sheet, rill and, in some cases, gully erosion has occurred. This state usually occurs near historic water locations and is characterized by soil compaction due to trailing and heavy livestock traffic.
Transition T1A
State 1 to 3yearlong, heavy livestock grazing without native grass management
Transition T2A
State 2 to 4yearlong, heavy livestock grazing
Restoration pathway R3B
State 3 to 1None known
Restoration pathway R3A
State 3 to 2prescribed grazing, non-native seed introduction, brush management
Transition T3A
State 3 to 4yearlong, heavy livestock grazing without native grass management
Restoration pathway R4A
State 4 to 2brush management, mechanical land treatment, 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 Perennial Grasses 100–300 bush muhly MUPO2 Muhlenbergia porteri 25–125 – black grama BOER4 Bouteloua eriopoda 25–100 – Arizona cottontop DICA8 Digitaria californica 1–50 – plains bristlegrass SEVU2 Setaria vulpiseta 1–25 – 2 Miscellaneous Perennial Grasses 15–75 whiplash pappusgrass PAVA2 Pappophorum vaginatum 0–25 – sideoats grama BOCU Bouteloua curtipendula 1–20 – spike dropseed SPCO4 Sporobolus contractus 1–15 – sand dropseed SPCR Sporobolus cryptandrus 1–15 – cane bluestem BOBA3 Bothriochloa barbinodis 1–15 – mesa dropseed SPFL2 Sporobolus flexuosus 0–10 – blue grama BOGR2 Bouteloua gracilis 0–10 – low woollygrass DAPU7 Dasyochloa pulchella 1–10 – tanglehead HECO10 Heteropogon contortus 0–10 – sand muhly MUAR2 Muhlenbergia arenicola 0–10 – curly-mesquite HIBE Hilaria belangeri 0–5 – green sprangletop LEDU Leptochloa dubia 0–5 – tobosagrass PLMU3 Pleuraphis mutica 0–5 – burrograss SCBR2 Scleropogon brevifolius 0–5 – Hall's panicgrass PAHA Panicum hallii 0–5 – vine mesquite PAOB Panicum obtusum 0–5 – false Rhodes grass TRCR9 Trichloris crinita 0–5 – Arizona muhly MUAR3 Muhlenbergia arizonica 0–2 – squirreltail ELEL5 Elymus elymoides 0–2 – big sacaton SPWR2 Sporobolus wrightii 0–1 – 3 Perennial threeawns 20–130 Santa Rita threeawn ARCAG Aristida californica var. glabrata 5–50 – spidergrass ARTE3 Aristida ternipes 5–50 – spidergrass ARTEG Aristida ternipes var. gentilis 1–25 – Parish's threeawn ARPUP5 Aristida purpurea var. parishii 0–25 – purple threeawn ARPU9 Aristida purpurea 1–25 – Fendler threeawn ARPUL Aristida purpurea var. longiseta 0–5 – blue threeawn ARPUN Aristida purpurea var. nealleyi 0–5 – poverty threeawn ARDI5 Aristida divaricata 0–5 – 4 Annual grasses 15–150 prairie threeawn AROL Aristida oligantha 1–50 – needle grama BOAR Bouteloua aristidoides 5–50 – Rothrock's grama BORO2 Bouteloua rothrockii 5–50 – sixweeks fescue VUOC Vulpia octoflora 1–25 – sixweeks grama BOBA2 Bouteloua barbata 0–20 – Mexican panicgrass PAHI5 Panicum hirticaule 1–20 – Arizona signalgrass URAR Urochloa arizonica 1–20 – sixweeks threeawn ARAD Aristida adscensionis 1–15 – feather fingergrass CHVI4 Chloris virgata 0–15 – witchgrass PACA6 Panicum capillare 0–10 – Bigelow's bluegrass POBI Poa bigelovii 0–5 – Arizona brome BRAR4 Bromus arizonicus 0–5 – tapertip cupgrass ERACA Eriochloa acuminata var. acuminata 0–5 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 0–5 – tufted lovegrass ERPEP2 Eragrostis pectinacea var. pectinacea 0–5 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 0–5 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 0–5 – delicate muhly MUFR Muhlenbergia fragilis 0–2 – littleseed muhly MUMI Muhlenbergia microsperma 0–2 – Forb5 Perennial forbs 2–20 dwarf desertpeony ACNA2 Acourtia nana 1–5 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 1–5 – desert marigold BAMU Baileya multiradiata 1–5 – slender poreleaf POGR5 Porophyllum gracile 0–5 – desert globemallow SPAM2 Sphaeralcea ambigua 1–5 – bluedicks DICA14 Dichelostemma capitatum 0–2 – slender janusia JAGR Janusia gracilis 0–2 – ragged nettlespurge JAMA Jatropha macrorhiza 0–1 – Parry's false prairie-clover MAPA7 Marina parryi 0–1 – lacy tansyaster MAPIP4 Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida 0–1 – plains blackfoot MELE2 Melampodium leucanthum 0–1 – wishbone-bush MILAV Mirabilis laevis var. villosa 0–1 – desert tobacco NIOB Nicotiana obtusifolia 0–1 – spreading fleabane ERDI4 Erigeron divergens 0–1 – desert trumpet ERIN4 Eriogonum inflatum 0–1 – southwestern mock vervain GLGO Glandularia gooddingii 0–1 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 0–1 – pricklyleaf dogweed THAC Thymophylla acerosa 0–1 – Rocky Mountain zinnia ZIGR Zinnia grandiflora 0–1 – canaigre dock RUHY Rumex hymenosepalus 0–1 – twinleaf senna SEBA3 Senna bauhinioides 0–1 – Coues' cassia SECO10 Senna covesii 0–1 – silverleaf nightshade SOEL Solanum elaeagnifolium 0–1 – scarlet spiderling BOCO Boerhavia coccinea 0–1 – desert mariposa lily CAKE Calochortus kennedyi 0–1 – sego lily CANU3 Calochortus nuttallii 0–1 – whitemargin sandmat CHAL11 Chamaesyce albomarginata 0–1 – leatherweed CRPO5 Croton pottsii 0–1 – fingerleaf gourd CUDI Cucurbita digitata 0–1 – coyote gourd CUPA Cucurbita palmata 0–1 – tuber anemone ANTU Anemone tuberosa 0–1 – narrowleaf silverbush ARLA12 Argythamnia lanceolata 0–1 – New Mexico silverbush ARNE2 Argythamnia neomexicana 0–1 – perennial rockcress ARPE2 Arabis perennans 0–1 – dense ayenia AYMI Ayenia microphylla 0–1 – hairyseed bahia BAAB Bahia absinthifolia 0–1 – brownfoot ACWR5 Acourtia wrightii 0–1 – poreleaf dogweed ADPO2 Adenophyllum porophyllum 0–1 – trailing windmills ALIN Allionia incarnata 0–1 – largeflower onion ALMA4 Allium macropetalum 0–1 – 6 Annual forbs 5–150 Coulter's spiderling BOCO2 Boerhavia coulteri 0–25 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–25 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–25 – Arizona popcornflower PLAR Plagiobothrys arizonicus 0–20 – desert Indianwheat PLOV Plantago ovata 0–20 – western tansymustard DEPI Descurainia pinnata 0–20 – Arizona poppy KAGR Kallstroemia grandiflora 0–20 – combseed PECTO Pectocarya 0–20 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–15 – intermediate pepperweed LEVIM Lepidium virginicum var. medium 0–15 – tanseyleaf tansyaster MATA2 Machaeranthera tanacetifolia 0–15 – wheelscale saltbush ATEL Atriplex elegans 0–15 – bristly fiddleneck AMTE3 Amsinckia tessellata 0–15 – carelessweed AMPA Amaranthus palmeri 0–10 – Esteve's pincushion CHST Chaenactis stevioides 0–10 – whitestem blazingstar MEAL6 Mentzelia albicaulis 0–10 – miniature woollystar ERDI2 Eriastrum diffusum 0–10 – sorrel buckwheat ERPO4 Eriogonum polycladon 0–10 – manybristle chinchweed PEPA2 Pectis papposa 0–10 – New Mexico plumeseed RANE Rafinesquia neomexicana 0–5 – thelypody THELY Thelypodium 0–5 – Texas stork's bill ERTE13 Erodium texanum 0–5 – wedgeleaf draba DRCU Draba cuneifolia 0–5 – flatcrown buckwheat ERDE6 Eriogonum deflexum 0–5 – redstar IPCO3 Ipomoea coccinea 0–5 – ivyleaf morning-glory IPHE Ipomoea hederacea 0–5 – Nuttall's povertyweed MONU Monolepis nuttalliana 0–5 – foothill deervetch LOHU2 Lotus humistratus 0–5 – coastal bird's-foot trefoil LOSAB Lotus salsuginosus var. brevivexillus 0–5 – slender goldenweed MAGR10 Machaeranthera gracilis 0–5 – cryptantha CRYPT Cryptantha 0–5 – milkvetch ASTRA Astragalus 0–5 – Gordon's bladderpod LEGO Lesquerella gordonii 0–5 – hairy prairie clover DAMO Dalea mollis 0–2 – American wild carrot DAPU3 Daucus pusillus 0–2 – fringed redmaids CACI2 Calandrinia ciliata 0–2 – white tackstem CAWR Calycoseris wrightii 0–2 – brittle spineflower CHBR Chorizanthe brevicornu 0–2 – hyssopleaf sandmat CHHY3 Chamaesyce hyssopifolia 0–2 – desert evening primrose OEPR Oenothera primiveris 0–2 – Florida pellitory PAFL3 Parietaria floridana 0–2 – Arizona lupine LUAR4 Lupinus arizonicus 0–2 – green carpetweed MOVE Mollugo verticillata 0–2 – warty caltrop KAPA Kallstroemia parviflora 0–2 – hairy desertsunflower GECA2 Geraea canescens 0–2 – star gilia GIST Gilia stellata 0–2 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–2 – woollyhead neststraw STMI2 Stylocline micropoides 0–2 – phacelia PHACE Phacelia 0–2 – sleepy silene SIAN2 Silene antirrhina 0–2 – Coulter's globemallow SPCO2 Sphaeralcea coulteri 0–1 – chia SACO6 Salvia columbariae 0–1 – sawtooth sage SASU7 Salvia subincisa 0–1 – spreading fanpetals SIAB Sida abutifolia 0–1 – sand fringepod THCU Thysanocarpus curvipes 0–1 – southwestern mock vervain GLGO Glandularia gooddingii 0–1 – crestrib morning-glory IPCO2 Ipomoea costellata 0–1 – 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 – desert unicorn-plant PRAL4 Proboscidea althaeifolia 0–1 – doubleclaw PRPA2 Proboscidea parviflora 0–1 – exserted Indian paintbrush CAEXE Castilleja exserta ssp. exserta 0–1 – yellow tackstem CAPA7 Calycoseris parryi 0–1 – scrambled eggs COAU2 Corydalis aurea 0–1 – hoary bowlesia BOIN3 Bowlesia incana 0–1 – southwestern pricklypoppy ARPL3 Argemone pleiacantha 0–1 – annual agoseris AGHE2 Agoseris heterophylla 0–1 – Shrub/Vine7 Dominant shrubs 7–50 catclaw acacia ACGR Acacia greggii 5–15 – fourwing saltbush ATCA2 Atriplex canescens 1–15 – whitethorn acacia ACCO2 Acacia constricta 0–10 – creosote bush LATR2 Larrea tridentata 0–10 – littleleaf sumac RHMI3 Rhus microphylla 0–10 – whitethorn acacia ACCOP9 Acacia constricta var. paucispina 0–5 – longleaf jointfir EPTR Ephedra trifurca 0–5 – 8 Miscellaneous shrubs 0–10 Wright's beebrush ALWR Aloysia wrightii 0–1 – crucifixion thorn CAHO3 Canotia holacantha 0–1 – spiny hackberry CEEH Celtis ehrenbergiana 0–1 – American tarwort FLCE Flourensia cernua 0–1 – ocotillo FOSP2 Fouquieria splendens 0–1 – water jacket LYAN Lycium andersonii 0–1 – Berlandier's wolfberry LYBE Lycium berlandieri 0–1 – pale desert-thorn LYPA Lycium pallidum 0–1 – catclaw mimosa MIACB Mimosa aculeaticarpa var. biuncifera 0–1 – Gray's feverfew PACO11 Parthenium confertum 0–1 – lotebush ZIOB Ziziphus obtusifolia 0–1 – 9 Half shrubs 12–50 desert zinnia ZIAC Zinnia acerosa 10–40 – shortleaf baccharis BABR Baccharis brachyphylla 5–15 – fairyduster CAER Calliandra eriophylla 0–10 – bastardsage ERWR Eriogonum wrightii 1–10 – broom snakeweed GUSA2 Gutierrezia sarothrae 1–10 – burroweed ISTE2 Isocoma tenuisecta 1–10 – littleleaf ratany KRER Krameria erecta 0–5 – whitestem paperflower PSCO2 Psilostrophe cooperi 0–5 – winterfat KRLA2 Krascheninnikovia lanata 0–1 – rough menodora MESC Menodora scabra 0–1 – threadleaf snakeweed GUMI Gutierrezia microcephala 0–1 – turpentine bush ERLA12 Ericameria laricifolia 0–1 – rayless goldenhead ACSP Acamptopappus sphaerocephalus 0–1 – 10 Succulents 11–30 walkingstick cactus CYSP8 Cylindropuntia spinosior 5–15 – soaptree yucca YUEL Yucca elata 5–15 – tulip pricklypear OPPH Opuntia phaeacantha 1–5 – candy barrelcactus FEWI Ferocactus wislizeni 0–2 – cactus apple OPEN3 Opuntia engelmannii 0–2 – purple pricklypear OPMA8 Opuntia macrocentra 0–2 – devil's cholla GRKU Grusonia kunzei 0–1 – Graham's nipple cactus MAGR9 Mammillaria grahamii 0–1 – Engelmann's hedgehog cactus ECEN Echinocereus engelmannii 0–1 – pinkflower hedgehog cactus ECFA Echinocereus fasciculatus 0–1 – buck-horn cholla CYAC8 Cylindropuntia acanthocarpa 0–1 – Christmas cactus CYLE8 Cylindropuntia leptocaulis 0–1 – banana yucca YUBA Yucca baccata 0–1 – Tree11 Dominant trees 15–100 western honey mesquite PRGLT Prosopis glandulosa var. torreyana 15–50 – velvet mesquite PRVE Prosopis velutina 1–50 – Table 9. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 12. Community 2.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 13. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 14. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 15. Community 5.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This site produces some perennial forage for livestock. It wet (El Nino) winters it produces a tremendous amount of annual forbs and grasses, all of which are excellent forage. The site is home to a variety of small mammals and birds and their associated predators. It is mainly a foraging area for larger mammals like mule deer and javalina.
Hydrological functions
These soils are coarse to medium textured and poor producers of runoff.
Recreational uses
Hunting, horseback riding, hiking, wildlife observation, photography, rock hounding and bird watching.
Wood products
Limited mesquite wood for campfires and firewood.
Supporting information
Contributors
Dan Robinett
Larry D. EllicottApproval
Curtis Talbot, 4/12/2021
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 Contact for lead author USDA-NRCS Tucson MLRA Soil Survey Office Date 12/12/2012 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
Rills have formed out of water flow paths in recent past. They are 10-30 feet in length and continuous with flow paths. -
Presence of water flow patterns:
Water flow paths occupy 10% of the surface area. Steeper sections have flow paths which are continuous and smaller flow paths are discontinuous and 10-20 feet in length. -
Number and height of erosional pedestals or terracettes:
Pedestals are common on all longer lived grasses and sub-shrubs and are from 1-2 inches in height. Terracettes are uncommon on the site except in water flow paths where they occur at 10-20 foot intervals in smaller flow paths. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare soil is 10-80%, gravel ranges from 5-35% and basal cover of live perennial grasses is 1-2%. Bare areas are 3-5’ in diameter and generally connected. -
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):
Both fine and coarse litter size-classes are moving moderate distances (10-20 feet) in water flow paths, between vegetation patches, and on areas with increased slope. All litter size-classes are staying in place within vegetation patches and flat areas. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Values from a soil slake test ratings were 2-3s from outside canopy and were 4-6s from under canopy. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
A horizon is 7 inches thick with a weak sub-angular blocky structure. Colors are 7.5 YR 5/4 dry and 7.5 YR 3/4 moist. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Perennial grass canopy cover ranges from 3-20%; sub-shrub cover 1-5%; tree cover 5-7%; succulents 1-2%; annuals are highly variable. The patch-distribution of perennial grass cover plays the primary role in slowing sheet flow run-off coming from bare areas and allowing infiltration. As tree cover increases on the site, surface water flow becomes more continuous, therefore, resulting in decreased infiltration. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None present, average depth of penetration from an ARS field penetrometer with a 2.2 kg. sliding hammer is 8.5 cm. The argillic horizon could be mistaken for compacted layer. -
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:
Dom.Per.grasses (black grama, bush muhhly) > Per.3-awns > Misc.Per.Grasses = Ann.Grass >>Sub-dominant:
Dom.Trees > Half Shrubs = Succulents = Dom.Shrubs (4-wing saltbush, catclaw) = Forbs >> Misc.Shrubs.Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Plant mortality strongly affected by weather patterns; >20% mortality on perennial grasses and sub-shrubs can occur during short-term drought. Mortality on trees (<10%) is steady. -
Average percent litter cover (%) and depth ( in):
From the ESD, litter cover can be from 15-65% on this site. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
217 lbs/ac. in a below average year; 550 lbs/ac. in an average year; 1065 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:
Mesquite (mesquite canopy should be less than 5% on this site). Other invasive species present include both Lehmann and Boer lovegrass. -
Perennial plant reproductive capability:
Moderately impaired by drought on perennial grass and sub-shrub species.
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