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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
R041XC304AZ Clayey Upland 12-16" p.z.
R041XC305AZ Clay Loam Upland 12-16" p.z.
R041XC312AZ Loamy Bottom 12-16" p.z.
Similar sites
R041XB202AZ Clayey Swale 8-12" p.z.
R040XA102AZ Clayey Swale 10"-13" 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 alluvial fans and floodplains. The site receives extra moisture in the form of runoff from adjacent upland areas.
Table 2. Representative physiographic features
Landforms (1) Alluvial fan
(2) Flood plain
(3) Swale
Flooding duration Extremely brief (0.1 to 4 hours) to very brief (4 to 48 hours) Flooding frequency Frequent Ponding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Ponding frequency None to rare Elevation 3200 – 5000 ft Slope 0 – 2 % 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) 0 days 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 deep soils which have formed in clayey alluvium from basic igneous sources. They are very dark colored and have high shrink-swell potentials. Churning and cracking cause very rough surfaces. Plant-soil moisture relationships are very good due to extra water the site receives.
Soils mapped on this site include: SSA-665 Willcox area MU's Gt & Gu Guest; SSA-667 Santa Cruz area MU Gu Guest; SSA-669 Pima county eastern part MU 33 Guest; SSA-671 Cochise county Douglas-Tombstone part MU's 12 Bonita clay, 30 & 84 Guest, 54 Elfrida clay loam, 70 Bonita, 78 & 79 Guest silty clay loam, 81 Guest silty clay.Table 4. Representative soil features
Surface texture (1) Silty clay loam
Family particle size (1) Clayey
Drainage class Well drained Permeability class Slow to very slow Soil depth 60 in Surface fragment cover <=3" 0 – 10 % Surface fragment cover >3" 0 – 1 % Available water capacity
(0-40in)8.4 – 9.6 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)7.4 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 8 % Subsurface fragment volume >3"
(Depth not specified)0 – 1 % 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.
This plant community is tobosa grassland with a canopy cover from 45 to 75%. Vine mesquite occurs in patches on the site. The plant community has a diverse flora of native annual and perennial forbs as well as annual grasses. Periodic wildfires occurred, June thru August, and helped control shrubs encroaching from adjacent upland sites. Tobosa is a very poor seed producer and when reduced to canopy levels below 5%, may not be able to recover its dominance. Johnson grass and bermuda grass can invade areas of this site but never dominate and exist only in minor amounts if the site is grazed as they are much more palatable than Tobosa. Possible, exotic, invasive weeds on this site include; yellow and malta starthistle, and Russian and spotted knapweed.
State and transition model
Custom diagramStandard diagram
Figure 4. State and transition, Clayey Swale 12-16" 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
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe potential plant community on this site is dominated by warm season perennial grasses, mainly tobosa and vine mesquite. The major perennial grasses on the site are well dispersed over areas of the site. The aspect is open grassland.
With continuous heavy grazing, patches develop which are dominated by annual forbs and grasses. Also palatable forbs and vine mesquite are easily grazed out and replaced by annuals. Snakeweed, burroweed and mesquite can invade and become dominant on the site. Natural fire may have been important in development of the potential plant community.Figure 5. 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 840 1500 2200 Forb 40 100 200 Shrub/Vine 0 45 130 Total 880 1645 2530 Table 6. Soil surface cover
Tree basal cover 0-0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 10-30% Forb basal cover 0-0% Non-vascular plants 0-0% Biological crusts 0-10% Litter 30-70% Surface fragments >0.25" and <=3" 0-10% Surface fragments >3" 0-0% Bedrock 0% Water 0% Bare ground 10-20% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – – 0-5% 0-5% >0.5 <= 1 – 0-1% 10-20% 0-10% >1 <= 2 – 0-1% 30-60% 0-5% >2 <= 4.5 – 0-1% 5-10% 0-5% >4.5 <= 13 – 0-1% – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 6. 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 grassesTobosa canopy is reduced (less than 5%) due to the interactions of drought, heavy grazing and / or fire. In some circumstances the normal overland flow of water has been diverted by roads, drainage ditches and diversions. Some areas of this site have been created by cultivation for irrigated farming and subsequent abandonment. Native and non-native annual species dominate. Tobosa will not be able to re-colonize this state because cover is too low and patchy in distribution, and a lack of viable seed 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 activity and good hydrologic relationships.
State 3
Mesquite, native grassesCommunity 3.1
Mesquite, native grassesMesquite has invaded and occurs at canopy levels from 2 to 15%. Other shrubs may also occur. Fire has been excluded for long periods of time. Tobosa still dominates the under-story with annual forbs and grasses. Johnson grass and bermuda grass may be present in areas but will not dominate the state as long as it is grazed. Fires can burn through this community but mesquite is well established, it's root crowns protected by sediment accumulation, and it will sprout and quickly re-assume dominance.
State 4
Eroded stateCommunity 4.1
Eroded stateVery heavy traffic by livestock or machinery has caused persistent compaction. Diversion of overland flow and runoff water in farming areas may have caused rilling and gullies to form. Concentration of runoff by road and railroad culverts and bridges may also cause gullying. Some areas of this site are tributary to large bottoms that gullied at the turn of the century and base level changes in those systems have caused more recent gullying of the tributary bottoms. The soil profile no longer gets wet so the inherent, vertic, soil properties cannot act to maintain good tilth and promote infiltration of rainfall.
State 5
Tobosa unfloodedCommunity 5.1
Tobosa unfloodedThis state occurs where the natural flooding regime has been interrupted by the construction of dikes, levees and roads and drainages ditches. It is usually found in cultivated areas like the Sulphur Springs Valley. The new site potential is the same as for Clayey Upland # R041XC304AZ.
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 720–1500 tobosagrass PLMU3 Pleuraphis mutica 700–1100 – vine mesquite PAOB Panicum obtusum 50–200 – 2 Misc. perennial grasses 100–200 big sacaton SPWR2 Sporobolus wrightii 0–100 – sideoats grama BOCU Bouteloua curtipendula 0–100 – blue grama BOGR2 Bouteloua gracilis 0–100 – squirreltail ELEL5 Elymus elymoides 0–50 – cane bluestem BOBA3 Bothriochloa barbinodis 0–50 – curly-mesquite HIBE Hilaria belangeri 0–25 – green sprangletop LEDU Leptochloa dubia 0–25 – creeping muhly MURE Muhlenbergia repens 0–25 – whiplash pappusgrass PAVA2 Pappophorum vaginatum 0–25 – hairy grama BOHI2 Bouteloua hirsuta 0–25 – plains bristlegrass SEVU2 Setaria vulpiseta 0–25 – alkali sacaton SPAI Sporobolus airoides 0–25 – sand dropseed SPCR Sporobolus cryptandrus 0–15 – burrograss SCBR2 Scleropogon brevifolius 0–10 – Arizona cottontop DICA8 Digitaria californica 0–2 – 3 Perennial threeawns 10–50 spidergrass ARTE3 Aristida ternipes 0–25 – spidergrass ARTEG Aristida ternipes var. gentilis 0–20 – Fendler threeawn ARPUL Aristida purpurea var. longiseta 0–10 – Parish's threeawn ARPUP5 Aristida purpurea var. parishii 0–10 – poverty threeawn ARDI5 Aristida divaricata 0–5 – 4 Annual grasses 10–250 little barley HOPU Hordeum pusillum 1–100 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 1–100 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 1–100 – Mexican panicgrass PAHI5 Panicum hirticaule 0–50 – Arizona signalgrass URAR Urochloa arizonica 0–50 – sixweeks fescue VUOC Vulpia octoflora 1–50 – tapertip cupgrass ERACA Eriochloa acuminata var. acuminata 0–25 – sticky sprangletop LEVI5 Leptochloa viscida 0–25 – Arizona brome BRAR4 Bromus arizonicus 0–20 – prairie threeawn AROL Aristida oligantha 0–10 – needle grama BOAR Bouteloua aristidoides 0–5 – sixweeks grama BOBA2 Bouteloua barbata 0–5 – delicate muhly MUFR Muhlenbergia fragilis 0–5 – littleseed muhly MUMI Muhlenbergia microsperma 0–5 – witchgrass PACA6 Panicum capillare 0–5 – sixweeks threeawn ARAD Aristida adscensionis 0–5 – Mexican lovegrass ERME Eragrostis mexicana 0–5 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 0–5 – Bigelow's bluegrass POBI Poa bigelovii 0–5 – Forb5 Perennial Forbs 20–100 Missouri gourd CUFO Cucurbita foetidissima 0–25 – Cooley's bundleflower DECO2 Desmanthus cooleyi 0–25 – desert globemallow SPAM2 Sphaeralcea ambigua 0–25 – spear globemallow SPHA Sphaeralcea hastulata 1–20 – Indian rushpea HOGL2 Hoffmannseggia glauca 1–20 – Lewis flax LILE3 Linum lewisii 0–20 – dwarf desertpeony ACNA2 Acourtia nana 0–20 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 1–15 – bluedicks DICA14 Dichelostemma capitatum 1–15 – spreading fleabane ERDI4 Erigeron divergens 0–10 – scarlet spiderling BOCO Boerhavia coccinea 0–10 – small matweed GUDE Guilleminea densa 0–10 – largeflower onion ALMA4 Allium macropetalum 0–5 – Wright's cudweed PSCAC2 Pseudognaphalium canescens ssp. canescens 0–5 – New Mexico fanpetals SINE Sida neomexicana 0–5 – silverleaf nightshade SOEL Solanum elaeagnifolium 0–5 – Wright's deervetch LOWR Lotus wrightii 0–5 – brownfoot ACWR5 Acourtia wrightii 0–5 – southwestern mock vervain GLGO Glandularia gooddingii 0–5 – coyote gourd CUPA Cucurbita palmata 0–5 – whitemouth dayflower COER Commelina erecta 0–5 – leatherweed CRPO5 Croton pottsii 0–5 – fingerleaf gourd CUDI Cucurbita digitata 0–5 – white prairie aster SYFAC Symphyotrichum falcatum var. commutatum 0–5 – American vetch VIAM Vicia americana 0–5 – Louisiana vetch VILUL2 Vicia ludoviciana ssp. ludoviciana 0–5 – ivyleaf groundcherry PHHE4 Physalis hederifolia 0–3 – tuber anemone ANTU Anemone tuberosa 0–3 – twinleaf senna SEBA3 Senna bauhinioides 0–3 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 0–2 – variableleaf bushbean MAGI2 Macroptilium gibbosifolium 0–2 – slimleaf bean PHAN3 Phaseolus angustissimus 0–2 – orange fameflower PHAU13 Phemeranthus aurantiacus 0–2 – Greenman's biscuitroot LOGR2 Lomatium greenmanii 0–2 – Greene's bird's-foot trefoil LOGR4 Lotus greenei 0–2 – southwestern pricklypoppy ARPL3 Argemone pleiacantha 0–2 – lyreleaf greeneyes BELY Berlandiera lyrata 0–2 – trailing windmills ALIN Allionia incarnata 0–2 – desert mariposa lily CAKE Calochortus kennedyi 0–2 – sego lily CANU3 Calochortus nuttallii 0–2 – 6 Annual Forbs 20–100 common sunflower HEAN3 Helianthus annuus 1–100 – longleaf false goldeneye HELOA2 Heliomeris longifolia var. annua 1–50 – camphorweed HESU3 Heterotheca subaxillaris 1–50 – sensitive partridge pea CHNI2 Chamaecrista nictitans 1–50 – carelessweed AMPA Amaranthus palmeri 1–40 – morning-glory IPOMO Ipomoea 0–25 – spreading fanpetals SIAB Sida abutifolia 1–25 – tanseyleaf tansyaster MATA2 Machaeranthera tanacetifolia 1–25 – Nuttall's povertyweed MONU Monolepis nuttalliana 0–25 – Arizona popcornflower PLAR Plagiobothrys arizonicus 0–25 – intermediate pepperweed LEVIM Lepidium virginicum var. medium 0–20 – goosefoot CHENO Chenopodium 1–20 – wheelscale saltbush ATEL Atriplex elegans 0–15 – crestrib morning-glory IPCO2 Ipomoea costellata 0–15 – slender goldenweed MAGR10 Machaeranthera gracilis 1–15 – woolly plantain PLPA2 Plantago patagonica 0–15 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–10 – western tansymustard DEPI Descurainia pinnata 1–10 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–10 – Arizona poppy KAGR Kallstroemia grandiflora 0–10 – Coulter's spiderling BOCO2 Boerhavia coulteri 0–10 – bristly fiddleneck AMTE3 Amsinckia tessellata 0–10 – milkvetch ASTRA Astragalus 0–10 – scrambled eggs COAU2 Corydalis aurea 0–5 – hoary bowlesia BOIN3 Bowlesia incana 0–5 – fringed redmaids CACI2 Calandrinia ciliata 0–5 – New Mexico copperleaf ACNE Acalypha neomexicana 0–5 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–5 – spurge EUPHO Euphorbia 1–5 – Lemmon's linanthus LELE29 Leptosiphon lemmonii 0–5 – wedgeleaf draba DRCU Draba cuneifolia 0–5 – miniature woollystar ERDI2 Eriastrum diffusum 0–5 – spreading fleabane ERDI4 Erigeron divergens 0–5 – sorrel buckwheat ERPO4 Eriogonum polycladon 0–5 – golden crownbeard VEEN Verbesina encelioides 0–5 – sleepy silene SIAN2 Silene antirrhina 0–5 – sawtooth sage SASU7 Salvia subincisa 0–5 – ragwort SENEC Senecio 0–5 – doubleclaw PRPA2 Proboscidea parviflora 0–5 – star gilia GIST Gilia stellata 0–5 – desert Indianwheat PLOV Plantago ovata 0–5 – green carpetweed MOVE Mollugo verticillata 0–5 – foothill deervetch LOHU2 Lotus humistratus 0–5 – coastal bird's-foot trefoil LOSAB Lotus salsuginosus var. brevivexillus 0–5 – Arizona lupine LUAR4 Lupinus arizonicus 0–5 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–5 – hollowleaf annual lupine LUSU3 Lupinus succulentus 0–5 – American wild carrot DAPU3 Daucus pusillus 0–4 – Arizona blanketflower GAAR2 Gaillardia arizonica 0–3 – Goodding's bladderpod LEGO2 Lesquerella gooddingii 0–2 – plains flax LIPU4 Linum puberulum 0–2 – Texas stork's bill ERTE13 Erodium texanum 0–2 – sacred thorn-apple DAWR2 Datura wrightii 0–2 – manybristle chinchweed PEPA2 Pectis papposa 0–2 – New Mexico plumeseed RANE Rafinesquia neomexicana 0–2 – desert unicorn-plant PRAL4 Proboscidea althaeifolia 0–2 – Fendler's desertdandelion MAFE Malacothrix fendleri 0–1 – Shrub/Vine7 Miscellaneous shrubs 0–40 western honey mesquite PRGLT Prosopis glandulosa var. torreyana 0–20 – velvet mesquite PRVE Prosopis velutina 0–20 – fourwing saltbush ATCA2 Atriplex canescens 0–10 – whitethorn acacia ACCO2 Acacia constricta 0–10 – pale desert-thorn LYPA Lycium pallidum 0–10 – catclaw mimosa MIACB Mimosa aculeaticarpa var. biuncifera 0–10 – catclaw acacia ACGR Acacia greggii 0–5 – knifeleaf condalia COSP3 Condalia spathulata 0–5 – littleleaf sumac RHMI3 Rhus microphylla 0–5 – Warnock's snakewood COWA Condalia warnockii 0–3 – American tarwort FLCE Flourensia cernua 0–2 – winterfat KRLA2 Krascheninnikovia lanata 0–2 – lotebush ZIOB Ziziphus obtusifolia 0–2 – 8 Half shrubs 0–50 broom snakeweed GUSA2 Gutierrezia sarothrae 0–20 – burroweed ISTE2 Isocoma tenuisecta 0–20 – bastardsage ERWR Eriogonum wrightii 0–15 – yerba de pasmo BAPT Baccharis pteronioides 0–10 – fairyduster CAER Calliandra eriophylla 0–5 – threadleaf snakeweed GUMI Gutierrezia microcephala 0–5 – 9 Succulents 0–40 dollarjoint pricklypear OPCH Opuntia chlorotica 0–15 – cactus apple OPEN3 Opuntia engelmannii 0–15 – tulip pricklypear OPPH Opuntia phaeacantha 0–10 – Christmas cactus CYLE8 Cylindropuntia leptocaulis 0–10 – walkingstick cactus CYSP8 Cylindropuntia spinosior 0–10 – banana yucca YUBA Yucca baccata 0–5 – soaptree yucca YUEL Yucca elata 0–5 – candy barrelcactus FEWI Ferocactus wislizeni 0–2 – sacahuista NOMI Nolina microcarpa 0–2 – spinystar ESVI2 Escobaria vivipara 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 (%) Table 12. Community 5.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Herbaceous forage produced on this site is best used in the summer rainy season when tobosa is green and growing. Large areas of the site should be fenced exclusively to best manage the forage resource. Care must be taken to avoid overgrazing of more palatable species associated with tobosa on the site. Burning or mowing can be used to freshen old growth tobosa grass. Burning should be done in years with good winter-spring rainfall and, then in late February or March. Spring re-growth should be rested until the onset of summer rains. Tobosa can be cut and baled for fair quality hay. Summer growth should be cut in full flower, left to dry one day, and baled the next day for best quality.
Dormant tobosa is very unpalatable.
This site is mainly a foraging area for large wildlife species. Free water is usually available in the summer rainy season in natural charcos and discontinued gullies. Being open grassland, the site is home to a variety of small herbivores and their associated predators.Hydrological functions
Due to severe soil cracking and churning (producing rough and porous surfaces), this site has very high infiltration rates when dry. Vertic soil properties eliminate most surface compaction 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 on this site due to clayey soils. Invaded areas may have limited fuel-wood but nothing big enough for posts or stays.
Other products
Clay
Supporting information
Inventory data references
Range 417s include 3 in excellent condition and 1 in good condition.
Type locality
Location 1: Cochise County, AZ Township/Range/Section T17S R27E S5 Location 2: Pima County, AZ Township/Range/Section T19S R17E S29 General legal description Enzenberg Pasture, Empire Ranch, Empire-Cienega National Conservation Area Contributors
Dan Robinett
Larry D. Ellicott
Steve Barker
Unknown
Wilma RenkenRangeland 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, Emilio Carrillo Contact for lead author NRCS Tucson Area Office Date 03/04/2005 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:
None present due to high shrink/swell soils. -
Number and height of erosional pedestals or terracettes:
No pedestals due to high shrink/swell soils. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-10% -
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 stay in place. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Expect values of 4-6 across site. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
fine subangular blocky to massive; Color is 10YR5/2 Dry, 10YR2/2 Moist; thickness to 5 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Cover estimated as follows: Canopy 80%, Basal 35%, Litter 15%; 95% of canopy cover is perennial midgrasses, 3% is short grasses, and 2 % is grass like and forbs. Short grass species cover occupy scattered patches 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. -
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:
perennial forbs = shrubs & trees = annual forbs & grassesOther:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Approximately 50% of basal cover of midgrass species lost in recent prolonged drought -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
800 lbs/acreunfavorable precipitation; 2,000 lbs/acre normal precipitation; 2,500 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:
mesquite, bermuda grass, Johnson grass. -
Perennial plant reproductive capability:
Not affected even following several years of prolonged drought period for region.
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