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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): 040X–Sonoran Basin and Range
AZ 40.1 – Upper Sonoran Desert
Elevations range from 2000 to 3200 feet and precipitation averages 10 to 13 inches per year. Vegetation includes saguaro, palo verde, mesquite, creosotebush, triangle bursage, prickly pear, cholla, limberbush, wolfberry, bush muhly, threeawns, ocotillo, and globe mallow. 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.Classification relationships
Similar to TES mapping unit 287 on the Tonto National Forest. Tonto basin.
Associated sites
R040XA114AZ Loamy Upland 10"-13" p.z.
R040XA115AZ Sandy Wash 10"-13" p.z.
R040XA117AZ Sandy Loam Upland, Deep 10"-13" p.z.
Similar sites
R041XB215AZ Sandy Loam Upland 8-12" p.z.
R041XC319AZ Sandy Loam Upland 12-16" p.z.
Table 1. Dominant plant species
Tree (1) Parkinsonia microphylla
(2) Prosopis velutinaShrub (1) Ambrosia deltoidea
(2) Isocoma tenuisectaHerbaceous (1) Muhlenbergia porteri
(2) Aristida ternipesPhysiographic features
This site occurs in the upper elevations of the Sonoran Desert in southern Arizona. It occurs on fan terraces and old stream terraces.
Table 2. Representative physiographic features
Landforms (1) Fan
(2) Terrace
(3) Stream terrace
Flooding frequency None Ponding frequency None Elevation 1900 – 3300 ft Slope 1 – 15 % Aspect Aspect is not a significant factor Climatic features
Precipitation in the sub resource area ranges from 10 to 13 inches in the southern part, along the Mexican border with elevations from about 1900 to 3200 feet. Precipitation in the northern part of the resource area ranges from 11 to 14 inches with elevations from about 1700 to 3500 feet. Winter-summer rainfall ratios range from 40%-60% in the southern portions of the land resource unit, to 50%-50% in the central portions, to 60%-40% in the northern part of the land resource unit. As one moves from east to west in this resource area rains become slightly more unpredictable and variable with Coefficients of Variation of annual rainfall equal to 29% at Tucson and 36% at Carefree. Summer rains fall July through Sept., originate in the Gulf of Mexico, and are convective, usually brief, intense thunderstorms. Cool season moisture tends to be frontal, originating in the Pacific and Gulf of California. This winter precipitation falls in widespread storms with long duration and low intensity. Snow is rare and seldom lasts more than an hour or two. May and June are the driest months of the year. Humidity is generally very low.
Winter temperatures are mild, with very few days recording freezing temperatures in the morning. Summer temperatures are warm to hot, with several days in June and July exceeding 105 degrees F.
Both the spring and the summer growing seasons are equally important for perennial grass, forb and shrub growth. Cool and warm season annual forbs and grasses can be common in their respective seasons with above average rainfall. Perennial forage species can remain green throughout the year with available moisture.Table 3 Representative climatic features
Frost-free period (average) 270 days Freeze-free period (average) 0 days Precipitation total (average) 10 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 loamy alluvium of mixed origins. Surface textures range from sandy loam to very gravelly sandy loam and must be as thick or thicker than four inches (eight inches for GRV-SL). These soils have clayey horizons at shallow depths (either argillic or cambic). Plant-soil moisture relationships are very good.
Soils mapped on this site include:
SSA-627 Southern Mohave County MU Amole-5;
SSA-645 Aguila-Carefree area MU's Gila-54 & Vado-122;
SSA-659 Western Pinal County Sonoita-35;
SSA-668 Tucson-Avra Valley area MU's Anway-At, Grabe-GgB, Sonoita-AsB, PaB, SmA, SmB, StB & VnB, Tubac-StB, TtA, TtB & TxB, Valencia-CvB, VaA, VaB, VcB, VgB & VnB;
SSA-669 Eastern Pima County MU's Bucklebar-8 & 29, Sahuarita-8, 36 & 55, Tubac-80 & 82 and
SSA-703 Tohono O'odham area MU's Bucklebar-6 & Tubac-58.Table 4. Representative soil features
Surface texture (1) Sandy loam
(2) Gravelly sandy loam
(3) Very 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 – 10 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 2 Soil reaction (1:1 water)
(0-40in)6.6 – 7.8 Subsurface fragment volume <=3"
(Depth not specified)5 – 55 % Subsurface fragment volume >3"
(Depth not specified)0 – 5 % 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
Custom diagramStandard diagram
Figure 4. State and Transition, Sandyloam upland 10-13" pz.
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 6 submodel, plant communities
State 7 submodel, plant communities
State 1
Historical Climax Plant CommunityCommunity 1.1
Historical Climax Plant CommunityThe potential plant community is an open stand of desert trees with a shrub, cacti and grass understory. The major grass species are well dispersed throughout the plant community. The aspect is savannah.
With continuous, heavy grazing, perennial grasses and suffrutescent forb species are removed from the plant community and shrubs like; triangle bursage, burroweed, and snakeweed, can increase to dominate the understory. With thick, coarse textured soil surfaces, trees can reach moderate size on the site. A tree canopy of 5 to 10% is important on the site to keep diversity in the plant community. The potential of the site to produce grass is reduced as tree cover exceeds these amounts. Triangle bursage understories are long lived, persistent, and will not easily be replaced by perennial grass (as will burroweed understories) with good grazing management. In severe drought the cover of perennial grasses and herbs as well as bursage and burroweed can be greatly reduced in the plant community. Recovery can go back to perennial grasses and herbs if good summer rains follow drought. Recovery can go back to the half shrubs if good cool season rains follow the drought. Jumping cholla can increase with heavy grazing or increases can be episodic due to climate. Stand lifespans can range from 40-60 years without reproduction. Prickley pear can also increase under heavy grazing pressure.
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 50 400 770 Forb 5 100 220 Tree 100 150 200 Shrub/Vine 20 100 150 Total 175 750 1340 Table 6. Soil surface cover
Tree basal cover 0-0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 0-10% Forb basal cover 0-0% Non-vascular plants 0% Biological crusts 10-20% Litter 20-90% Surface fragments >0.25" and <=3" 0-60% 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 – 0-1% 0-30% 0-15% >0.5 <= 1 – 0-5% 1-25% 0-10% >1 <= 2 – 1-15% 1-10% 0-1% >2 <= 4.5 0-1% 0-2% 0-5% 0-1% >4.5 <= 13 5-10% – – – >13 <= 40 0-1% – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 6. Plant community growth curve (percent production by month). AZ4013 , 40.1 10-13" p.z. other sites. Growth begins in the late winter, goes semi-dormant in the drought period of late May through early July, growth continues in the summer through early fall..
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 5 10 20 15 0 5 20 15 5 5 0 State 2
Exotic perennial grasses or Euryops with nativesCommunity 2.1
Exotic perennial grasses or Euryops with nativesThis community occurs where bufflegrass, Lehmann lovegrass, Boer lovegrass, natal grass, fountain grass or the African shrubs Euryops multifidus and Pentzia incana invade the native plant community. These species occupy the niches of perennial grasses like bush muhly, spidergrass threeawn, Arizona cottontop and low shrubs like burroweed and triangle bursage.
State 3
Exotic perennial grasses and fireCommunity 3.1
Exotic perennial grasses and fireThis community occurs where a native plant community that has been invaded by bufflegrass, Lovegrasses or fountain grass has burned one or more times. Increasing amounts of exotic perennial grasses leads to more uniform fine fuels. In areas adjacent to roads and urban areas the risk of repeated fires will increase. As fire frequency increases the dominance of the exotic grasses increase.
State 4
Exotic annualsCommunity 4.1
Exotic annualsThis plant community occurs where the native plant community has been invaded by annuals like schismus, red brome and filaree. These species occupy the niche of the native winter annual forbs and grasses. The exotic annual grasses will fluctuate from nearly nothing in a dry winter to dominance of the understory plant community in a El Nino winter.
State 5
Annuals, half shrubs and fireCommunity 5.1
Annuals, half shrubs and fireThis plant community occurs as a result of a single hot season fire. Paloverde, ironwood, cacti and saguaro can be severely impacted and may take long periods of time (30-50 years) to recover to pre-fire levels. Mesquite (except the very old trees and the very young) will sprout after fire. Perennial and annual grasses and forbs dominate the community for some time until shrubs like bursage can recover. Perennial grasses can recover rapidly if grazing pressure is low and summer rains are sufficient.
This plant community can produce enough herbaceous fuel from native species of grasses and / or forbs to carry fire in El Nino years or after unusually wet summers. The natural incidence of fire in this MLRA is very low and fires are much more common from man-made ignitions. Areas of the site close to urban zones or along heavily travelled roads and highways will experience a higher rate of fires.State 6
Annuals and fireCommunity 6.1
Annuals and fireThis plant community occurs where a native plant community has burned repeatedly. As fires become more frequent the native trees, shrubs and succulents are removed from the plant community and annuals becomes dominant. In areas of the site near urban areas and along heavily travelled roads this will be a more common occurence due to an increased source of ignitions.
This can occur both in areas with only native annuals species present as well as those which have been invaded by schismus and red brome.State 7
HCPC 2 - Saguaro stateCommunity 7.1
HCPC 2 - Saguaro stateThere is a 300 year cycle on this site that swings between dominance of native trees and large shrubs (that serve as nurse plants) and mature saguaro forest. Saguaros establish wholesale in very favorable years (El Nino years like 1983) only in the presence of plentiful nurse plants like paloverde, ironwood, mesquite, wolfberry, creosote and jojoba. As saguaro plants top their nurse plants (40-60 years) the trees and shrubs begin to die. Saguaro stands reach maturity at 150 to 200 years and begin to diminish over the next 100 years as the large shrubs and trees come back into the plant community.
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Short lived perennial grasses 10–160 Rothrock's grama BORO2 Bouteloua rothrockii 10–150 – Parry's grama BOPA2 Bouteloua parryi 0–100 – slender grama BORE2 Bouteloua repens 0–40 – 2 Dominant mid grasses 20–200 Arizona cottontop DICA8 Digitaria californica 5–100 – whiplash pappusgrass PAVA2 Pappophorum vaginatum 0–100 – purple threeawn ARPU9 Aristida purpurea 0–50 – spidergrass ARTE3 Aristida ternipes 5–45 – spidergrass ARTEG Aristida ternipes var. gentilis 0–25 – Parish's threeawn ARPUP5 Aristida purpurea var. parishii 0–20 – tanglehead HECO10 Heteropogon contortus 0–20 – plains bristlegrass SEVU2 Setaria vulpiseta 0–20 – big galleta PLRI3 Pleuraphis rigida 0–10 – large-spike bristlegrass SEMA5 Setaria macrostachya 0–3 – 3 Dominant suffrutescent grasses 10–150 bush muhly MUPO2 Muhlenbergia porteri 5–100 – Santa Rita threeawn ARCAG Aristida californica var. glabrata 1–50 – black grama BOER4 Bouteloua eriopoda 0–40 – 4 Miscellaneous perennial grasses 0–10 cane bluestem BOBA3 Bothriochloa barbinodis 0–5 – sand dropseed SPCR Sporobolus cryptandrus 0–5 – mesa dropseed SPFL2 Sporobolus flexuosus 0–2 – slim tridens TRMU Tridens muticus 0–2 – low woollygrass DAPU7 Dasyochloa pulchella 0–2 – Indian ricegrass ACHY Achnatherum hymenoides 0–2 – nineawn pappusgrass ENDE Enneapogon desvauxii 0–2 – spike dropseed SPCO4 Sporobolus contractus 0–1 – desert needlegrass ACSP12 Achnatherum speciosum 0–1 – squirreltail ELELE Elymus elymoides ssp. elymoides 0–1 – sideoats grama BOCU Bouteloua curtipendula 0–1 – 5 Annual grasses 10–250 needle grama BOAR Bouteloua aristidoides 5–150 – sixweeks grama BOBA2 Bouteloua barbata 0–50 – Mexican panicgrass PAHI5 Panicum hirticaule 0–50 – sixweeks threeawn ARAD Aristida adscensionis 0–50 – prairie threeawn AROL Aristida oligantha 1–50 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 0–25 – sixweeks fescue VUOC Vulpia octoflora 0–25 – feather fingergrass CHVI4 Chloris virgata 0–25 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 0–10 – tufted lovegrass ERPEP2 Eragrostis pectinacea var. pectinacea 0–10 – Bigelow's bluegrass POBI Poa bigelovii 0–10 – bearded cupgrass ERAR5 Eriochloa aristata 0–5 – witchgrass PACA6 Panicum capillare 0–5 – canyon cupgrass ERLE7 Eriochloa lemmonii 0–2 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 0–2 – Madagascar dropseed SPPY2 Sporobolus pyramidatus 0–2 – Arizona signalgrass URAR Urochloa arizonica 0–2 – delicate muhly MUFR Muhlenbergia fragilis 0–2 – littleseed muhly MUMI Muhlenbergia microsperma 0–2 – Arizona brome BRAR4 Bromus arizonicus 0–1 – Forb6 Perennial forbs 2–20 desert globemallow SPAM2 Sphaeralcea ambigua 1–10 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 1–5 – Coues' cassia SECO10 Senna covesii 0–5 – lacy tansyaster MAPIP4 Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida 1–5 – wishbone-bush MILAV Mirabilis laevis var. villosa 0–2 – evening primrose OENOT Oenothera 0–2 – slender poreleaf POGR5 Porophyllum gracile 0–2 – whitemargin sandmat CHAL11 Chamaesyce albomarginata 0–2 – spreading fleabane ERDI4 Erigeron divergens 0–2 – wild dwarf morning-glory EVAR Evolvulus arizonicus 0–2 – desert lily HEUN2 Hesperocallis undulata 0–2 – slender janusia JAGR Janusia gracilis 0–2 – smooth threadleaf ragwort SEFLM Senecio flaccidus var. monoensis 0–2 – spreading fanpetals SIAB Sida abutifolia 0–2 – New Mexico silverbush ARNE2 Argythamnia neomexicana 0–2 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 0–2 – Coulter's wrinklefruit TECO Tetraclea coulteri 0–1 – catnip noseburn TRNE Tragia nepetifolia 0–1 – Watson's dutchman's pipe ARWA Aristolochia watsonii 0–1 – dense ayenia AYMI Ayenia microphylla 0–1 – desert marigold BAMU Baileya multiradiata 0–1 – climbing wartclub BOSC Boerhavia scandens 0–1 – shrubby purslane POSU3 Portulaca suffrutescens 0–1 – canaigre dock RUHY Rumex hymenosepalus 0–1 – twinleaf senna SEBA3 Senna bauhinioides 0–1 – silverleaf nightshade SOEL Solanum elaeagnifolium 0–1 – field anoda ANPE4 Anoda pentaschista 0–1 – dwarf desertpeony ACNA2 Acourtia nana 0–1 – brownfoot ACWR5 Acourtia wrightii 0–1 – San Felipe dogweed ADPO Adenophyllum porophylloides 0–1 – ragged nettlespurge JAMA Jatropha macrorhiza 0–1 – whitemouth dayflower COER Commelina erecta 0–1 – leatherweed CRPOP Croton pottsii var. pottsii 0–1 – fingerleaf gourd CUDI Cucurbita digitata 0–1 – coyote gourd CUPA Cucurbita palmata 0–1 – Arizona wrightwort CAAR7 Carlowrightia arizonica 0–1 – orange fameflower PHAU13 Phemeranthus aurantiacus 0–1 – 7 Annual forbs 1–200 bristly fiddleneck AMTE3 Amsinckia tessellata 0–50 – Coulter's spiderling BOCO2 Boerhavia coulteri 0–50 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–50 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–50 – combseed PECTO Pectocarya 1–50 – Arizona phacelia PHAR13 Phacelia arizonica 0–25 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–25 – Arizona poppy KAGR Kallstroemia grandiflora 0–25 – thelypody THELY Thelypodium 0–25 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–25 – desert Indianwheat PLOV Plantago ovata 0–20 – miniature woollystar ERDI2 Eriastrum diffusum 0–20 – wheelscale saltbush ATEL Atriplex elegans 0–20 – pitseed goosefoot CHBE4 Chenopodium berlandieri 0–20 – milkvetch ASTRA Astragalus 0–15 – western tansymustard DEPI Descurainia pinnata 0–15 – mesa tansyaster MATA Machaeranthera tagetina 0–15 – tanseyleaf tansyaster MATA2 Machaeranthera tanacetifolia 0–10 – Gordon's bladderpod LEGO Lesquerella gordonii 0–10 – Texas stork's bill ERTE13 Erodium texanum 0–10 – cryptantha CRYPT Cryptantha 0–10 – buckwheat ERIOG Eriogonum 0–10 – carelessweed AMPA Amaranthus palmeri 0–10 – Tucson Mountain spiderling BOME Boerhavia megaptera 0–10 – Esteve's pincushion CHST Chaenactis stevioides 0–5 – American wild carrot DAPU3 Daucus pusillus 0–5 – manybristle chinchweed PEPA2 Pectis papposa 0–5 – Arizona lupine LUAR4 Lupinus arizonicus 0–5 – Arizona popcornflower PLAR Plagiobothrys arizonicus 0–5 – purslane PORTU Portulaca 0–5 – sleepy silene SIAN2 Silene antirrhina 0–5 – Coulter's globemallow SPCO2 Sphaeralcea coulteri 0–5 – New Mexico thistle CINE Cirsium neomexicanum 0–3 – hoary bowlesia BOIN3 Bowlesia incana 0–3 – hyssopleaf sandmat CHHY3 Chamaesyce hyssopifolia 0–2 – sensitive partridge pea CHNI2 Chamaecrista nictitans 0–2 – pricklyburr DAIN2 Datura inoxia 0–2 – common woolly sunflower ERLA6 Eriophyllum lanatum 0–2 – Mexican fireplant EUHE4 Euphorbia heterophylla 0–2 – hairy desertsunflower GECA2 Geraea canescens 0–2 – star gilia GIST Gilia stellata 0–2 – slimjim bean PHFI3 Phaseolus filiformis 0–2 – green carpetweed MOVE Mollugo verticillata 0–2 – Arizona cottonrose LOAR12 Logfia arizonica 0–2 – coastal bird's-foot trefoil LOSA Lotus salsuginosus 0–2 – slender goldenweed MAGR10 Machaeranthera gracilis 0–2 – doubleclaw PRPA2 Proboscidea parviflora 0–2 – sand fringepod THCU Thysanocarpus curvipes 0–2 – New Mexico plumeseed RANE Rafinesquia neomexicana 0–1 – lyreleaf jewelflower STCAA Streptanthus carinatus ssp. arizonicus 0–1 – woolly plantain PLPA2 Plantago patagonica 0–1 – Florida pellitory PAFL3 Parietaria floridana 0–1 – desert trumpet ERIN4 Eriogonum inflatum 0–1 – hairy prairie clover DAMO Dalea mollis 0–1 – Palmer's spectaclepod DICA31 Dimorphocarpa candicans 0–1 – desert thorn-apple DADI2 Datura discolor 0–1 – prostrate sandmat CHPR6 Chamaesyce prostrata 0–1 – milkweed ASCLE Asclepias 0–1 – desert sand verbena ABVI Abronia villosa 0–1 – trailing windmills ALIN Allionia incarnata 0–1 – common fiddleneck AMMEI2 Amsinckia menziesii var. intermedia 0–1 – Shrub/Vine8 Dominant half shrubs 5–95 triangle bur ragweed AMDE4 Ambrosia deltoidea 0–50 – burroweed ISTE2 Isocoma tenuisecta 1–50 – desert zinnia ZIAC Zinnia acerosa 1–30 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–10 – rough menodora MESC Menodora scabra 0–1 – buckwheat ERIOG Eriogonum 0–1 – 9 Miscellaneous shrubs 0–10 Thurber's penstemon PETH3 Penstemon thurberi 0–5 – shortleaf baccharis BABR Baccharis brachyphylla 0–3 – Eastern Mojave buckwheat ERFA2 Eriogonum fasciculatum 0–2 – narrowleaf goldenbush ERLI6 Ericameria linearifolia 0–2 – San Felipe dogweed ADPO Adenophyllum porophylloides 0–2 – burrobush AMDU2 Ambrosia dumosa 0–2 – snakewood CONDA Condalia 0–2 – littleleaf ratany KRER Krameria erecta 0–2 – winterfat KRLA2 Krascheninnikovia lanata 0–2 – Goodding's tansyaster MAPIG Machaeranthera pinnatifida ssp. gooddingii 0–2 – Mexican bladdersage SAME Salazaria mexicana 0–2 – jojoba SICH Simmondsia chinensis 0–2 – turpentinebroom THMO Thamnosma montana 0–2 – American threefold TRCA8 Trixis californica 0–1 – banana yucca YUBA Yucca baccata 0–1 – lacy tansyaster MAPIP4 Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida 0–1 – white ratany KRGR Krameria grayi 0–1 – whitestem paperflower PSCO2 Psilostrophe cooperi 0–1 – rayless goldenhead ACSP Acamptopappus sphaerocephalus 0–1 – bastardsage ERWR Eriogonum wrightii 0–1 – Nevada jointfir EPNE Ephedra nevadensis 0–1 – longleaf jointfir EPTR Ephedra trifurca 0–1 – yerba de pasmo BAPT Baccharis pteronioides 0–1 – Coulter's brickellbush BRCO Brickellia coulteri 0–1 – fairyduster CAER Calliandra eriophylla 0–1 – 10 Large shrubs 1–20 fourwing saltbush ATCA2 Atriplex canescens 0–5 – creosote bush LATRT Larrea tridentata var. tridentata 0–5 – ocotillo FOSP2 Fouquieria splendens 0–2 – Berlandier's wolfberry LYBE Lycium berlandieri 0–2 – Arizona desert-thorn LYEX Lycium exsertum 0–2 – cattle saltbush ATPO Atriplex polycarpa 0–2 – spiny hackberry CEEH Celtis ehrenbergiana 0–2 – catclaw acacia ACGR Acacia greggii 0–2 – Warnock's snakewood COWA Condalia warnockii 0–1 – whitethorn acacia ACCO2 Acacia constricta 0–1 – lotebush ZIOB Ziziphus obtusifolia 0–1 – sangre de cristo JACA2 Jatropha cardiophylla 0–1 – water jacket LYAN Lycium andersonii 0–1 – 11 Succulents 5–25 saguaro CAGI10 Carnegiea gigantea 1–15 – cactus apple OPEN3 Opuntia engelmannii 1–10 – tulip pricklypear OPPH Opuntia phaeacantha 0–5 – staghorn cholla CYVE3 Cylindropuntia versicolor 0–5 – candy barrelcactus FEWI Ferocactus wislizeni 1–5 – Arizona pencil cholla CYAR14 Cylindropuntia arbuscula 0–2 – jumping cholla CYFU10 Cylindropuntia fulgida 0–2 – purple pricklypear OPMA8 Opuntia macrocentra 0–2 – soaptree yucca YUEL Yucca elata 0–2 – walkingstick cactus CYSP8 Cylindropuntia spinosior 0–2 – Santa Rita pricklypear OPSA Opuntia santa-rita 0–1 – nightblooming cereus PEGR3 Peniocereus greggii 0–1 – Christmas cactus CYLE8 Cylindropuntia leptocaulis 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 – spinystar ESVIV Escobaria vivipara var. vivipara 0–1 – long-tubercle beehive cactus COROR Coryphantha robustispina ssp. robustispina 0–1 – buck-horn cholla CYAC8 Cylindropuntia acanthocarpa 0–1 – Tree14 Trees 100–200 yellow paloverde PAMI5 Parkinsonia microphylla 50–150 – velvet mesquite PRVE Prosopis velutina 50–100 – desert ironwood OLTE Olneya tesota 0–50 – blue paloverde PAFL6 Parkinsonia florida 0–15 – Joshua tree YUBR Yucca brevifolia 0–2 – 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 (%) Table 13. Community 6.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 14. Community 7.1 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 by all classes of livestock at any season. Forage species grow year-round with available moisture. Due to thick, coarse-textured surfaces, which can absorb intense rainfall, and clayey horizons below, which can slowly release this moisture to plants, this site has a longer green season than other, coarse textured sites. The plant community on this site provides adequate nutrition for livestock throughout the year.
Water developments are very important to wildlife species on this site. Vegetative cover and forage diversity are good enough for a great variety of wildlife including the large mammals.Hydrological functions
This site has coarse textured soil surfaces and low gradient slopes and is a poor producer of runoff.
Recreational uses
Hunting, horseback riding, hiking, photography, birdwatching, camping
Wood products
Mesquite furnishes limited firewood. In freeze free areas dead ironwood trees furnish wood for hobby uses and firewood.
Other products
Saguaro ribs, cholla skeletons, prickly pear tunas and pads, cholla buds and mesquite beans.
Supporting information
Inventory data references
Range 417s include 2 in good condition.
Type locality
Location 1: Pima County, AZ Township/Range/Section T16S R7E S3 General legal description Sells Field Office - Tribal Herd Ranch Location 2: Pima County, AZ Township/Range/Section T17S R9E S30 General legal description Palo Alto ranch, NW corner of West pasture Location 3: Pima County, AZ Township/Range/Section T15S R9E S1 General legal description La Tortuga Ranch, Tortuga pasture, Transect location T-6. Ungrazed 18 years. Contributors
C.Michaels
Dan Robinett
Larry D. Ellicott
M.G.LamerouxRangeland 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, Tom Reis, Emilio Carrillo Contact for lead author NRCS Tucson Area Office Date 02/08/2005 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
Infrequent, 40-60 feet apart, not well defined. -
Presence of water flow patterns:
Fairly common, cover approximately 10% of the area; approximately 30-50 feet in length before hitting an obstruction. -
Number and height of erosional pedestals or terracettes:
Most perennial grass and shrub plants have accumulated pedestals 1-2 inches in height, respectively. Terrecettes are 15-20 feet apart along water flow paths with a 2-inch elevation difference from above to below the terracete. Terracettes are not as stable as those observed in 12-16" pz, in that they are breached more often on this site. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
40-45%; some areas have higher cover on gentler slopes and lower cover on steeper slopes. -
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):
Herbaceous litter transported in water flow paths 30-50 feet in length and herbaceous litter moving from bare soil areas. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
No slake test done. Expect ratings of 2-3 in bare areas, and 4-5 under shrub and perennial grass canopies. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Weak angular to subangular blocky; color is 10YR7/3 dry, 10YR5/3 moist; thickness to 13 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
30% canopy cover of large shrubs, succulents, half shrubs and grasses; 50-55% litter cover; approximately 2.5% basal cover; 25% of cover is perennial grasses; 30% of cover is trees and shrubs; cover is well dispersed throughout the site. Note: reference area has a higher cover of mesquite than expected for the site. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
No compaction layer on this site; bare soil areas have thin laminar crust from raindrop impact; penetrometer tests with weight drop distance from top of weight to top of impact ring = 2.24 feet were: average = 3.92 inches, s.d. = 1.19 inches. Tests outside IBP exclosure on SRER were average = 2.17, s.d. = 0.4. -
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 shrubs (mesquite #1, desert hackberry #2, blue paloverde #3, and mormon tea) > perennial grasses > succulents > half shrubs = annual forbs & grasses.Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Approximately 50% basal cover of perennial grass species and 50% basal cover of sub shrub species has been lost due to 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):
175 lbs/ac unfavorable precipitation; 750 lbs/ac normal precipitation; 1340 lbs/ac favorable precipitaton. -
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, Opuntia, burroweed, & snakeweed are increasing not invading. Bufflegrass and Lehmann lovegrass. -
Perennial plant reproductive capability:
Not affected even following several years of drought period for the region. Good age class distribution of plants.
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