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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.Associated sites
R040XA102AZ Clayey Swale 10"-13" p.z.
R040XA108AZ Limy Fan 10"-13" p.z.
R040XA110AZ Limy Slopes 10"-13" p.z.
R040XA114AZ Loamy Upland 10"-13" p.z.
Similar sites
R041XC311AZ Loamy Swale 12-16" p.z.
R040XB211AZ Loamy Swale 7"-10" p.z.
R041XB209AZ Loamy Swale 8-12" p.z.
Table 1. Dominant plant species
Tree (1) Prosopis velutina
Shrub (1) Acacia constricta
Herbaceous (1) Pappophorum vaginatum
(2) Panicum obtusumPhysiographic features
This site occurs in the upper elevations of the Sonoran Desert in southern Arizona. It benefits on a regular basis from extra moisture received as overbank flooding and/or runoff from adjacent upland sites. It occurs on flood plains and alluvial fans.
Table 2. Representative physiographic features
Landforms (1) Flood plain
(2) Alluvial fan
(3) Stream terrace
Flooding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Flooding frequency Rare to occasional Ponding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Ponding frequency None to rare Elevation 1850 – 3300 ft Slope 0 – 2 % 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, young soils on loamy alluvium from mixed sources. They may or may not be calcareous, and have low shrink-swell potential. Plant-soil moisture relationships are excellent.
Soils on mapped on this site include:
SSA-668 Tucson-Avra Valley area MU's Aqua-Ag, Anthony-Ao, Estrella-Ts3, Gila-Ga, GbA, Ge, Glendale-Gd, Ge, Ge3, Grabe-Gh, GkA, Gm, GoB, Gullied Land-Gu, Pima-Pm, Trix-Tr & Ts3;
SSA-669 Eastern Pima County MU's Glendale-29 & 30;
SSA-703 Tohono O'odham area MU's Glendale-28 & Grabe-31.Table 4. Representative soil features
Surface texture (1) Fine sandy loam
(2) Loam
(3) Silt loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate to moderately slow Soil depth 60 in Surface fragment cover <=3" 0 – 10 % Surface fragment cover >3" 0 – 1 % Available water capacity
(0-40in)5.8 – 10.8 in Calcium carbonate equivalent
(0-40in)0 – 10 % Electrical conductivity
(0-40in)0 – 4 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 13 Soil reaction (1:1 water)
(0-40in)7 – 8.2 Subsurface fragment volume <=3"
(Depth not specified)0 – 5 % 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 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 model, Loamy swale 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 1
Historical Climax Plant CommunityCommunity 1.1
Historical Climax Plant CommunityThe potential plant community on this site was a mixture of desert trees and shrubs with a midgrass understory. The aspect is savannah.
With continuous heavy grazing, perennial midrasses are removed from the plant community. When the grass cover is depleted the site is extemely susceptible to gully erosion. Mesquite, whitethorn acacia and creosotebush can increase quickly to dominate the plant community with heavy use and erosion. Base level changes in large watersheds can lead to eventual gullying of the site. With severe erosion the effectiveness of flooding is greatly reduced as is the site's ability to produce vegetation.
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 224 1000 1550 Forb 11 200 470 Tree 100 200 300 Shrub/Vine 11 110 220 Total 346 1510 2540 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% Biological crusts 10-30% Litter 30-70% Surface fragments >0.25" and <=3" 0-10% Surface fragments >3" 0-0% Bedrock 0% Water 0% Bare ground 10-50% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – – 1-5% 0-5% >0.5 <= 1 – – 5-25% 1-5% >1 <= 2 – 0-1% 15-25% 0-15% >2 <= 4.5 – 1-5% 1-20% 0-15% >4.5 <= 13 1-5% 0-10% 0-5% – >13 <= 40 1-15% – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 6. Plant community growth curve (percent production by month). AZ4012 , 40.1 10-13" p.z. bottom sites. Growth begins in the late winter, most growth occurs in the summer..
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 2 8 10 10 10 15 20 15 5 5 0 State 2
Annuals and desert broomCommunity 2.1
Annuals and desert broomThis state occurs after clearing for irrigation and subsequent abandonment. Early stages of plant succession lead to dominance by annual forbs and grasses (both native and non-native). Tumbleweed (Russian thistle) will persist with continued disturbance like disking. Desert broom can invade and may dominate the upper layer of the plant community. This state will persist for several years before other shrubs and desert trees come in and assume dominance. It will persist for long periods of time with continued disturbance. Natural flooding is reduced or eliminated by dikes, ditches and levees that were built to protect irrigated fields.
State 3
Mesquite, grass and shrubsCommunity 3.1
Mesquite, grass and shrubsThis state will result from long term rest of areas that were cleared and then abandoned. Without disturbance for 30 or 40 years mesquite will come in with other shrubs like saltbush and whitethorn acacia and form an open overstory. Perennial grasses, both native and non-native will dominate the understory especially in areas where water accumulates; the bottom ends of fields, furrows or borders. Annual forbs and grasses (both native and exotic) will fluctuate with climate. This appears to be a stable community without fire or other disturbance like continuous grazing. Usually water control features (dikes, ditches) are left intact and natural flooding of these areas does not occur.
State 4
Exotic perennial grasses with mesquiteCommunity 4.1
Exotic perennial grasses with mesquiteThis state occurs where non-native perennial grasses like bermuda, blue panic, Johnson grass, lovegrass and bufflegrass have been introduced or actually seeded on the site. These species dominate the under-story with mesquite in the over-story. In some areas these species were seeded on abandoned farmland to control weeds and erosion and persist with scattered mesquite.
State 5
Dense mesquiteCommunity 5.1
Dense mesquiteThis state occurs where mesquite has increased in the presence of continuous grazing. Mesquite forms an impenetrable thicket and is shrubby in stature. This can also occur on abandoned farmland where large floods have broken through the old dikes and deposited mesquite seed, organic debris and soil across large areas. The resulting stands of mesquite can be extremely dense.
State 6
ErodedCommunity 6.1
ErodedThis state occurs where the site has been gullied. Runoff water from adjacent uplands no longer contributes to flooding of the site and is quickly drained off by deep gullies. Base level changes in large stream systems can contribute to gully formation in areas of this site which are tributary. Loss of herbaceous cover and soil compaction and trailing caused by livestock and roads can lead to gully formation on the site.
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 Mid Grasses 100–400 whiplash pappusgrass PAVA2 Pappophorum vaginatum 25–300 – Arizona cottontop DICA8 Digitaria californica 0–100 – bush muhly MUPO2 Muhlenbergia porteri 25–100 – plains bristlegrass SEVU2 Setaria vulpiseta 0–50 – spike dropseed SPCO4 Sporobolus contractus 0–50 – 2 Dominant sod grass 100–400 vine mesquite PAOB Panicum obtusum 100–400 – 3 Misc perennial grasses 1–100 purple threeawn ARPU9 Aristida purpurea 0–25 – Parish's threeawn ARPUP5 Aristida purpurea var. parishii 0–25 – spidergrass ARTE3 Aristida ternipes 1–25 – spidergrass ARTEG Aristida ternipes var. gentilis 0–20 – cane bluestem BOBA3 Bothriochloa barbinodis 0–20 – sideoats grama BOCU Bouteloua curtipendula 0–20 – tobosagrass PLMU3 Pleuraphis mutica 0–20 – false Rhodes grass TRCR9 Trichloris crinita 0–20 – slim tridens TRMU Tridens muticus 0–5 – big galleta PLRI3 Pleuraphis rigida 0–5 – large-spike bristlegrass SEMA5 Setaria macrostachya 0–5 – sand dropseed SPCR Sporobolus cryptandrus 0–5 – black grama BOER4 Bouteloua eriopoda 0–5 – tanglehead HECO10 Heteropogon contortus 0–5 – Santa Rita threeawn ARCAG Aristida californica var. glabrata 0–5 – Indian ricegrass ACHY Achnatherum hymenoides 0–3 – giant dropseed SPGI Sporobolus giganteus 0–3 – low woollygrass DAPU7 Dasyochloa pulchella 0–2 – squirreltail ELELE Elymus elymoides ssp. elymoides 0–1 – mesa dropseed SPFL2 Sporobolus flexuosus 0–1 – 4 Tall grass 1–250 big sacaton SPWR2 Sporobolus wrightii 1–250 – 5 Annual grasses 22–400 Rothrock's grama BORO2 Bouteloua rothrockii 20–200 – feather fingergrass CHVI4 Chloris virgata 1–100 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 0–100 – Mexican panicgrass PAHI5 Panicum hirticaule 0–100 – sixweeks fescue VUOC Vulpia octoflora 0–50 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 0–50 – sticky sprangletop LEVI5 Leptochloa viscida 0–50 – canyon cupgrass ERLE7 Eriochloa lemmonii 0–50 – Arizona brome BRAR4 Bromus arizonicus 0–50 – prairie threeawn AROL Aristida oligantha 1–50 – Bigelow's bluegrass POBI Poa bigelovii 0–30 – needle grama BOAR Bouteloua aristidoides 0–25 – sixweeks grama BOBA2 Bouteloua barbata 0–25 – Parry's grama BOPA2 Bouteloua parryi 0–25 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 0–25 – tufted lovegrass ERPEP2 Eragrostis pectinacea var. pectinacea 0–25 – bearded cupgrass ERAR5 Eriochloa aristata 0–25 – sixweeks threeawn ARAD Aristida adscensionis 0–25 – Arizona signalgrass URAR Urochloa arizonica 0–20 – delicate muhly MUFR Muhlenbergia fragilis 0–5 – littleseed muhly MUMI Muhlenbergia microsperma 0–5 – witchgrass PACA6 Panicum capillare 0–5 – Eastwood fescue VUMIC Vulpia microstachys var. ciliata 0–2 – bristlegrass SETAR Setaria 0–2 – Forb6 Parasites 1–20 mesquite mistletoe PHCA8 Phoradendron californicum 1–20 – bigseed alfalfa dodder CUIN Cuscuta indecora 0–5 – 7 Perennial forbs 5–50 violet wild petunia RUNU Ruellia nudiflora 1–20 – desert globemallow SPAM2 Sphaeralcea ambigua 0–20 – spear globemallow SPHA Sphaeralcea hastulata 0–10 – spreading fleabane ERDI4 Erigeron divergens 0–10 – Indian rushpea HOGL2 Hoffmannseggia glauca 1–10 – fingerleaf gourd CUDI Cucurbita digitata 0–5 – coyote gourd CUPA Cucurbita palmata 0–5 – scarlet spiderling BOCO Boerhavia coccinea 0–5 – climbing wartclub BOSC Boerhavia scandens 0–5 – dwarf desertpeony ACNA2 Acourtia nana 0–5 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 0–5 – red-gland spurge CHME5 Chamaesyce melanadenia 0–2 – desert marigold BAMU Baileya multiradiata 0–2 – Missouri gourd CUFO Cucurbita foetidissima 0–2 – slender janusia JAGR Janusia gracilis 0–2 – wishbone-bush MILAV Mirabilis laevis var. villosa 0–2 – desert tobacco NIOBO Nicotiana obtusifolia var. obtusifolia 0–2 – spreading fanpetals SIAB Sida abutifolia 0–2 – New Mexico fanpetals SINE Sida neomexicana 0–2 – silverleaf nightshade SOEL Solanum elaeagnifolium 0–2 – Coulter's wrinklefruit TECO Tetraclea coulteri 0–2 – Louisiana vetch VILUL2 Vicia ludoviciana ssp. ludoviciana 0–2 – canaigre dock RUHY Rumex hymenosepalus 0–2 – Tumamoc globeberry TUMA Tumamoca macdougalii 0–1 – orange fameflower PHAU13 Phemeranthus aurantiacus 0–1 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 0–1 – spearleaf MAPA9 Matelea parvifolia 0–1 – lacy tansyaster MAPIP4 Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida 0–1 – bluedicks DICA14 Dichelostemma capitatum 0–1 – Watson's dutchman's pipe ARWA Aristolochia watsonii 0–1 – brownfoot ACWR5 Acourtia wrightii 0–1 – 8 Annual forbs 5–400 carelessweed AMPA Amaranthus palmeri 1–250 – wheelscale saltbush ATEL Atriplex elegans 0–100 – Nuttall's povertyweed MONU Monolepis nuttalliana 0–100 – Arizona popcornflower PLAR Plagiobothrys arizonicus 0–50 – bristly fiddleneck AMTE3 Amsinckia tessellata 0–50 – pitseed goosefoot CHBE4 Chenopodium berlandieri 0–50 – western tansymustard DEPI Descurainia pinnata 1–50 – Gordon's bladderpod LEGO Lesquerella gordonii 0–25 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–20 – smallflowered milkvetch ASNU4 Astragalus nuttallianus 0–20 – Coulter's globemallow SPCO2 Sphaeralcea coulteri 0–20 – thelypody THELY Thelypodium 0–15 – ivyleaf morning-glory IPHE Ipomoea hederacea 0–15 – tripleleaf morning-glory IPTE5 Ipomoea ternifolia 0–15 – Arizona poppy KAGR Kallstroemia grandiflora 0–10 – biannual lettuce LALU Lactuca ludoviciana 0–10 – mesa tansyaster MATA Machaeranthera tagetina 0–10 – tanseyleaf tansyaster MATA2 Machaeranthera tanacetifolia 0–10 – hyssopleaf sandmat CHHY3 Chamaesyce hyssopifolia 0–10 – yellow tackstem CAPA7 Calycoseris parryi 0–10 – white tackstem CAWR Calycoseris wrightii 0–10 – Coulter's spiderling BOCO2 Boerhavia coulteri 0–10 – fringed amaranth AMFI Amaranthus fimbriatus 0–10 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–10 – New Mexico plumeseed RANE Rafinesquia neomexicana 0–10 – Lemmon's ragwort SELE8 Senecio lemmonii 0–10 – desert Indianwheat PLOV Plantago ovata 0–10 – woolly plantain PLPA2 Plantago patagonica 0–10 – purslane PORTU Portulaca 0–10 – manybristle chinchweed PEPA2 Pectis papposa 0–10 – Arizona phacelia PHAR13 Phacelia arizonica 0–10 – cleftleaf wildheliotrope PHCR Phacelia crenulata 0–10 – coastal bird's-foot trefoil LOSAB Lotus salsuginosus var. brevivexillus 0–10 – bean PHASE Phaseolus 2–9 – distant phacelia PHDI Phacelia distans 0–5 – slimjim bean PHFI3 Phaseolus filiformis 0–5 – doubleclaw PRPA2 Proboscidea parviflora 0–5 – California desertdandelion MACA6 Malacothrix californica 0–5 – sleepy silene SIAN2 Silene antirrhina 0–5 – Louisiana vetch VILUL2 Vicia ludoviciana ssp. ludoviciana 0–5 – hoary bowlesia BOIN3 Bowlesia incana 0–5 – cryptantha CRYPT Cryptantha 0–5 – Sonoran sandmat CHMI7 Chamaesyce micromera 0–5 – fringed redmaids CACI2 Calandrinia ciliata 0–5 – whitestem blazingstar MEAL6 Mentzelia albicaulis 0–5 – American wild carrot DAPU3 Daucus pusillus 0–5 – star gilia GIST Gilia stellata 0–5 – crestrib morning-glory IPCO2 Ipomoea costellata 0–5 – redstar IPCO3 Ipomoea coccinea 0–5 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–2 – California goldfields LACAC2 Lasthenia californica ssp. californica 0–2 – New Mexico thistle CINE Cirsium neomexicanum 0–2 – desert thorn-apple DADI2 Datura discolor 0–2 – pricklyburr DAIN2 Datura inoxia 0–2 – miniature woollystar ERDI2 Eriastrum diffusum 0–2 – buckwheat ERIOG Eriogonum 0–2 – California suncup CACA32 Camissonia californica 0–2 – woollyhead neststraw STMI2 Stylocline micropoides 0–2 – sand fringepod THCU Thysanocarpus curvipes 0–2 – hedgemustard SISYM Sisymbrium 0–2 – green carpetweed MOVE Mollugo verticillata 0–2 – desert evening primrose OEPR Oenothera primiveris 0–2 – Florida pellitory PAFL3 Parietaria floridana 0–2 – pellitory PARIE Parietaria 0–2 – combseed PECTO Pectocarya 0–2 – Mexican passionflower PAME2 Passiflora mexicana 0–1 – bristly nama NAHI Nama hispidum 0–1 – slender goldenweed MAGR10 Machaeranthera gracilis 0–1 – London rocket SIIR Sisymbrium irio 0–1 – Texas stork's bill ERTE13 Erodium texanum 0–1 – Palmer's spectaclepod DICA31 Dimorphocarpa candicans 0–1 – wedgeleaf draba DRCU Draba cuneifolia 0–1 – Mexican fireplant EUHE4 Euphorbia heterophylla 0–1 – Arizona cottonrose LOAR12 Logfia arizonica 0–1 – Lindley's silverpuffs MILI5 Microseris lindleyi 0–1 – Shrub/Vine9 Large shrubs 10–150 whitethorn acacia ACCO2 Acacia constricta 2–100 – creosote bush LATRT Larrea tridentata var. tridentata 1–50 – fourwing saltbush ATCA2 Atriplex canescens 1–25 – Arizona desert-thorn LYEX Lycium exsertum 0–15 – cattle saltbush ATPO Atriplex polycarpa 0–10 – spiny hackberry CEEH Celtis ehrenbergiana 0–10 – crucifixion thorn CAEM4 Castela emoryi 0–5 – soaptree yucca YUEL Yucca elata 0–5 – lotebush ZIOB Ziziphus obtusifolia 0–5 – Berlandier's wolfberry LYBE Lycium berlandieri 0–5 – desertbroom BASA2 Baccharis sarothroides 0–2 – desert willow CHLI2 Chilopsis linearis 0–2 – Nevada jointfir EPNE Ephedra nevadensis 0–2 – ambrosia leaf bur ragweed AMAM2 Ambrosia ambrosioides 0–2 – Thurber's desert honeysuckle ANTH2 Anisacanthus thurberi 0–1 – longleaf jointfir EPTR Ephedra trifurca 0–1 – 10 Dominant vines 1–40 Drummond's clematis CLDR Clematis drummondii 0–20 – fringed twinevine FUCYC Funastrum cynanchoides ssp. cynanchoides 0–10 – Gila manroot MAGI Marah gilensis 0–10 – yellowhood NISSO Nissolia 0–5 – fetid passionflower PAFO2 Passiflora foetida 0–5 – climbing arrowheads SIGR Sicyosperma gracile 0–5 – 11 Succulents 0–20 cactus apple OPEN3 Opuntia engelmannii 0–10 – tulip pricklypear OPPH Opuntia phaeacantha 0–5 – Arizona pencil cholla CYAR14 Cylindropuntia arbuscula 0–5 – Christmas cactus CYLE8 Cylindropuntia leptocaulis 0–5 – staghorn cholla CYVE3 Cylindropuntia versicolor 0–2 – dollarjoint pricklypear OPCH Opuntia chlorotica 0–2 – nightblooming cereus PEGRG Peniocereus greggii var. greggii 0–1 – candy barrelcactus FEWI Ferocactus wislizeni 0–1 – devil's cholla GRKU Grusonia kunzei 0–1 – walkingstick cactus CYSP8 Cylindropuntia spinosior 0–1 – jumping cholla CYFU10 Cylindropuntia fulgida 0–1 – buck-horn cholla CYAC8 Cylindropuntia acanthocarpa 0–1 – 12 Half shrubs 0–10 fairyduster CAER Calliandra eriophylla 0–5 – snakewood CONDA Condalia 0–2 – alkali goldenbush ISACA2 Isocoma acradenia var. acradenia 0–2 – burroweed ISTE2 Isocoma tenuisecta 0–2 – littleleaf ratany KRER Krameria erecta 0–2 – white ratany KRGR Krameria grayi 0–2 – woolly fruit bur ragweed AMER Ambrosia eriocentra 0–2 – rubber rabbitbrush ERNAG Ericameria nauseosa ssp. nauseosa var. glabrata 0–2 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–1 – shortleaf baccharis BABR Baccharis brachyphylla 0–1 – Coulter's brickellbush BRCO Brickellia coulteri 0–1 – whitestem paperflower PSCO2 Psilostrophe cooperi 0–1 – Mexican bladdersage SAME Salazaria mexicana 0–1 – American threefold TRCA8 Trixis californica 0–1 – toothleaf goldeneye VIDE3 Viguiera dentata 0–1 – brittlebush ENFA Encelia farinosa 0–1 – buckwheat ERIOG Eriogonum 0–1 – rayless goldenhead ACSP Acamptopappus sphaerocephalus 0–1 – triangle bur ragweed AMDE4 Ambrosia deltoidea 0–1 – Tree13 Trees 100–300 velvet mesquite PRVE Prosopis velutina 100–300 – catclaw acacia ACGR Acacia greggii 0–50 – Jerusalem thorn PAAC3 Parkinsonia aculeata 0–20 – blue paloverde PAFL6 Parkinsonia florida 0–20 – yellow paloverde PAMI5 Parkinsonia microphylla 0–20 – desert ironwood OLTE Olneya tesota 0–10 – 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 (%) Interpretations
Animal community
The plant community on this site is suitable for grazing by all classes of cattle. Because of water availability in the rainy seasons,long green seasons, shade and easy accessibility, this site is often overused. Large areas should be fenced and managed separately from adjacent upland sites. Grazing should be avoided during the summer flood season to avoid damage by trampling the muddy soils and because heat, humidity and insects reduce livestock performance. The plant community provides adequate nutrition for livestock throughout the year.
Free water is available in the summer rainy season in natural charcos and discontinuous gullies. Forage diversity, shade and cover are very good and make this site home to a great variety of wildlife species including the larger desert mammals. Water developments which prolong the availability of free water are very important to the larger wildlife species on the site.Hydrological functions
Medium to heavy textured soils and flat slopes make this site a fair producer of runoff. The site recieves extra water in the form of runin from adjacent uplands and watershed areas.
Recreational uses
Hunting, camping, hiking, birdwatching, photography, horseback riding.
Wood products
Good supplies of mesquite for firewood.
Other products
Mesquite beans and cactus fruits
Supporting information
Inventory data references
Range 417s include 4 in good condition.
Type locality
Location 1: Pima County, AZ Township/Range/Section T16S R15E S14 General legal description Tucson FO - Pima County Fairgrounds Location 2: Pima County, AZ Township/Range/Section T20S R5E S23 General legal description Sells FO - Chutum Vaya Assoc. Community Pastures Location 3: Pima County, AZ Township/Range/Section T14S R11E S31 General legal description La Tortuga Ranch, In Conservation Ditch Pasture at KA 1. Ungrazed 7 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, Emilio Carrillo Contact for lead author NRCS Tucson Area Office Date 03/08/2005 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
Rills are present on this site but are well vegetated and not eroding. -
Presence of water flow patterns:
Uncommon; probably cover no more than 5% of area; very short and discontinuous, 1-2 terracetes. -
Number and height of erosional pedestals or terracettes:
Slope is 0-1% and not onducive to forming pedestals and terracettes. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-15% -
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):
All litter size classes staying in place, occasionally transported in flow paths. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Expect values of 5-6 across site. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
WEak thin platy to weak granular to moderate subangular block; color is 7.5-10YR6/4 dry, .5-10YR4/4 moist; thickness to 4 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Canopy 60-70%; asa 15-25%, litter 15%: 80% canopy covery is perennial grasses, 2-5% forbs, 15% shrubs and trees. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None -
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
perennial mid grasses > trees & shrubs > short grasses > grasslike species > perennial forbs > annual grasses and forbs.Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
50% basal area lost on perennial grasses. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
346 lbs/ac unfavorable precipitation, 1510 lbs/ac normal precipitation, 2540 lbs/ac 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, whitethorn, creosote, Bermuda grass, Johnson grass, blue panic, bufflegrass, yellow bluestem, London Rocket, malta starthistle, cheeseweed, cocklebur -
Perennial plant reproductive capability:
Nt affected even following several years of prolonged drought period for region.
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PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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