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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.Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
This site occurs on hillslopes and ridgetops. Slope aspect is site differentiating at elevations near land resource area boundaries.
Table 2. Representative physiographic features
Landforms (1) Hill
(2) Ridge
Flooding frequency None Ponding frequency None Elevation 3800 – 5500 ft Slope 15 – 70 % 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 durarion and low density. 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 nutritions 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
Soil features
These are shallow soils formed in slope alluvium of mixed basic igneous and cargonatic minerology. Soils are calcareous loams and clay loams with a complete cover of basalt cobbles and stones. Large areas of talus or rock slides occur intermingled with soil areas. Plant-soil moisture relationships are fair.
Soils mapped on this site include: SSA-664 San Simon area MU's 5 & 25 Graham; SSA-669 Pima county Eastern part MU 32 Graham; SSA-671 Cochise county Douglas-Tombstone part MU's 16 Boss, Krentz & Paramore, 75 Graham & Lampshire.Table 4. Representative soil features
Parent material (1) Slope alluvium – basalt
Surface texture (1) Loam
(2) Clay loam
Permeability class Moderate 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 ben 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
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Click on state and transition labels to scroll to the respective textEcosystem states
State 1 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. Shrubs are well represented on the site, as well as perennial and annual forbs. The major grass species tend to be well dispersed througout the plant community. Shrubs are concentrated at the edge of outcrops and along talus slides. The aspect is dotted grassland.
Figure 4. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Grass/Grasslike 540 – 630 Shrub/Vine 180 – 270 Forb 90 – 135 Total 810 – 1035 Figure 5. Plant community growth curve (percent production by month). AZ4131 , 41.3 12-16" p.z. hill sites. Growth begins in the spring, semi-dormancy occurs during the June drought, most growth occurs during the summer rainy season..
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 10 0 30 30 10 5 0 0 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 180–270 black grama BOER4 Bouteloua eriopoda 180–270 – 2 135–225 sideoats grama BOCU Bouteloua curtipendula 135–225 – 3 270 cane bluestem BOBA3 Bothriochloa barbinodis 270 – Arizona cottontop DICA8 Digitaria californica 270 – bush muhly MUPO2 Muhlenbergia porteri 270 – 4 45–90 Orcutt's threeawn ARSCO Aristida schiedeana var. orcuttiana 45–90 – spidergrass ARTE3 Aristida ternipes 45–90 – spidergrass ARTEG Aristida ternipes var. gentilis 45–90 – plains lovegrass ERIN Eragrostis intermedia 45–90 – tanglehead HECO10 Heteropogon contortus 45–90 – green sprangletop LEDU Leptochloa dubia 45–90 – tobosagrass PLMU3 Pleuraphis mutica 45–90 – plains bristlegrass SEVU2 Setaria vulpiseta 45–90 – spike dropseed SPCO4 Sporobolus contractus 45–90 – sand dropseed SPCR Sporobolus cryptandrus 45–90 – 5 9–45 sixweeks threeawn ARAD Aristida adscensionis 9–45 – needle grama BOAR Bouteloua aristidoides 9–45 – sixweeks grama BOBA2 Bouteloua barbata 9–45 – Arizona brome BRAR4 Bromus arizonicus 9–45 – feather fingergrass CHVI4 Chloris virgata 9–45 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 9–45 – little barley HOPU Hordeum pusillum 9–45 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 9–45 – mucronate sprangletop LEPA6 Leptochloa panicea 9–45 – Arizona signalgrass URAR Urochloa arizonica 9–45 – sixweeks fescue VUOC Vulpia octoflora 9–45 – 6 9–45 low woollygrass DAPU7 Dasyochloa pulchella 9–45 – nineawn pappusgrass ENDE Enneapogon desvauxii 9–45 – Palmer's crinklemat TIPA Tiquilia palmeri 9–45 – slim tridens TRMU Tridens muticus 9–45 – 7 9–45 sprucetop grama BOCH Bouteloua chondrosioides 9–45 – blue grama BOGR2 Bouteloua gracilis 9–45 – hairy grama BOHI2 Bouteloua hirsuta 9–45 – purple grama BORA Bouteloua radicosa 9–45 – slender grama BORE2 Bouteloua repens 9–45 – curly-mesquite HIBE Hilaria belangeri 9–45 – common wolfstail LYPH Lycurus phleoides 9–45 – Hall's panicgrass PAHA Panicum hallii 9–45 – vine mesquite PAOB Panicum obtusum 9–45 – 8 9–45 poverty threeawn ARDI5 Aristida divaricata 9–45 – Havard's threeawn ARHA3 Aristida havardii 9–45 – Wooton's threeawn ARPA9 Aristida pansa 9–45 – purple threeawn ARPU9 Aristida purpurea 9–45 – blue threeawn ARPUN Aristida purpurea var. nealleyi 9–45 – sedge CAREX Carex 9–45 – squirreltail ELELE Elymus elymoides ssp. elymoides 9–45 – bullgrass MUEM Muhlenbergia emersleyi 9–45 – creeping muhly MURE Muhlenbergia repens 9–45 – slender muhly MUTE4 Muhlenbergia tenuifolia 9–45 – Texas bluestem SCCI2 Schizachyrium cirratum 9–45 – slim tridens TRMUE Tridens muticus var. elongatus 9–45 – Forb9 45–90 dwarf Indian mallow ABPA3 Abutilon parvulum 45–90 – San Felipe dogweed ADPO Adenophyllum porophylloides 45–90 – trailing windmills ALIN Allionia incarnata 45–90 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 45–90 – anoda ANODA Anoda 45–90 – desert marigold BAMU Baileya multiradiata 45–90 – spreading fleabane ERDI4 Erigeron divergens 45–90 – Arizona snakecotton FRAR2 Froelichia arizonica 45–90 – haplopappus HAPLO11 Haplopappus 45–90 – slender janusia JAGR Janusia gracilis 45–90 – tree tobacco NIGL Nicotiana glauca 45–90 – Wright's cudweed PSCAC2 Pseudognaphalium canescens ssp. canescens 45–90 – twinleaf senna SEBA3 Senna bauhinioides 45–90 – spreading fanpetals SIAB Sida abutifolia 45–90 – desert globemallow SPAM2 Sphaeralcea ambigua 45–90 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 45–90 – 10 45 carelessweed AMPA Amaranthus palmeri 45 – pioneer rockcress ARPL Arabis platysperma 45 – clasping milkweed ASAM Asclepias amplexicaulis 45 – aster ASTER Aster 45 – milkvetch ASTRA Astragalus 45 – hairyseed bahia BAAB Bahia absinthifolia 45 – spiderling BOERH2 Boerhavia 45 – hoary bowlesia BOIN3 Bowlesia incana 45 – lipfern CHEIL Cheilanthes 45 – goosefoot CHENO Chenopodium 45 – fingerleaf gourd CUDI Cucurbita digitata 45 – American wild carrot DAPU3 Daucus pusillus 45 – western tansymustard DEPI Descurainia pinnata 45 – fetid marigold DYPA Dyssodia papposa 45 – flatcrown buckwheat ERDE6 Eriogonum deflexum 45 – spurge EUPHO Euphorbia 45 – Indian rushpea HOGL2 Hoffmannseggia glauca 45 – redstar IPCO3 Ipomoea coccinea 45 – ragged nettlespurge JAMA Jatropha macrorhiza 45 – prickly lettuce LASE Lactuca serriola 45 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 45 – intermediate pepperweed LEVIM Lepidium virginicum var. medium 45 – common deerweed LOSC2 Lotus scoparius 45 – blazingstar MENTZ Mentzelia 45 – minerslettuce MONTI Montia 45 – cloak fern NOTHO Notholaena 45 – owl's-clover ORTHO Orthocarpus 45 – Florida pellitory PAFL3 Parietaria floridana 45 – chinchweed PECTI Pectis 45 – cliffbrake PELLA Pellaea 45 – Parry's beardtongue PEPA24 Penstemon parryi 45 – Nine Mile Canyon phacelia PHNO Phacelia novenmillensis 45 – desert Indianwheat PLOV Plantago ovata 45 – silverleaf nightshade SOEL Solanum elaeagnifolium 45 – pricklyleaf dogweed THAC Thymophylla acerosa 45 – rue of the mountains THTE2 Thamnosma texana 45 – woolly tidestromia TILA2 Tidestromia lanuginosa 45 – catnip noseburn TRNE Tragia nepetifolia 45 – verbena VEPO4 Verbena polystachya 45 – American vetch VIAM Vicia americana 45 – garden vetch VISAN2 Vicia sativa ssp. nigra 45 – Shrub/Vine11 45–90 whitethorn acacia ACCO2 Acacia constricta 45–90 – Wright's beebrush ALWR Aloysia wrightii 45–90 – Palmer's cock's comb CEPA5 Celosia palmeri 45–90 – creosote bush LATRT Larrea tridentata var. tridentata 45–90 – 12 45–90 pelotazo ABIN Abutilon incanum 45–90 – fourwing saltbush ATCA2 Atriplex canescens 45–90 – yerba de pasmo BAPT Baccharis pteronioides 45–90 – resinleaf brickellbush BRBA2 Brickellia baccharidea 45–90 – fairyduster CAER Calliandra eriophylla 45–90 – Cooley's bundleflower DECO2 Desmanthus cooleyi 45–90 – ookow DICO19 Dichelostemma congestum 45–90 – longleaf jointfir EPTR Ephedra trifurca 45–90 – bastardsage ERWR Eriogonum wrightii 45–90 – rock sage SAPI2 Salvia pinguifolia 45–90 – American threefold TRCA8 Trixis californica 45–90 – desert zinnia ZIAC Zinnia acerosa 45–90 – 13 9–45 pelotazo ABIN Abutilon incanum 9–45 – prairie acacia ACAN Acacia angustissima 9–45 – catclaw acacia ACGR Acacia greggii 9–45 – milfoil wattle ACMI Acacia millefolia 9–45 – netleaf hackberry CELAR Celtis laevigata var. reticulata 9–45 – oneseed juniper JUMO Juniperus monosperma 9–45 – desert-thorn LYCIU Lycium 9–45 – mariola PAIN2 Parthenium incanum 9–45 – honey mesquite PRGLG Prosopis glandulosa var. glandulosa 9–45 – littleleaf sumac RHMI3 Rhus microphylla 9–45 – Wright's mock buckthorn SAWR Sageretia wrightii 9–45 – woody crinklemat TICAC Tiquilia canescens var. canescens 9–45 – lotebush ZIOB Ziziphus obtusifolia 9–45 – 14 9–18 desertbroom BASA2 Baccharis sarothroides 9–18 – threadleaf snakeweed GUMI Gutierrezia microcephala 9–18 – broom snakeweed GUSA2 Gutierrezia sarothrae 9–18 – burroweed ISTE2 Isocoma tenuisecta 9–18 – alyssumleaf phlox PHALA4 Phlox alyssifolia ssp. abdita 9–18 – Douglas' spikemoss SEDO Selaginella douglasii 9–18 – 15 9–45 desert agave AGDE Agave deserti 9–45 – Bill Williams Mountain giant hyssop AGPA Agastache pallidiflora 9–45 – common sotol DAWH2 Dasylirion wheeleri 9–45 – candy barrelcactus FEWI Ferocactus wislizeni 9–45 – ocotillo FOSP2 Fouquieria splendens 9–45 – globe cactus MAMMI Mammillaria 9–45 – sacahuista NOMI Nolina microcarpa 9–45 – beavertail pricklypear OPBA2 Opuntia basilaris 9–45 – limestone adderstongue OPEN Ophioglossum engelmannii 9–45 – banana yucca YUBA Yucca baccata 9–45 – Schott's yucca YUSC Yucca ×schottii 9–45 – Interpretations
Animal community
This site produces fair quality herbaceous forage. High soil pH is somewhat offset by inherent soil fertility. The site is not well suited to summertime grazing by cows with calves. Mother cow pairs will only use 300-400 feet, up or down in elevation, from water in the summer. Dry cows will use double that distance in the cool season. Yearling cattle make good use of the site in any season. Slope aspect affects both the intensity of use and seasonal use patterns. North-south trending slopes will be used fairly well even in summer, as the wets slope is shady in the morning and the east slope is shady in the afternoon. South facing slopes are used heavily in the winter-spring due to warmth from cold weather and early greenup of warm season grasses. North facing slopes, bieng shady and cooler, are used in the summer, and especially in the fall as the perennial grasses stay greener longer into the cool season. Very dar colored rock and soil surfaces cause early soil warming and, consequently, earlier greenup of warm season perennial grasses in the spring. Seep and canyon water is available in most winters from December-February.
Water developments are very important to wildlife on this site. The site is home to a wide variety of wildlife species due to the diversity of food, cover and edge.Supporting information
Type locality
Location 1: Cochise County, AZ Township/Range/Section T23S R29E S29 General legal description Rocker M Ranch Location 2: Pima County, AZ Township/Range/Section T18S R10E S28 General legal description Batamote Ranch Location 3: Cochise County, AZ Township/Range/Section T20S R24E S7 General legal description Cowan Ranch Contributors
Dan Robinett
Larry D. Ellicott
Steve Barker
Unknown
UnknwonRangeland 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 USDA-NRCS Tucson Area Office Date 02/25/2005 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
None present on this site. -
Presence of water flow patterns:
Uncommon; probably cover no more than 10% of area; discontinuous; very short, usually less than 1 foot in length; broken primarily by high rock and gravel cover. -
Number and height of erosional pedestals or terracettes:
Pedestals are uncommon on perennial grass and shrubs; Limited soil material not conducive to forming continuous stands of plants that promote terracettes; high rock cover forms limited natural terracettes. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Estimated at 0-5%. -
Number of gullies and erosion associated with gullies:
None present on this site. -
Extent of wind scoured, blowouts and/or depositional areas:
None present on this site. -
Amount of litter movement (describe size and distance expected to travel):
All litter size classes staying in place. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
No slake test done. Expect values of 1-2 in canopy interspaces, and 4 - 6 under plant canopies. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Weak coarse granular; Color is 10YR5/4 Dry, 10YR3/2 Moist; thickness to 3 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Cover estimated as: Canopy 20-30%, Basal 5%, Litter 45-55%, and Gravel 30%; 10% of canopy cover is perennial mid grasses, 25% short grasses, 5% perennial forbs, 45% shrubs and 10% subshrubs. Cover is well dispersed throughout site. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None present on this site. -
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 grass = shrubsSub-dominant:
annual grasses & forbs > subshrubs > succulents = perennial forbsOther:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
2-3% of perennial grass plants have died with skeletons still present; 50% of basal cover of perennial grasses has been 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):
600 lbs/acre unfavorable precipitation, 900 lbs/acre normal precipitation, 1,300 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:
turpentine bush, jojoba, whitethorn, mesquite, prickly pear, cane cholla, ocotillo may increase to undesirable levels in the absence of natural fires; Red brome and wild oats. -
Perennial plant reproductive capability:
Not affected even following several years of prolonged drought period for region.
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