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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 40.2 – Middle Sonoran Desert
Elevations range from 1200 to 2000 feet and precipitation averages 7 to 10 inches per year. Vegetation includes saguaro, palo verde, creosotebush, triangle bursage, brittlebush, prickly pear, cholla, desert saltbush, wolfberry bush muhly, threeawns, and big galleta. The soil temperature regime is hyperthermic 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.Table 1. Dominant plant species
Tree (1) Parkinsonia florida
Shrub (1) Ambrosia deltoidea
(2) Eriogonum fasciculatumHerbaceous (1) Pleuraphis rigida
(2) Tridens muticus var. elongatusPhysiographic features
This site occurs as steep hills, schist hillslopes and mountain slopes. Rock outcrop consists of vertically oriented, fractured schist and can make up 15-20% of the area. Outcrops are usually the ridge and mountain tops.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Flooding duration Very brief (4 to 48 hours) Flooding frequency None Ponding frequency None Elevation 1500 – 3500 ft Slope 15 – 70 % Aspect Aspect is not a significant factor Climatic features
Precipitation in the sub-resource area ranges from 7 to 10 inches. Elevations range from 900 to 2050 feet. Winter-summer rainfall ratios range from 40% to 60% in the southern part along the international boundary, to 60% to 40% in the central and northern parts of the sub-resource area. As one moves from east to west in this resource area rains become more unpredictable and variable with Coefficients of Variation of annual rainfall equal to 38% at Florence and 46% at Aguila. Summer rains fall July- September, originate in the Gulf of Mexico, and are convective, usually brief, intense thunderstorms. Summer precipitation is extremely erratic and undependable in this area. Cool season moisture tends to be frontal, originates in the Pacific and Gulf of California, and falls in widespread storms with long duration and low intensity. This is the dependable moisture supply for vegetation in the area. Snow is very rare and usually melts on contact. May-June is the driest time of the year. Humidity is very low.
Winter temperatures are very mild with very few days recording freezing for short periods of time. Summertime temperatures are hot to very hot with many days in June-July exceeding 105 degrees F. Frost-free days range from 280 at stations in major river valleys with cold air drainage to 320 to 350 days at upland stations.
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) 350 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
Soil features
These soils are very shallow to shallow. They are generally very gravelly loams and weakly calcareous with a cover of small rock fragments. Plant-soil relationships is generally fair.
Soils mapped on this site include: SSA-645 Aguila-Carefree area MU's Dixaleta-32 & Schenco-108 & 109; SSA-653 Laposa-58 and Schenco-58.Table 4. Representative soil features
Surface texture (1) Gravelly loam
(2) Channery loam
Family particle size (1) Loamy
Drainage class Well drained to somewhat excessively drained Permeability class Moderately slow to moderate Soil depth 5 – 20 in Surface fragment cover <=3" 35 – 80 % Available water capacity
(0-40in)0 – 2.5 in Electrical conductivity
(0-40in)0 – 4 mmhos/cm Sodium adsorption ratio
(0-40in)1 – 5 Soil reaction (1:1 water)
(0-40in)7.4 – 8.4 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 grazing, fire, 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 shown for the group. Divide the resulting total by the total normal year production shown in the plant community description. If 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
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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 native plant community on this site is a mixture of perennial grasses, desert shrubs and cacti. Annual grasses and forbs make up a fair portion of the plant community.
As the desireable perennial grasses decline on this site, undesireable species such as chollas, paperflower and bursage will increase.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)Shrub/Vine 225 259 293 Grass/Grasslike 113 146 180 Forb 45 56 68 Tree 23 34 45 Total 406 495 586 Figure 5. Plant community growth curve (percent production by month). AZ4021 , 40.2 7-10" p.z. upland sites. Plants remain green all year, most growth occurs in late winter to early spring..
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 5 10 15 30 15 0 5 5 5 0 5 5 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike0 Dominant Grasses 113–180 big galleta PLRI3 Pleuraphis rigida 45–68 – slim tridens TRMU Tridens muticus 23–45 – bush muhly MUPO2 Muhlenbergia porteri 5–23 – 1 Misc Perennial Grasses 5–23 threeawn ARIST Aristida 1–5 – tobosagrass PLMU3 Pleuraphis mutica 1–5 – large-spike bristlegrass SEMA5 Setaria macrostachya 1–5 – nineawn pappusgrass ENDE Enneapogon desvauxii 0–5 – tanglehead HECO10 Heteropogon contortus 0–4 – sand dropseed SPCR Sporobolus cryptandrus 0–4 – Arizona cottontop DICA8 Digitaria californica 0–4 – desert needlegrass ACSP12 Achnatherum speciosum 0–4 – red grama BOTR2 Bouteloua trifida 0–2 – 2 Annual Grasses 23–45 Hall's panicgrass PAHA Panicum hallii 1–5 – Bigelow's bluegrass POBI Poa bigelovii 1–5 – Arizona signalgrass URAR Urochloa arizonica 1–5 – Pacific fescue VUMIP Vulpia microstachys var. pauciflora 1–4 – sixweeks threeawn ARAD Aristida adscensionis 1–4 – needle grama BOAR Bouteloua aristidoides 1–4 – sixweeks grama BOBA2 Bouteloua barbata 1–4 – Rothrock's grama BORO2 Bouteloua rothrockii 1–4 – Arizona brome BRAR4 Bromus arizonicus 1–4 – low woollygrass DAPU7 Dasyochloa pulchella 1–4 – littleseed muhly MUMI Muhlenbergia microsperma 1–4 – Forb4 Perennial Forbs 23–45 desert globemallow SPAM2 Sphaeralcea ambigua 2–5 – New Mexico silverbush ARNE2 Argythamnia neomexicana 2–5 – wishbone-bush MILAV Mirabilis laevis var. villosa 2–5 – Louisiana vetch VILUL2 Vicia ludoviciana ssp. ludoviciana 2–5 – Mojave woodyaster XYTOT Xylorhiza tortifolia var. tortifolia 1–4 – desert Indianwheat PLOV Plantago ovata 1–4 – trailing windmills ALIN Allionia incarnata 2–4 – common fiddleneck AMMEI2 Amsinckia menziesii var. intermedia 1–4 – bristly fiddleneck AMTE3 Amsinckia tessellata 1–4 – milkvetch ASTRA Astragalus 2–4 – desert marigold BAMU Baileya multiradiata 1–4 – cryptantha CRYPT Cryptantha 1–4 – bluedicks DICAC5 Dichelostemma capitatum ssp. capitatum 1–4 – desert trumpet ERIN4 Eriogonum inflatum 1–4 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 1–4 – 5 Annual Forbs 0–23 aster ASTER Aster 0–1 – scarlet spiderling BOCO Boerhavia coccinea 0–1 – spiderling BOERH2 Boerhavia 0–1 – hoary bowlesia BOIN3 Bowlesia incana 0–1 – California suncup CACA32 Camissonia californica 0–1 – exserted Indian paintbrush CAEXE Castilleja exserta ssp. exserta 0–1 – mariposa lily CALOC Calochortus 0–1 – brittle spineflower CHBR Chorizanthe brevicornu 0–1 – devil's spineflower CHRI Chorizanthe rigida 0–1 – New Mexico thistle CINE Cirsium neomexicanum 0–1 – hairy prairie clover DAMO Dalea mollis 0–1 – American wild carrot DAPU3 Daucus pusillus 0–1 – larkspur DELPH Delphinium 0–1 – flatcrown buckwheat ERDE6 Eriogonum deflexum 0–1 – woollystar ERIAS Eriastrum 0–1 – fleabane ERIGE2 Erigeron 0–1 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–1 – spurge EUPHO Euphorbia 0–1 – gilia GILIA Gilia 0–1 – Gordon's bladderpod LEGO Lesquerella gordonii 0–1 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–1 – pepperweed LEPID Lepidium 0–1 – foothill deervetch LOHU2 Lotus humistratus 0–1 – strigose bird's-foot trefoil LOSTT Lotus strigosus var. tomentellus 0–1 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–1 – desertdandelion MALAC3 Malacothrix 0–1 – Parry's false prairie-clover MAPA7 Marina parryi 0–1 – blazingstar MENTZ Mentzelia 0–1 – glandular threadplant NEGL Nemacladus glanduliferus 0–1 – evening primrose OENOT Oenothera 0–1 – combseed PECTO Pectocarya 0–1 – Emory's rockdaisy PEEM Perityle emoryi 0–1 – beardtongue PENST Penstemon 0–1 – woolly plantain PLPA2 Plantago patagonica 0–1 – New Mexico plumeseed RANE Rafinesquia neomexicana 0–1 – chia SACO6 Salvia columbariae 0–1 – Coues' cassia SECO10 Senna covesii 0–1 – Lemmon's ragwort SELE8 Senecio lemmonii 0–1 – sleepy silene SIAN2 Silene antirrhina 0–1 – catchfly SILEN Silene 0–1 – blue-eyed grass SISYR Sisyrinchium 0–1 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–1 – Shrub/Vine6 Dominant Shrubs 85–135 triangle bur ragweed AMDE4 Ambrosia deltoidea 23–45 – brittlebush ENFA Encelia farinosa 23–40 – creosote bush LATRT Larrea tridentata var. tridentata 20–35 – desert ironwood OLTE Olneya tesota 15–30 – littleleaf ratany KRER Krameria erecta 15–30 – Eastern Mojave buckwheat ERFA2 Eriogonum fasciculatum 5–10 – ocotillo FOSP2 Fouquieria splendens 1–5 – 7 Mid Shrubs 45–70 burrobush AMDU2 Ambrosia dumosa 5–10 – Nevada jointfir EPNE Ephedra nevadensis 5–10 – longleaf jointfir EPTR Ephedra trifurca 5–10 – Mexican bladdersage SAME Salazaria mexicana 5–10 – jojoba SICH Simmondsia chinensis 5–10 – Coulter's brickellbush BRCO Brickellia coulteri 3–8 – narrowleaf silverbush ARLA12 Argythamnia lanceolata 3–5 – California fagonbush FALA Fagonia laevis 0–5 – southern goldenbush ISPL Isocoma pluriflora 0–5 – slender janusia JAGR Janusia gracilis 0–5 – desert-thorn LYCIU Lycium 3–5 – Goodding's tansyaster MAPIG2 Machaeranthera pinnatifida ssp. gooddingii var. gooddingii 3–5 – rough menodora MESC Menodora scabra 0–5 – slender poreleaf POGR5 Porophyllum gracile 0–5 – toothleaf goldeneye VIDE3 Viguiera dentata 3–5 – 8 Misc Shrubs 90–145 catclaw acacia ACGR Acacia greggii 10–25 – spearleaf brickellbush BRAT Brickellia atractyloides 10–25 – white ratany KRGR Krameria grayi 10–25 – whitestem paperflower PSCO2 Psilostrophe cooperi 10–25 – button brittlebush ENFR Encelia frutescens 10–20 – bastardsage ERWR Eriogonum wrightii 5–15 – fairyduster CAER Calliandra eriophylla 5–15 – whitethorn acacia ACCO2 Acacia constricta 5–15 – desert lavender HYEM Hyptis emoryi 5–15 – San Felipe dogweed ADPO Adenophyllum porophylloides 5–15 – American threefold TRCA8 Trixis californica 0–15 – Wright's beebrush ALWR Aloysia wrightii 5–10 – sweetbush BEJU Bebbia juncea 5–10 – pelotazo ABIN Abutilon incanum 5–10 – woody crinklemat TICAC Tiquilia canescens var. canescens 0–10 – ragged rockflower CRBI2 Crossosoma bigelovii 5–10 – starry bedstraw GASTE2 Galium stellatum ssp. eremicum 0–5 – 10 Succulents 5–23 saguaro CAGI10 Carnegiea gigantea 2–5 – buckhorn cholla CYACA2 Cylindropuntia acanthocarpa var. acanthocarpa 0–2 – teddybear cholla CYBI9 Cylindropuntia bigelovii 1–2 – Wiggins' cholla CYEC3 Cylindropuntia echinocarpa 0–2 – Christmas cactus CYLE8 Cylindropuntia leptocaulis 1–2 – Engelmann's hedgehog cactus ECEN Echinocereus engelmannii 1–2 – California barrel cactus FECYC Ferocactus cylindraceus var. cylindraceus 1–2 – candy barrelcactus FEWI Ferocactus wislizeni 1–2 – Graham's nipple cactus MAGR9 Mammillaria grahamii 1–2 – common fishhook cactus MATE4 Mammillaria tetrancistra 1–2 – beavertail pricklypear OPBA2 Opuntia basilaris 1–2 – dollarjoint pricklypear OPCH Opuntia chlorotica 1–2 – cactus apple OPEN3 Opuntia engelmannii 1–2 – desert agave AGDE Agave deserti 0–2 – Tree9 Trees 23–45 blue paloverde PAFL6 Parkinsonia florida 12–23 – yellow paloverde PAMI5 Parkinsonia microphylla 12–23 – Interpretations
Animal community
This site has less sloping areas of hills that are easier for animals to travel. Fencing and water improvements are needed to improve distribution and utilization. Grazing should be deferred during the spring and summer rains to provide for good growth of the grasses and browse to improve condition.
Forage diversity is good but a lack of natural water and cover for larger wildlife animals, this is provided by associated canyon bottoms. Water developments are very important to wildlife on this site.Recreational uses
Recreation activity on this site is restricted in the hot summer months of June through August. Steep sharp ridges limit some activities. There is a good variety of desert shrubs and cacti with flowers during certain times of the year and provide good color contrast against the schist outcrops. Activities include horseback riding, wildlife observation, hunting, hiking and photography.
Other products
In some areas there is mining as a use.
Supporting information
Type locality
Location 1: Maricopa County, AZ Township/Range/Section T3N R6E S35 General legal description Salt River Indian Reservation. Also located in Sitgreaves-Red Hill allotment, Belmont Mountains Sec 32, T4N, R6W and Ives Peak - Buckskin Mountains Sec 3, T9N, R13W. Contributors
Karlynn Huling
Larry D. EllicottRangeland 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, Shai Schendel, Scott Stratton, Dan Robinett, Emilio Carrillo Contact for lead author NRCS Tucson Area Office Date 12/14/2005 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
5-8 feet apart -
Presence of water flow patterns:
very discontinuous, hard to observe due to high gravel and rock cover. -
Number and height of erosional pedestals or terracettes:
Erosional pedestals are very infrequent. Accumulated pedestals are 0-1/2 inch high. Terracettes are only formed by rock fragments. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
1-2% (Low values due to high rock and gravel cover). 2-3% woody litter, 95-97% rock fragment cover. -
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):
Most litter size classes stay in place due to high rock and gravel cover. -
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 1-3 in perennial plant interspaces, 4-5 under shrub canopies. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
channery; thickness to 2 inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
8-10% canopy: 85% half shrubs, 11% shrubs, 4% trees. Lichens and moss cover 10-15% of soil surface. 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 -
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:
subshrubs > annuals > shrubs > treesSub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
30% mortality of half shrubs ad shrubs. 100% mortality of perennial grasses and forbs. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
300 lbs/ac unfavorable precipitation, 500 lbs/ac normal precipitation, 800 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:
Sahara mustard, Lonon rocket, buffelgrass, red brome, filaree -
Perennial plant reproductive capability:
No impaired for shrubs; drought impaired for perennial grasses and forbs.
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