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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
R040XA110AZ Limy Slopes 10"-13" p.z.
R040XA111AZ Limy Upland 10"-13" p.z.
R040XA106AZ Limy Upland, Deep 10"-13" p.z.
Similar sites
R038XA105AZ Limestone Hills 12-16" p.z.
R041XC307AZ Limestone Hills 12-16" p.z.
R041XB220AZ Limestone Hills 8-12" p.z.
Table 1. Dominant plant species
Tree (1) Parkinsonia microphylla
Shrub (1) Zinnia acerosa
Herbaceous (1) Bouteloua trifida
(2) Tridens muticusPhysiographic features
This site occurs in the upper elevations of the Sonoran Desert in southern Arizona. Limestone rock outcrops are associated with this site and may make up as much as 50% of the area. Slope aspect is site differentiating at elevations near land resource area boundaries. It occurs on steep hill-slopes and ridge-tops.
Table 2. Representative physiographic features
Landforms (1) Hill
(2) Ridge
(3) Mountain slope
Flooding frequency None Ponding frequency None Elevation 2000 – 4000 ft Slope 15 – 75 % Aspect N, E, S 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 shallow and very shallow soils over hard limestone bedrock. They are calcareous throughout and are very gravelly to cobbly. Plant-soil moisture relationships are poor but large areas of rock outcrop tend to magnify the amount of moisture received by soil areas. Soils mapped on this site include: SSA-669 Eastern Pima County MU Saguaro-71 & SSA-703 Tohono O'odham area MU Kohatk-39.
Table 4. Representative soil features
Surface texture (1) Very gravelly sandy loam
(2) Gravelly sandy loam
(3) Gravelly loam
Family particle size (1) Loamy
Drainage class Excessively drained to well drained Permeability class Rapid to moderately rapid Soil depth 5 – 20 in Surface fragment cover <=3" 30 – 60 % Surface fragment cover >3" 5 – 20 % Available water capacity
(0-40in)0.5 – 2 in Calcium carbonate equivalent
(0-40in)15 – 60 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 2 Soil reaction (1:1 water)
(0-40in)8 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)35 – 65 % Subsurface fragment volume >3"
(Depth not specified)0 – 10 % 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, Limestone Hills 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 is a diverse mixture of desert trees, shrubs, cacti, and perennial grasses and forbs. Most perennial species are well dispersed throughout the plant community. The aspect is shrubland.
With continuous heavy grazing, herbaceous and suffrutescent forage species are replaced by increases in shrubs, cacti and trees. Well developed gravel and cobble covers protect the soil from erosion and help protect forage species from heavy utilization. The large amount of rock outcrop on this site tends to magnify water received by adjacent soil areas.
The dynamics of Saguaro on this site is unlike the 200-300 year cycle found on deep upland sites in the Upper Sonoran desert. Saguaro recruitment can occur in any favorable year due to numerous rocky habitats favorable for establishment. Saguaro populations tend to be multi-aged and persistent on this site although very favorable years for establishment may result in very heavy stands on some slopes many years later.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)Shrub/Vine 100 250 345 Forb 18 75 175 Grass/Grasslike 5 75 170 Tree 50 100 150 Total 173 500 840 Table 6. Soil surface cover
Tree basal cover 0-0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 0-0% Forb basal cover 0-0% Non-vascular plants 0% Biological crusts 0-10% Litter 10-40% Surface fragments >0.25" and <=3" 30-60% Surface fragments >3" 10-30% Bedrock 10-20% Water 0% Bare ground 10-30% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 0-2% 0-10% 1-10% >0.5 <= 1 – 0-2% 1-5% 1-10% >1 <= 2 – 1-5% 0-1% 0-2% >2 <= 4.5 0-1% 1-5% 0-1% 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). AZ4011 , 40.1 10-13" p.z. hill 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 15 20 5 5 10 15 15 5 5 0 State 2
Native trees, cacti, shrubs and fireCommunity 2.1
Native trees, cacti, shrubs and fireThis plant community occurs as a result of a single hot season fire. Paloverde, ironwood and saguaro can be severely impacted and may take long periods of time (30-50 years) to recover to pre-fire levels. Perennial and annual grasses and forbs dominate the community for some time until shrubs like ocotillo, wolfberry and jojoba can recover.
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 3
Exotic perennial grasses with nativesCommunity 3.1
Exotic perennial grasses with nativesThis community occurs where bufflegrass and / or fountain grass invade the native plant community. These species occupy the niches of low shrubs like desert zinnia, brittlebush and grasses like red grama and slim tridens.
State 4
Exotic perennial grasses and fireCommunity 4.1
Exotic perennial grasses and fireThis community occurs where a native plant community that has been invaded by bufflegrass or fountain grass has burned one or more times. Increasing amounts of bufflegrass 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 5
Native plant community with exotic annualsCommunity 5.1
Native plant community with exotic annualsThis plant community occurs where the native community has been invaded by red brome and / or schismus. Red brome occupies the niche of the native winter annual forbs and grasses. This exotic annual grass will fluctuate from nearly nothing in a dry winter to dominance of the understory plant community in a El Nino winter.
State 6
Exotic annuals and fireCommunity 6.1
Exotic annuals and fireThis plant community occurs where a native plant community which has been invaded by red brome and / or schismus, and has burned repeatedly. As fires become more frequent the native trees, shrubs and succulents are removed from the plant community and red brome 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.
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 grasses 5–100 slim tridens TRMU Tridens muticus 1–35 – blue threeawn ARPUN Aristida purpurea var. nealleyi 1–30 – bush muhly MUPO2 Muhlenbergia porteri 1–30 – red grama BOTR2 Bouteloua trifida 0–25 – low woollygrass DAPU7 Dasyochloa pulchella 1–25 – black grama BOER4 Bouteloua eriopoda 0–20 – nineawn pappusgrass ENDE Enneapogon desvauxii 1–15 – purple threeawn ARPU9 Aristida purpurea 0–10 – slender grama BORE2 Bouteloua repens 0–5 – Hall's panicgrass PAHA Panicum hallii 0–5 – 2 Miscellaneous perennial grasses 0–25 sideoats grama BOCU Bouteloua curtipendula 0–10 – tanglehead HECO10 Heteropogon contortus 0–10 – plains bristlegrass SEVU2 Setaria vulpiseta 0–5 – Parish's threeawn ARPUP5 Aristida purpurea var. parishii 0–5 – Wright's threeawn ARPUW Aristida purpurea var. wrightii 0–5 – spidergrass ARTE3 Aristida ternipes 0–5 – cane bluestem BOBA3 Bothriochloa barbinodis 0–2 – Arizona cottontop DICA8 Digitaria californica 0–2 – squirreltail ELELE Elymus elymoides ssp. elymoides 0–2 – desert needlegrass ACSP12 Achnatherum speciosum 0–2 – Havard's threeawn ARHA3 Aristida havardii 0–2 – spike dropseed SPCO4 Sporobolus contractus 0–2 – sand dropseed SPCR Sporobolus cryptandrus 0–2 – 3 Annual grasses 0–45 sixweeks threeawn ARAD Aristida adscensionis 0–10 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 0–10 – Rothrock's grama BORO2 Bouteloua rothrockii 0–10 – sixweeks fescue VUOC Vulpia octoflora 0–10 – prairie threeawn AROL Aristida oligantha 0–5 – delicate muhly MUFR Muhlenbergia fragilis 0–3 – littleseed muhly MUMI Muhlenbergia microsperma 0–3 – Bigelow's bluegrass POBI Poa bigelovii 0–2 – Arizona signalgrass URAR Urochloa arizonica 0–2 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 0–2 – Arizona brome BRAR4 Bromus arizonicus 0–1 – needle grama BOAR Bouteloua aristidoides 0–1 – sixweeks grama BOBA2 Bouteloua barbata 0–1 – Forb4 Dominant perennial forbs 10–50 paleface HIDE Hibiscus denudatus 1–15 – slender janusia JAGR Janusia gracilis 2–15 – Parry's false prairie-clover MAPA7 Marina parryi 1–10 – rough menodora MESC Menodora scabra 0–10 – glandleaf milkwort POMA7 Polygala macradenia 1–10 – trailing windmills ALIN Allionia incarnata 1–10 – desert globemallow SPAM2 Sphaeralcea ambigua 1–10 – desert marigold BAMU Baileya multiradiata 1–5 – leatherweed CRPOP Croton pottsii var. pottsii 1–5 – lacy tansyaster MAPIP4 Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida 1–5 – Coues' cassia SECO10 Senna covesii 0–3 – desert trumpet ERIN4 Eriogonum inflatum 1–3 – white sagebrush ARLU Artemisia ludoviciana 0–3 – dense ayenia AYMI Ayenia microphylla 0–3 – New Mexico silverbush ARNE2 Argythamnia neomexicana 0–2 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 0–2 – narrowleaf silverbush ARLA12 Argythamnia lanceolata 0–2 – California fagonbush FALA Fagonia laevis 0–2 – Parry's beardtongue PEPA24 Penstemon parryi 0–2 – slender poreleaf POGR5 Porophyllum gracile 0–2 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 0–2 – plains blackfoot MELE2 Melampodium leucanthum 0–1 – scarlet spiderling BOCO Boerhavia coccinea 0–1 – 5 Ferns and fern allies 7–55 Arizona spikemoss SEAR2 Selaginella arizonica 5–30 – lipfern CHEIL Cheilanthes 1–10 – cliffbrake PELLA Pellaea 1–10 – cloak fern NOTHO Notholaena 0–5 – 6 Annual forbs and minor perennials 1–65 phacelia PHACE Phacelia 0–15 – desert Indianwheat PLOV Plantago ovata 0–10 – lyreleaf jewelflower STCA5 Streptanthus carinatus 0–10 – western tansymustard DEPI Descurainia pinnata 0–10 – cryptantha CRYPT Cryptantha 0–10 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–10 – Gordon's bladderpod LEGO Lesquerella gordonii 0–10 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–10 – exserted Indian paintbrush CAEXE Castilleja exserta ssp. exserta 0–10 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–5 – hairy prairie clover DAMO Dalea mollis 0–5 – thelypody THELY Thelypodium 0–5 – Texas stork's bill ERTE13 Erodium texanum 0–5 – chia SACO6 Salvia columbariae 0–2 – American wild carrot DAPU3 Daucus pusillus 0–2 – wishbone-bush MILAV Mirabilis laevis var. villosa 0–2 – Florida pellitory PAFL3 Parietaria floridana 0–1 – whitestem blazingstar MEAL6 Mentzelia albicaulis 0–1 – foothill deervetch LOHU2 Lotus humistratus 0–1 – Mexican fireplant EUHE4 Euphorbia heterophylla 0–1 – Parish's larkspur DEPAP3 Delphinium parishii ssp. parishii 0–1 – bluedicks DICAC5 Dichelostemma capitatum ssp. capitatum 0–1 – flatcrown buckwheat ERDE6 Eriogonum deflexum 0–1 – sleepy silene SIAN2 Silene antirrhina 0–1 – slimjim bean PHFI3 Phaseolus filiformis 0–1 – Arizona popcornflower PLAR Plagiobothrys arizonicus 0–1 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–1 – pricklyleaf dogweed THAC Thymophylla acerosa 0–1 – sand fringepod THCU Thysanocarpus curvipes 0–1 – desert mariposa lily CAKE Calochortus kennedyi 0–1 – whitemargin sandmat CHAL11 Chamaesyce albomarginata 0–1 – brittle spineflower CHBR Chorizanthe brevicornu 0–1 – hyssopleaf sandmat CHHY3 Chamaesyce hyssopifolia 0–1 – Palmer's Indian mallow ABPA Abutilon palmeri 0–1 – brownfoot ACWR5 Acourtia wrightii 0–1 – San Felipe dogweed ADPO Adenophyllum porophylloides 0–1 – tuber anemone ANTU Anemone tuberosa 0–1 – rockcress ARABI2 Arabis 0–1 – aster ASTER Aster 0–1 – hairyseed bahia BAAB Bahia absinthifolia 0–1 – Coulter's spiderling BOCO2 Boerhavia coulteri 0–1 – hoary bowlesia BOIN3 Bowlesia incana 0–1 – Arizona wrightwort CAAR7 Carlowrightia arizonica 0–1 – Shrub/Vine7 Dominant low shrubs 40–145 desert zinnia ZIAC Zinnia acerosa 20–40 – mariola PAIN2 Parthenium incanum 15–30 – woody crinklemat TICAC Tiquilia canescens var. canescens 5–25 – white ratany KRGR Krameria grayi 5–25 – fairyduster CAER Calliandra eriophylla 1–20 – featherplume DAFO Dalea formosa 1–10 – brittlebush ENFA Encelia farinosa 0–10 – whitestem paperflower PSCO2 Psilostrophe cooperi 1–10 – littleleaf ratany KRER Krameria erecta 1–10 – pelotazo ABIN Abutilon incanum 0–10 – triangle bur ragweed AMDE4 Ambrosia deltoidea 0–10 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–2 – American threefold TRCA8 Trixis californica 0–2 – 8 Dominant large shrubs 40–100 ocotillo FOSP2 Fouquieria splendens 15–50 – whitethorn acacia ACCO2 Acacia constricta 10–30 – creosote bush LATRT Larrea tridentata var. tridentata 10–25 – jojoba SICH Simmondsia chinensis 0–20 – 9 Miscellaneous shrubs 5–25 Wright's beebrush ALWR Aloysia wrightii 1–10 – Nevada jointfir EPNE Ephedra nevadensis 0–2 – fourwing saltbush ATCA2 Atriplex canescens 0–2 – Warnock's snakewood COWA Condalia warnockii 1–2 – Rio Grande saddlebush MOSC Mortonia scabrella 0–2 – Parish's goldeneye VIPA14 Viguiera parishii 0–2 – lotebush ZIOB Ziziphus obtusifolia 0–1 – littleleaf sumac RHMI3 Rhus microphylla 0–1 – spiny hackberry CEEH Celtis ehrenbergiana 0–1 – javelina bush COER5 Condalia ericoides 0–1 – knifeleaf condalia COSP3 Condalia spathulata 0–1 – desert lavender HYEM Hyptis emoryi 0–1 – sangre de cristo JACA2 Jatropha cardiophylla 0–1 – water jacket LYAN Lycium andersonii 0–1 – Arizona desert-thorn LYEX Lycium exsertum 0–1 – algerita MATR3 Mahonia trifoliolata 0–1 – catclaw acacia ACGR Acacia greggii 0–1 – 10 Succulents 15–75 saguaro CAGI10 Carnegiea gigantea 1–20 – buck-horn cholla CYAC8 Cylindropuntia acanthocarpa 1–15 – teddybear cholla CYBI9 Cylindropuntia bigelovii 0–10 – cactus apple OPEN3 Opuntia engelmannii 1–10 – purple pricklypear OPMA8 Opuntia macrocentra 0–10 – tulip pricklypear OPPH Opuntia phaeacantha 1–10 – banana yucca YUBA Yucca baccata 1–5 – Nichol's echinocactus ECHON Echinocactus horizonthalonius var. nicholii 0–5 – Bigelow's nolina NOBI Nolina bigelovii 0–5 – jumping cholla CYFU10 Cylindropuntia fulgida 0–5 – Christmas cactus CYLE8 Cylindropuntia leptocaulis 1–5 – staghorn cholla CYVE3 Cylindropuntia versicolor 0–5 – common sotol DAWH2 Dasylirion wheeleri 1–5 – desert agave AGDE Agave deserti 0–5 – Schott's century plant AGSC3 Agave schottii 0–5 – California barrel cactus FECY Ferocactus cylindraceus 0–2 – Emory's barrel cactus FEEM Ferocactus emoryi 0–2 – candy barrelcactus FEWI Ferocactus wislizeni 0–2 – Graham's nipple cactus MAGR9 Mammillaria grahamii 0–1 – Thornber's nipple cactus MATH Mammillaria thornberi 0–1 – rainbow cactus ECPE Echinocereus pectinatus 0–1 – desert woollystar ERER2 Eriastrum eremicum 0–1 – spinystar ESVIV Escobaria vivipara var. vivipara 0–1 – Scheer's beehive cactus COROS Coryphantha robustispina ssp. scheeri 0–1 – Engelmann's hedgehog cactus ECEN Echinocereus engelmannii 0–1 – redspine fishhook cactus ECER2 Echinomastus erectocentrus 0–1 – Tree11 Trees 50–150 yellow paloverde PAMI5 Parkinsonia microphylla 50–150 – velvet mesquite PRVE Prosopis velutina 0–10 – Arizona rosewood VACA5 Vauquelinia californica 0–10 – oneseed juniper JUMO Juniperus monosperma 0–10 – desert ironwood OLTE Olneya tesota 0–10 – 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
Herbaceous forage produced on this site is less palatable than that of other hill sites because high pH (due to lime) ties up essential plant nutrients and the very droughty soils make for a short green season. The plant community has a good variety of perennial grasses and low browse species for year-round use but steep, rocky slopes hinder utilization in the heat of summer. The site is best suited to cool season use with dry cows or stocker types. Slope aspect affects both the intensity of utilization as well as seasonal use patterns. South facing slopes are used more in winter due to warm temperatures and early greenup. North aspects, being shaded and cooler, are used more in the fall due to the longer green periods for forage species. This site tends to be dry even in the winter when other hill sites have canyon water.
Water developments are very important to wildlife on this site. Cover, forage plant diversity, and topography are good enough to make this site home to a wide variety of wildlife including the large desert mammals.Hydrological functions
This site is a fair producer of runoff due to steep slopes and shallow soils. Very gravelly and cobbly soil surfaces tend to hold water on the site. In areas with lots of rock outcrop there is a potential to develop water sources using rock catchments.
Recreational uses
Hunting, hiking, bird watching, photography, horseback riding, rock hounding, fossil collecting
Wood products
Some paloverde, ironwood and mesquite for camp-fires and branding fires.
Other products
Stones and cobbles; limestone for cement and flux. Saguaro ribs, cholla skeletons and rosewood. Tradtional foods like saguaro fruits, prickly pear tunas, cactus flower buds and jojoba nuts. Traditional herbs like coyote tobacco, mint bush, club moss, croton, creosotebush and limberbush.
Supporting information
Inventory data references
Range 417s include 2 in good condition
Type locality
Location 1: Pima County, AZ Township/Range/Section T12S R9E S36 General legal description Tucson Field Office: Waterman Mountains NW 1/4 sec. 36 Location 2: Pima County, AZ Township/Range/Section T9S R12E S22 General legal description Sells Field Office: Vekol Mountains NE 1/4 sec. 22 Location 3: Pima County, AZ Township/Range/Section T10S R17E S244 General legal description Tucson Field Office: Magma Copper Co Lime Quarry SE 1/4 sec. 244 Contributors
C.Michaels
Dan Robinett
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, Dan Robinett, Emilio Carrillo Contact for lead author NRCS Tucson Area Office Date 03/07/2005 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 seem to follow bedding planes, joints and fractures in the bedrock parent materials. -
Presence of water flow patterns:
Uncommon; probably cover no more than 10% of the area; discontinuous, usually less than 10-15 feet in length -
Number and height of erosional pedestals or terracettes:
Pedestals are uncommon on perennial grass and shrubs; terracettes uncommon. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
10-15% -
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):
most litter size classes stay in place -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Expect values of 1-3 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 thin platy to weak granular; color is 7.5-10YR6/4 dry; 7.5-10YR4/4 moist; thickness to 1 inch. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
canopy 15-25%, 70-80% of canopy cover is shrubs, 5% trees, and 10-15% succulents, 1-2% perennial grass. Cover is well dispersed throughout the 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 > shrubs & trees > annual grasses & forbs > succulents = perennial forbs = perennial grasses.Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
50% basal cover of perennial grassess has likely 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):
173 lbs/ac unfavorable precipitation; 500 lbs/ac normal precipitaton; 840 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:
bufflegrass, whitethorn, mesquite, prickly pear, cane cholla & ocotillo may increase -
Perennial plant reproductive capability:
not impaired for shrubs, drought impaired for perennial grasses and forbs.
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