Natural Resources
Conservation Service
Ecological site R040XB202AZ
Paralithic Hills 7"-10" p.z.
Accessed: 11/24/2024
General information
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.
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 microphylla |
|---|---|
| Shrub |
(1) Encelia farinosa |
| Herbaceous |
(1) Muhlenbergia porteri |
Physiographic features
This site occurs on hillslopes and ridgetops. Slopes are from 15 to 65%. Elevations range from 1100 to 2500 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Hill
(2) Ridge |
|---|---|
| Elevation | 335 – 762 m |
| Slope | 15 – 65% |
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) | 254 mm |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
These are shallow soils formed on schist and limy volcanic, metamorphic, or conglomerate parent materials. Soils are calcareous and lime is found in the parent material as well. They are coarse textured, have well developed gravel covers, but lack the stone and cobble covers of other hill sites. Rock outcrop makes up a small perentage of the area. Plant-soil moisture relationships are poor. Parent material kind includes residuum. Parent material origin includes granodiorite, other metamorphic rock and conglomerate. Surface texture includes cobbly, very cobbly, and stony.
Soils mapped on this site include: in
SSA-645 Aguila-Carefree area MU's Beeline-9 & Lomitas(calcareous phase)-51;
SSA-653 Gila Bend-Ajo area MU's Hyder(non cobbly)-40 & 56.
Table 4. Representative soil features
| Parent material |
(1)
Alluvium
–
basic volcanic breccia
(2) Residuum – conglomerate |
|---|---|
| Surface texture |
(1) Very gravelly sandy loam (2) Extremely gravelly loam (3) Cobbly |
| Family particle size |
(1) Loamy |
| Drainage class | Well drained |
| Permeability class | Moderately rapid |
| Soil depth | 10 – 51 cm |
| Surface fragment cover <=3" | 35 – 65% |
| Surface fragment cover >3" | 1 – 15% |
| Available water capacity (0-101.6cm) |
0.51 – 4.06 cm |
| Calcium carbonate equivalent (0-101.6cm) |
2 – 10% |
| Electrical conductivity (0-101.6cm) |
0 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 |
| Soil reaction (1:1 water) (0-101.6cm) |
7.9 – 8.4 |
| Subsurface fragment volume <=3" (Depth not specified) |
35 – 65% |
| Subsurface fragment volume >3" (Depth not specified) |
1 – 15% |
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
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 text
Ecosystem states
State 1 submodel, plant communities
State 1
Historical Climax Plant Community
Community 1.1
Historical Climax Plant Community
The potential plant community is a diverse mixture of desert trees, shrubs, cacti, and annual grasses and perennial forbs. The aspect is shrubland. Continuous heavy grazing can remove perennial forbs and grasses from the plant community. Gravel cover is continuous but size may be lacking to prevent erosion on steep slopes. Gravel cover averages 90%. Basal cover of perennial vegetation averages 2% and percent of bare ground is about 8. Cryptogam cover on the bare ground portion runs from low to moderate. Plant populations of major species range from 100 to 450 per acre for brittlebush, 40 to 160 for creosotebush, 50 to 150 for paloverde, 1 to 10 for saguaro, 1 to 30 for ocotillo, 20 to 80 for wolfberry, and 50 to 200 for chola species. Buckhorn cholla tends to predominate on north slopes and teddybear cholla on south slopes. Desert globemallow tends to predominate on northern exposures and brittlebush on southern exposures. Both species are very sensitive to drought on this site and it is not uncommon to have 50-75% mortality of these two species after a severe drought period. A wet summer following a drought induced die-off of shrubs will result in an abundance of annual grasses like little seed muhly, mexican sprangletop, needle grama, and six week threeawn giving the site a grassy appearance. This is a temporary condition that changes as brittlebush and globemallow regain their predominance in the community.
Figure 4. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
|---|---|---|---|
| Shrub/Vine | 278 | – | 429 |
| Tree | 278 | – | 429 |
| Grass/Grasslike | 26 | – | 151 |
| Forb | 26 | – | 76 |
| Total | 608 | – | 1085 |
Additional community tables
Table 6. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | 6–22 | |||||
| bush muhly | MUPO2 | Muhlenbergia porteri | 0–3 | – | ||
| low woollygrass | DAPU7 | Dasyochloa pulchella | 0–2 | – | ||
| slim tridens | TRMU | Tridens muticus | 0–2 | – | ||
| Arizona cottontop | DICA8 | Digitaria californica | 0–1 | – | ||
| nineawn pappusgrass | ENDE | Enneapogon desvauxii | 0–1 | – | ||
| tanglehead | HECO10 | Heteropogon contortus | 0–1 | – | ||
| big galleta | PLRI3 | Pleuraphis rigida | 0–1 | – | ||
| purple threeawn | ARPU9 | Aristida purpurea | 0–1 | – | ||
| Fendler's threeawn | ARPUF | Aristida purpurea var. fendleriana | 0–1 | – | ||
| blue threeawn | ARPUN | Aristida purpurea var. nealleyi | 0–1 | – | ||
| Parish's threeawn | ARPUP5 | Aristida purpurea var. parishii | 0–1 | – | ||
| Wright's threeawn | ARPUW | Aristida purpurea var. wrightii | 0–1 | – | ||
| spidergrass | ARTE3 | Aristida ternipes | 0–1 | – | ||
| spidergrass | ARTEG | Aristida ternipes var. gentilis | 0–1 | – | ||
| 2 | 22–123 | |||||
| sixweeks fescue | VUOC | Vulpia octoflora | 4–22 | – | ||
| sixweeks threeawn | ARAD | Aristida adscensionis | 0–11 | – | ||
| prairie threeawn | AROL | Aristida oligantha | 0–11 | – | ||
| needle grama | BOAR | Bouteloua aristidoides | 0–11 | – | ||
| sixweeks grama | BOBA2 | Bouteloua barbata | 0–11 | – | ||
| Eastwood fescue | VUMIC | Vulpia microstachys var. ciliata | 0–11 | – | ||
| Pacific fescue | VUMIP | Vulpia microstachys var. pauciflora | 0–11 | – | ||
| Rothrock's grama | BORO2 | Bouteloua rothrockii | 0–6 | – | ||
| tufted lovegrass | ERPEP2 | Eragrostis pectinacea var. pectinacea | 0–2 | – | ||
| Mexican sprangletop | LEFUU | Leptochloa fusca ssp. uninervia | 0–2 | – | ||
| mucronate sprangeltop | LEPAB | Leptochloa panicea ssp. brachiata | 0–2 | – | ||
| delicate muhly | MUFR | Muhlenbergia fragilis | 0–2 | – | ||
| littleseed muhly | MUMI | Muhlenbergia microsperma | 0–2 | – | ||
| witchgrass | PACA6 | Panicum capillare | 0–2 | – | ||
| Bigelow's bluegrass | POBI | Poa bigelovii | 0–1 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 0–1 | – | ||
|
Forb
|
||||||
| 3 | 6–22 | |||||
| narrowleaf silverbush | ARLA12 | Argythamnia lanceolata | 0–3 | – | ||
| California fagonbush | FALA | Fagonia laevis | 0–2 | – | ||
| lacy tansyaster | MAPIP4 | Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida | 0–2 | – | ||
| Newberry's velvetmallow | HONE | Horsfordia newberryi | 0–2 | – | ||
| slender janusia | JAGR | Janusia gracilis | 0–1 | – | ||
| Parry's false prairie-clover | MAPA7 | Marina parryi | 0–1 | – | ||
| rough menodora | MESC | Menodora scabra | 0–1 | – | ||
| slender poreleaf | POGR5 | Porophyllum gracile | 0–1 | – | ||
| Coues' cassia | SECO10 | Senna covesii | 0–1 | – | ||
| brownplume wirelettuce | STPA4 | Stephanomeria pauciflora | 0–1 | – | ||
| desert rosemallow | HICO | Hibiscus coulteri | 0–1 | – | ||
| paleface | HIDE | Hibiscus denudatus | 0–1 | – | ||
| poreleaf dogweed | ADPO2 | Adenophyllum porophyllum | 0–1 | – | ||
| trailing windmills | ALIN | Allionia incarnata | 0–1 | – | ||
| New Mexico silverbush | ARNE2 | Argythamnia neomexicana | 0–1 | – | ||
| whitemargin sandmat | CHAL11 | Chamaesyce albomarginata | 0–1 | – | ||
| desert trumpet | ERIN4 | Eriogonum inflatum | 0–1 | – | ||
| 4 | 6–50 | |||||
| desert Indianwheat | PLOV | Plantago ovata | 0–11 | – | ||
| combseed | PECTO | Pectocarya | 0–6 | – | ||
| bristly fiddleneck | AMTE3 | Amsinckia tessellata | 0–6 | – | ||
| cryptantha | CRYPT | Cryptantha | 0–3 | – | ||
| western tansymustard | DEPI | Descurainia pinnata | 0–2 | – | ||
| tall mountain larkspur | DESC | Delphinium scaposum | 0–1 | – | ||
| bluedicks | DICA14 | Dichelostemma capitatum | 0–1 | – | ||
| miniature woollystar | ERDI2 | Eriastrum diffusum | 0–1 | – | ||
| common woolly sunflower | ERLA6 | Eriophyllum lanatum | 0–1 | – | ||
| Texas stork's bill | ERTE13 | Erodium texanum | 0–1 | – | ||
| California poppy | ESCAM | Eschscholzia californica ssp. mexicana | 0–1 | – | ||
| Gordon's bladderpod | LEGO | Lesquerella gordonii | 0–1 | – | ||
| shaggyfruit pepperweed | LELA | Lepidium lasiocarpum | 0–1 | – | ||
| Bigelow's linanthus | LIBI2 | Linanthus bigelovii | 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 | – | ||
| hoary tansyaster | MACAC3 | Machaeranthera canescens ssp. canescens var. canescens | 0–1 | – | ||
| blazingstar | MENTZ | Mentzelia | 0–1 | – | ||
| green carpetweed | MOVE | Mollugo verticillata | 0–1 | – | ||
| glandular threadplant | NEGL | Nemacladus glanduliferus | 0–1 | – | ||
| desert tobacco | NIOB | Nicotiana obtusifolia | 0–1 | – | ||
| evening primrose | OENOT | Oenothera | 0–1 | – | ||
| Emory's rockdaisy | PEEM | Perityle emoryi | 0–1 | – | ||
| manybristle chinchweed | PEPA2 | Pectis papposa | 0–1 | – | ||
| phacelia | PHACE | Phacelia | 0–1 | – | ||
| New Mexico plumeseed | RANE | Rafinesquia neomexicana | 0–1 | – | ||
| chia | SACO6 | Salvia columbariae | 0–1 | – | ||
| smooth threadleaf ragwort | SEFLM | Senecio flaccidus var. monoensis | 0–1 | – | ||
| sleepy silene | SIAN2 | Silene antirrhina | 0–1 | – | ||
| Coulter's globemallow | SPCO2 | Sphaeralcea coulteri | 0–1 | – | ||
| woollyhead neststraw | STMI2 | Stylocline micropoides | 0–1 | – | ||
| bigseed alfalfa dodder | CUIN | Cuscuta indecora | 0–1 | – | ||
| hairy prairie clover | DAMO | Dalea mollis | 0–1 | – | ||
| American wild carrot | DAPU3 | Daucus pusillus | 0–1 | – | ||
| desert larkspur | DEPA | Delphinium parishii | 0–1 | – | ||
| weakleaf bur ragweed | AMCO3 | Ambrosia confertiflora | 0–1 | – | ||
| carelessweed | AMPA | Amaranthus palmeri | 0–1 | – | ||
| milkvetch | ASTRA | Astragalus | 0–1 | – | ||
| desert marigold | BAMU | Baileya multiradiata | 0–1 | – | ||
| Coulter's spiderling | BOCO2 | Boerhavia coulteri | 0–1 | – | ||
| Tucson Mountain spiderling | BOME | Boerhavia megaptera | 0–1 | – | ||
| California suncup | CACA32 | Camissonia californica | 0–1 | – | ||
| fringed redmaids | CACI2 | Calandrinia ciliata | 0–1 | – | ||
| exserted Indian paintbrush | CAEXE | Castilleja exserta ssp. exserta | 0–1 | – | ||
| white tackstem | CAWR | Calycoseris wrightii | 0–1 | – | ||
| brittle spineflower | CHBR | Chorizanthe brevicornu | 0–1 | – | ||
| pebble pincushion | CHCA | Chaenactis carphoclinia | 0–1 | – | ||
| goosefoot | CHENO | Chenopodium | 0–1 | – | ||
| hyssopleaf sandmat | CHHY3 | Chamaesyce hyssopifolia | 0–1 | – | ||
| devil's spineflower | CHRI | Chorizanthe rigida | 0–1 | – | ||
| Esteve's pincushion | CHST | Chaenactis stevioides | 0–1 | – | ||
| New Mexico thistle | CINE | Cirsium neomexicanum | 0–1 | – | ||
|
Shrub/Vine
|
||||||
| 5 | 101–168 | |||||
| brittlebush | ENFA | Encelia farinosa | 45–90 | – | ||
| desert globemallow | SPAM2 | Sphaeralcea ambigua | 34–78 | – | ||
| 6 | 22–50 | |||||
| 7 | 50–123 | |||||
| ocotillo | FOSP2 | Fouquieria splendens | 11–56 | – | ||
| creosote bush | LATR2 | Larrea tridentata | 6–34 | – | ||
| water jacket | LYAN | Lycium andersonii | 6–17 | – | ||
| Fremont's desert-thorn | LYFR | Lycium fremontii | 6–17 | – | ||
| 8 | 6–22 | |||||
| beavertail pricklypear | OPBA2 | Opuntia basilaris | 0–2 | – | ||
| cactus apple | OPEN3 | Opuntia engelmannii | 0–1 | – | ||
| senita cactus | PASC14 | Pachycereus schottii | 0–1 | – | ||
| organpipe cactus | STTH3 | Stenocereus thurberi | 0–1 | – | ||
| Engelmann's hedgehog cactus | ECEN | Echinocereus engelmannii | 0–1 | – | ||
| Leconte's barrel cactus | FECYL | Ferocactus cylindraceus var. lecontei | 0–1 | – | ||
| Emory's barrel cactus | FEEM | Ferocactus emoryi | 0–1 | – | ||
| candy barrelcactus | FEWI | Ferocactus wislizeni | 0–1 | – | ||
| Thornber's nipple cactus | MATH | Mammillaria thornberi | 0–1 | – | ||
| 9 | 22–50 | |||||
| triangle bur ragweed | AMDE4 | Ambrosia deltoidea | 2–9 | – | ||
| burrobush | AMDU2 | Ambrosia dumosa | 2–9 | – | ||
| sangre de cristo | JACA2 | Jatropha cardiophylla | 0–6 | – | ||
| littleleaf ratany | KRER | Krameria erecta | 2–6 | – | ||
| white ratany | KRGR | Krameria grayi | 2–6 | – | ||
| American threefold | TRCA8 | Trixis californica | 0–3 | – | ||
| Coulter's brickellbush | BRCO | Brickellia coulteri | 0–2 | – | ||
| rush milkweed | ASSU | Asclepias subulata | 0–2 | – | ||
| sweetbush | BEJU | Bebbia juncea | 0–1 | – | ||
| catclaw acacia | ACGR | Acacia greggii | 0–1 | – | ||
| Nevada jointfir | EPNE | Ephedra nevadensis | 0–1 | – | ||
| starry bedstraw | GASTE2 | Galium stellatum ssp. eremicum | 0–1 | – | ||
| desert lavender | HYEM | Hyptis emoryi | 0–1 | – | ||
| giant salvinia | SABI9 | Salvinia biloba | 0–1 | – | ||
| woody crinklemat | TICAC | Tiquilia canescens var. canescens | 0–1 | – | ||
| Parish's goldeneye | VIPA14 | Viguiera parishii | 0–1 | – | ||
|
Tree
|
||||||
| 10 | 22–50 | |||||
| yellow paloverde | PAMI5 | Parkinsonia microphylla | 17–34 | – | ||
| desert ironwood | OLTE | Olneya tesota | 11–28 | – | ||
Interpretations
Animal community
Steep slopes and gravelly surfaces hinder livestock distribution. Stocker cattle are best adapted to use this site. The plant community provides limited amounts of useable forage in the winter-spring periods. Natural water is unavailable on this site.
Water developments are very important to wildlife species on this site. Cover, diversity, and topography make this site home to a variety of desert animals. Large mammals use this site seasonally unless permanent water supplies exist in the area.
Other information
T&E: Leptoncycteris curasoae yerbe buena
(lesser long-nosed bat)
Supporting information
Type locality
| Location 1: Maricopa County, AZ | |
|---|---|
| Township/Range/Section | T3S R6W S16 |
| General legal description | Buckeye FO - Woolsey Peak |
| Location 2: Pima County, AZ | |
| Township/Range/Section | T9S R5E S4 |
| General legal description | Sells FO - Tat Momolikot Mountains |
| Location 3: Maricopa County, AZ | |
| Township/Range/Section | T3S R7E S28 |
| General legal description | Chandler FO - Santan Mountains |
| Location 4: Maricopa County, AZ | |
| Township/Range/Section | T6N R1E S30 |
| General legal description | Phoenix FO - Lake Pleasant Reg. Park |
| Location 5: Pima County, AZ | |
| Township/Range/Section | T12S R3E S33 |
| General legal description | Sells FO - Gu Achi District, Anegam Hills |
| Location 6: Pima County, AZ | |
| Township/Range/Section | T14S R5W S11 |
| General legal description | Tucson FO - Organ Pipe National Monument, Gunsight Hills |
Contributors
Dan Robinett
Larry D. Ellicott
Steve Barker
Rangeland 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 | 12/28/2005 |
| Approved by | S. Cassady |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Common on this site only in areas where rock and gravel cover is low. -
Presence of water flow patterns:
Water flow patterns are common, continuous adn cover 15-20% of area. -
Number and height of erosional pedestals or terracettes:
None. -
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:
No evidence of soil movement by wind. -
Amount of litter movement (describe size and distance expected to travel):
Herbaceous litter can move by wind and water. Woody litter remains under shrub canopies. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface resistance to erosion is good under shrub canopies & areas with high rock and gravel cover to moderate in soil interspaces due to crusts formed by raindrop impact. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
fine granular; to 2 inches thick. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Canopy 10-15%; 70-80% shrubs, 5% trees and 10-15% succulents. 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 > large shrubs > winter annuals > summer annulas > perennial grasses and forbs > crytogams (Note: in El Nino years annual forbs and grasses are #1 in above ground weight)Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
0-50% canopy mortality -
Average percent litter cover (%) and depth ( in):
Herbaceous litter is not persistent on the site and may be 20-60% in El Nino years. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
250 lbs/ac unfavorable precipitation; 450 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 (potential) -
Perennial plant reproductive capability:
Not impaired for shrubs, drought impaired for perennial grasses and forbs.
Print Options
Sections
Font
Other
The 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.
Click on box and path labels to scroll to the respective text.