Natural Resources
Conservation Service
Ecological site R070BY065NM
Gravelly
Last updated: 9/12/2023
Accessed: 12/21/2024
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.
Ecological site concept
This site occurs on very deep soils that have high fragment content in the surface and/or subsurface horizons. Subsurface horizons have high calcium carbonate equivalent.
This site occurs on alluvial landforms such as stream terraces and fan remnants. Slopes range from 0 to 35 percent.
The Gravelly ecological site typically occurs on ridges and gravelly alluvial terraces adjacent to the Loamy or Sandy Loam sites.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Yucca glauca |
| Herbaceous |
(1) Bouteloua eriopoda |
Physiographic features
Legacy narrative:
"This site occurs on loamy unconsolidated eolian, lacustrine, or fluvial sediments that are on nearly level to undulating, concave plains in broad, shallow basins, terraces along drainageways and on the fans at the foot of escarpments. Slopes are convex and range from 0 to 35 percent. Elevation ranges from approximately 3,800 to 5,300 feet above sea level. Aspect varies and significantly different only on the north-facing steep slopes. The mean annual precipitation is 483 millimeters (19 inches) and the mean annual air temperature is 16 degrees C (61 degrees F)."
Note that the Concept section includes "ridges" as settings for this site. Presumably, "ridges" in this context are elongated highs on alluvial features rather than structural ridges.
Table 2. Representative physiographic features
| Landforms |
(1)
Alluvial fan
(2) Stream terrace (3) Plain |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 3,800 – 5,300 ft |
| Slope | 35% |
| Aspect | Aspect is not a significant factor |
Climatic features
The climate of this area can be classified as “semi-arid continental”.
Annual average precipitation ranges from 11 to 16 inches. Roughly 78 percent of the moisture falls during the 6-month period of May through October. Most of this summer precipitation falls in the form of brief and heavy afternoon and evening thunderstorms. Hail may accompany the more severe summer storms. In the winter, there is normally only one day a month when as much as one-tenth inch of moisture falls, usually in the form of snow. Snow seldom lies on the ground for more than a few days.
Temperatures are characterized by a distinct seasonal change and large annual and diurnal temperature ranges. Summers are moderately warm. Maximum temperature average above 90 degrees F from July to August, and an average summer includes about 80 days with high readings exceeding 90 degrees F and 10 days with readings above 100 degrees F. Temperatures usually fall rapidly after sundown and lows average 60 degrees F on most summer nights. Winters are mild, sunny, and dry. Daytime shade temperatures in midwinter usually rise to the 50’s. However, freezing temperatures normally occur at night from mid-November to mid-March.
The freeze-free season ranges from 196 to 218 days. Dates of the last freeze range from April 11th to April 17th and the first freeze ranges from October 20th to October 25th.
Both temperature and rainfall distribution favor warm-season, perennial plant communities in the area. However, sufficient late winter and early spring moisture allows cool-season species to occupy a minor component within the plant community.
Climate data was obtained from http://www.wrcc.dri.edu/summary/climsmnm.html web site. Data were interpreted utilizing NM Climate Summarizer spreadsheet.
Table 3. Representative climatic features
| Frost-free period (average) | 192 days |
|---|---|
| Freeze-free period (average) | 218 days |
| Precipitation total (average) | 16 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
This site is not influenced by water from a wetland or stream.
Soil features
Soils are deep to very deep. Surface texture is fine sandy loam, gravelly loam, gravelly loamy fine sand, very gravelly fine sandy loam, very gravelly sandy clay loam, or very gravelly loam. The subsurface layers are gravelly loam, loam, gravelly loamy fine sand, very gravelly fine sandy loam, very gravelly sandy clay loam, extremely gravelly sandy loam, or very gravelly loam. Calcium carbonate equivalent ranges from 15 to 40 percent in the lower horizons. Soils have moderate permeability. The available water-holding capacity is medium. The effective rooting depth is from 40 to 72 inches. Air and water move freely through these soils.
Minimum and maximum values listed below represent the characterisitc soils for this site.
Characteristic soils:
Bascom
Gallegos
Gallen
Torriorthents
Table 4. Representative soil features
| Surface texture |
(1) Gravelly sandy loam (2) Very gravelly fine sandy loam (3) Loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Moderately slow to moderately rapid |
| Soil depth | 41 – 72 in |
| Surface fragment cover <=3" | 10 – 40% |
| Surface fragment cover >3" | 15% |
| Available water capacity (0-40in) |
6 – 9 in |
| Calcium carbonate equivalent (0-40in) |
7 – 40% |
| Electrical conductivity (0-40in) |
8 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
10 |
| Soil reaction (1:1 water) (0-40in) |
6.6 – 9 |
| Subsurface fragment volume <=3" (Depth not specified) |
35 – 75% |
| Subsurface fragment volume >3" (Depth not specified) |
30% |
Ecological dynamics
This site is dominated by warm-season short and mid-grasses, with scattered shrubs and forbs. Grasses make up approximately 75 percent of the annual vegetative production. Shrubs and forbs are evenly distributed and can make up an important portion of the plant community. Black grama, blue grama, and sideoats grama are the dominant grasses of the reference plant community. Seed dispersal by livestock and wildlife, decreased fire frequency, and loss of grass cover may facilitate an increase in woody species.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Mixed-Shrub Grassland
This state contains a mix of shrubs and grasses.
Community 1.1
Mixed-Shrub Grassland
In the reference plant community, black grama, blue grama, and sideoats grama are the dominant grasses. Common forbs include globemallow, species of buckwheat, paper flower, and plains zinnia. Soapweed yucca, catclaw mimosa, feather dalea, and broom snakeweed are a few of the shrubs common to this site. Continuous heavy grazing pressure can cause a decrease in black grama and sideoats grama and result in communities dominated by blue grama, with galleta, threeawns, sand dropseed, ring muhly, and broom snakeweed becoming sub-dominant. Other subordinate species that typically increase in representation include hairy grama, wolfstail, and rough tridens. Diagnosis: Species of grama dominate the site. Grass cover is uniform with few large bare areas. Shrubs are present and evenly distributed. There is little evidence of erosion.
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 | 340 | 710 | 1090 |
| Forb | 70 | 140 | 220 |
| Shrub/Vine | 40 | 90 | 140 |
| Total | 450 | 940 | 1450 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 5-10% |
| Grass/grasslike foliar cover | 5-15% |
| Forb foliar cover | 1-2% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 1-5% |
| Surface fragments >0.25" and <=3" | 35-60% |
| Surface fragments >3" | 15-35% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 20-30% |
Figure 5. Plant community growth curve (percent production by month). NM4014, R070BY065NM Gravelly Reference State. R070BY065NM Gravelly Reference State Grassland with warm-season short and mid-grasses. Shrubs and forbs are an important component..
| 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 | 3 | 5 | 5 | 10 | 25 | 30 | 15 | 7 | 0 | 0 |
State 2
Woody-Encroached
This state a marked increase in cover by woody plants.
Community 2.1
Woody-Encroached
This phase is characterized by the noticeable increase of woody species including mesquite, catclaw acacia, catclaw mimosa, and juniper. These species may occur individually or in combination. Mesquite, catclaw acacia, and catclaw mimosa tend to be more widespread across the extent of the Gravelly site, while increases in juniper may be more representative of the northern portion of this resource area. Blue grama is typically the dominant grass with threeawns, galleta, ring muhly, and sand dropseed occurring as sub-dominants. Diagnosis: Woody species, including mesquite, catclaw acacia, catclaw mimosa, or juniper are found at increased densities. Grass cover is patchy with frequent large bare areas present. Rills and small gullies may be present, especially on the steeper sideslopes. Transition to Woody-Encroached (1a) Seed dispersal, loss of grass cover, and decreased fire frequency are believed to initiate this transition. Seed dispersal by livestock and wildlife may be a key factor in facilitating the encroachment of woody species. The seeds of mesquite and catclaw mimosa are highly palatable to livestock and wildlife. Birds and numerous small mammals consume and transport juniper berries and catclaw acacia seed. A reduction in grass cover can provide competition-free areas for the establishment of woody species. It also can reduce fine fuels, decrease burn intensity, and negatively affect the site's ability to carry fire. Fire generally causes high mortality rates for oneseed juniper. Conversely, mesquite, catclaw mimosa, and catclaw acacia are resistant to, and typically re-sprout following, fire. However, periodic fire may have helped to check the encroachment of these species by killing young seedlings, disrupting seed production cycles, and damaging the plants, making them more susceptible to disease and insects. Key indicators of approach to transition: Decrease or change in distribution of grass cover. Increase in amount of woody seedlings. Transition back to Mixed-Shrub Grassland (1b) Brush control is necessary to reduce the competitive influence of woody species and assist with grass reestablishment. Prescribed grazing will help ensure proper forage use following brush control.
Figure 6. Plant community growth curve (percent production by month). NM4014, R070BY065NM Gravelly Reference State. R070BY065NM Gravelly Reference State Grassland with warm-season short and mid-grasses. Shrubs and forbs are an important component..
| 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 | 3 | 5 | 5 | 10 | 25 | 30 | 15 | 7 | 0 | 0 |
Additional community tables
Table 7. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | 140–170 | |||||
| black grama | BOER4 | Bouteloua eriopoda | 143–171 | – | ||
| 2 | 120–150 | |||||
| blue grama | BOGR2 | Bouteloua gracilis | 124–152 | – | ||
| 3 | 110–140 | |||||
| sideoats grama | BOCU | Bouteloua curtipendula | 114–143 | – | ||
| 4 | 50–70 | |||||
| New Mexico feathergrass | HENE5 | Hesperostipa neomexicana | 0–67 | – | ||
| James' galleta | PLJA | Pleuraphis jamesii | 0–67 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 0–67 | – | ||
| 5 | 30–50 | |||||
| threeawn | ARIST | Aristida | 0–48 | – | ||
| hairy grama | BOHI2 | Bouteloua hirsuta | 0–48 | – | ||
| little bluestem | SCSC | Schizachyrium scoparium | 0–48 | – | ||
| slim tridens | TRMUE | Tridens muticus var. elongatus | 0–48 | – | ||
| 6 | 10–30 | |||||
| plains bristlegrass | SEVU2 | Setaria vulpiseta | 10–29 | – | ||
| 7 | 20–30 | |||||
| squirreltail | ELEL5 | Elymus elymoides | 0–29 | – | ||
| common wolfstail | LYPH | Lycurus phleoides | 0–29 | – | ||
| ring muhly | MUTO2 | Muhlenbergia torreyi | 0–29 | – | ||
|
Forb
|
||||||
| 8 | 40–60 | |||||
| buckwheat | ERIOG | Eriogonum | 0–57 | – | ||
| Adonis blazingstar | MEMU3 | Mentzelia multiflora | 0–57 | – | ||
| whitestem paperflower | PSCO2 | Psilostrophe cooperi | 0–57 | – | ||
| globemallow | SPHAE | Sphaeralcea | 0–57 | – | ||
| desert zinnia | ZIAC | Zinnia acerosa | 0–57 | – | ||
| 9 | 40–60 | |||||
| Forb, perennial | 2FP | Forb, perennial | 38–57 | – | ||
| 10 | 30–50 | |||||
| Forb, annual | 2FA | Forb, annual | 29–48 | – | ||
|
Shrub/Vine
|
||||||
| 11 | 30–50 | |||||
| soapweed yucca | YUGL | Yucca glauca | 29–48 | – | ||
| 12 | 10–30 | |||||
| featherplume | DAFO | Dalea formosa | 0–29 | – | ||
| plains pricklypear | OPPO | Opuntia polyacantha | 0–29 | – | ||
| 13 | 10–20 | |||||
| prairie sagewort | ARFR4 | Artemisia frigida | 0–19 | – | ||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 0–19 | – | ||
| winterfat | KRLA2 | Krascheninnikovia lanata | 0–19 | – | ||
| 14 | 0–20 | |||||
| juniper | JUNIP | Juniperus | 0–19 | – | ||
| mesquite | PROSO | Prosopis | 0–19 | – | ||
Interpretations
Animal community
Habitat for Wildlife: This site provides habitat which supports a resident animal community characterized by pronghorn antelope, spotted skunk, desert cottontail, silky pocket mouse, Colorado chipmunk, ferruginous hawk, roadrunner, scaled quail, Great Plains toad, and fence lizard. There is seasonal use by mule deer.
Hydrological functions
The runoff curve numbers are determined by field investigations using hydrologic cover conditions and hydrologic soil groups.
Hydrologic Interpretations
Soil Series Hydrologic Group
Bascom --------------------------B
Gallegos ------------------------B
Gallen --------------------------B
Philder -------------------------D
Recreational uses
This site has limited recreation potential, largely due to the lack of surface water and shade. Screening is poor; camping is poor; hiking and picnicking are fair. Hunting for antelope is fair, and hunting for rabbits and upland game birds is fair to good. The natural beauty of the site is enhanced by the variety of plants that bloom from spring to early fall.
Wood products
This site produces no wood products.
Other products
Grazing: This site can be grazed during any season of the year by all classes of livestock, generally without regard to age. However, where slopes exceed 20 percent, livestock distribution becomes a problem and younger livestock will better utilize the steeper slopes. Due to the site’s potential to produce forbs, it may be better suited to sheep and antelope. Approximately 85 percent of the total annual yield is from species that furnish forage for grazing animals, and the variety of grasses, forbs, and shrubs furnish good nutrition for these animals during most of the year.
Continuous grazing by cattle will cause the site to deteriorate and become less productive. Species such as black grama, sideoats grama, New Mexico feathergrass, little bluestem, and winterfat will decrease in the percent composition. These will be replaced by plants such as galleta, sand dropseed, rough tridens, threeawns, ring muhly, catclaw acacia, broom snakeweed, juniper, and forbs. Mesquite will easily invade this site as it deteriorates. A system of deferred grazing, which varies the season of rest and grazing during successive years, is needed to improve or to maintain a healthy, well-balanced plant community. Deferment during different seasons of the year benefits different species. Winter rest will benefit woody species such as winterfat and feather dalea. Cattle show a definite preference to black grama during the late winter, and it can easily be overgrazed; winter rest will reduce the grazing pressure on this grass. Spring rest (April-June) will benefit species such as New Mexico feathergrass, bottlebrush squirreltail, and early forbs. Summer rest will benefit black grama, blue grama, sideoats grama, little bluestem, plains bristlegrass, and forbs. Summer rest will allow the cool-season species to complete their growth cycle. Fall rest allows the warm-season species to complete their growth cycle.
Other information
Guide to Suggested Initial Stocking Rate Acres per Animal Unit Month
Similarity Index Ac/AUM
100 - 76 2.9 – 4.7
75 – 51 3.4 – 7.0
50 – 26 4.4 – 12.0
25 – 0 12.0+
Supporting information
Inventory data references
Data collection for this site was performed in conjunction with the progressive soil surveys within the Pecos-Canadian Plains and Valleys, Major Land Resource Area 70 of New Mexico. This site has been mapped and correlated to soils in the following counties: San Miguel, Quay, Guadalupe, De Baca, and Chaves.
Other references
References.
1. Drewa, P.B., D.P.C. Peters, and K. M. Havstad. 2001 Fire grazing and honey mesquite invasion in black grama-dominated grasslands of the Chihuahuan Desert: a synthesis. Pages 31-39 in K.E.M. Galley and T.P. Wilson (eds.) Proceedings of the Invasive Species Workshop: the Role of fire in the Control and Spread of Invasive Species. Fire Conference 2000: the First National Congress on Fire Ecology, Prevention, and Management. Miscellaneous Publication No. 11, Tall Timbers Research Station, Tallahassee, FL.
2. Hastings, J. R. and R. M. Turner. 1965 The changing mile: An ecological study of vegetation
change with time in the lower mile of an arid and semiarid region. Tuscon AZ: University
of Arizona Press. 317 p.
3. Wright, H.A., S.C. Bunting, and L.F. Neuenschwander. 1976. Effect of fire on honey mesquite. Journal of Range Management 29:467-471.
Contributors
Christine Bishop
Don Sylvester
John Tunberg
Approval
Kendra Moseley, 9/12/2023
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) | |
|---|---|
| Contact for lead author | |
| Date | 09/13/2023 |
| Approved by | Kendra Moseley |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction 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:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
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:
-
Perennial plant reproductive capability:
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