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.
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): 036X–Southwestern Plateaus, Mesas, and Foothills
R036XB006NM – Loamy is an ecological site that is found on mesas, plateaus, fan remnant, terraces, dipslopes on cuestas, and broad upland valley sides in MLRA 36 (Southwestern Plateaus Mesas and Foothills). The southern portion MLRA 36 is illustrated yellow color on the map where this site occurs. The site concept was established in the Southwestern Plateaus. Mesas, and Foothills – Warm Semiarid Mesas and Plateaus LRU (Land Resource Area). This LRU has 10 to 16 inches of precipitation and has a mesic temperature regime. Lower part of MLRA 36 is dominated by summer precipitation for monsoons, unlike the upper part of MLRA 36 which is almost an equal split.
Classification relationships
NRCS & BLM:
Major Land Resource Area 36, Southwestern Plateaus Mesas and Foothills (United States Department of Agriculture, Natural Resources Conservation Service, 2006).
USFS:
313Bd Chaco Basin High Desert Shrubland and 313Be San Juan Basin North subsections < 313B Navaho Canyonlands Section < 313 Colorado Plateau Semi-Desert (Cleland, et al., 2007).
315Ha Central Rio Grande Intermontane, and 315Hb North Central Rio Grande Intermontane subsections <315H Central Rio Grande Intermontane Section < 315 Southwest Plateau and Plains Dry Steppe and Shrub (Cleland, et al., 2007).
315Ad Chupadera High Plains Grassland subsections <315A Pecos Valley Section < 315 Southwest Plateau and Plains Dry Steppe and Shrub (Cleland, et al., 2007).
331Jb San Luis Hills and 331Jd Southern San Luis Grasslands subsections <331J Northern Rio Grande Basin Section < 331 Great Plains- Palouse Dry Steppe (Cleland, et al., 2007).
20c Semiarid Benchlands and Canyonlands < 20 Colorado Plateaus < 10.1 Cold Deserts < 10 North American Deserts (Griffith, 2006).
22m Albuquerque Basin, 22i San Juan/Chaco Tablelands and Mesas, 22h North Central New Mexico Valleys and Mesas, 22f Taos Plateau, and 22g Rio Grande Floodplain, < 22 Arizona/New Mexico Plateau < 10.1 Cold Deserts < 10 North American Deserts (Griffith, 2006).
USGS:
Colorado Plateau Province (Navajo and Datil Section) Southern Rocky Mountains Basin and Range (Mexican Highland and Sacramento Section)
Ecological site concept
The 36XB ecological site was drafted from the existing R036XB006NM – Loamy range site MLRA 36XB (NRCS, 2003). This site occurs on mesas, plateaus, fan remnant, terraces, dipslopes on cuestas, and broad upland valley sides. The typical surface soil textures are from loam, gravelly loam, loamy fine sand, fine sandy loam, sandy loam, silt loam or clay loam. It has an aridic ustic/ustic arid moisture regime and mesic temperature regime. The effective precipitation ranges from 10 to 16 inches.
Gravelly Slopes - Slopes are 3-25%; Soils are skeletal and deep. Soil surface textures are gravelly to very gravelly loam or cobbly loam with subsoil that are loams to clay loam. Landforms are rolling hills, divides, and ridges.
Pinyon-Juniper/Skunkbush Sumac - Slopes are 1-65%; Soils are moderately deep to deep and skeletal and non-skeletal. Surface texture of gravelly to very gravelly sandy loam, very gravelly loam, loam, para-gravelly-ashy loamy coarse sand, and extremely cobbly coarse sandy loam with a sandy subsoil. Landform is mesas, hills, fan piedmonts, valley sides, plateaus, mountain slopes, structural benches, breaks and ridges.
Clayey - Slopes are 0-15%; Soils are moderately deep to deep; soil surface loam, clay loam, silty clay loam, and silty clay over clayey subsoil with textures of clay loam, clay to silty clay loam or silty clay. Landforms are stream terraces, valley floors, fan remnants, alluvial fans, dipslopes on cuestas, mesas, hills, and valley floors.
Malpais - Slopes 1-15%; soils are very shallow to shallow and skeletal and not skeletal; soil surface are loam, stony to very stony loam, very cobbly loam, fine sandy loam, very cobbly fine sandy loam, stony silt loam, stony silty clay loam, and cobbly silty clay loam; Parent materials are basalt influences but can have sometimes influence from sandstone and/or shale. Landforms nearly level to gently sloping mesas, lava plateaus, lava flows, lava flows on valley floors, and ridges
Meadow - Water table 28-72” in depth; slopes 1-5%; soils are deep, Surface textures are silty clay loam, and clay loam with a subsoil of stratified loams, silt loams, silty clay loams, clay loams, very gravelly sand and gravelly sand. Landform is nearly level to gently sloping floodplains.
Salt Meadow - Water table 36-72” in depth; slopes are 1-5%; soils are deep, Surface textures are loam, fine sandy loam, clay loam, silty clay loam with a subsoil of clay or clay loam. Landform is nearly level to gently sloping floodplains. This site is dependent on sub-irrigation and overflow for its moist condition. This site is affected by sodium.
Salty Bottomland – Water table 42-72” in depth; soils are deep, high in sodium, soils are gravelly to skeletal (15-35% rock fragments). Surface textures are loam, fine sandy loam, clay loam and silty clay loam with a subsoil of clay or clay loam. Landform is floodplain.
Sandy - Slopes are 1-15%; soils are deep to very deep; Surface textures are loamy sand, gravelly loamy sand, loamy fine sand, fine sandy loam and sandy loam with sandy subsoil. Landforms are nearly level to gently sloping landscapes on dunes, fan remnant and alluvial fans.
Sandy Savanna (Formerly Sand Plains) - Slopes are 1-25%; soils are deep; Surface textures are loamy sand, loamy fine sand, and sandy loam with sandy subsoil. Landforms are plateaus, mesas, upland plains.
Swale - This site is enhanced by runoff during periods of high runoff (intermittent). The water table depth is greater than 6 ft. Soils are deep to very deep soils that have surface textures of loams, silt loams to clays with loamy subsoil. Landforms are broad valley bottoms, floodplains, and in depressions.
Stony Loam - Slopes 0-15%; soils are deep to very deep and skeletal and non-skeletal; Surface soil textures are cobbly loam, or loam. Subsoils are loamy. Landforms are nearly level alluvial fans, stream terraces, plateaus, mesas and volcanic cones.
Gravelly Hills - Slopes are (10-65%); Soils are very deep and skeletal and non-skeletal. Surface texture of gravelly to very gravelly fine sandy loam, very gravelly sandy loam, very cobbly loam, or gravelly loam with a sandy subsoil. Landforms are escarpments, fan piedmonts, mesas, hills, ridges and knolls.
Pinyon Upland (Formerly South of Gallup 13-16”)- Soils are very shallow to shallow and non-skeletal; soil surface is loam, channery loam or clay loam. Landforms are broad mesas, cuestas, and hills interspersed with numerous deep canyons and dry washes.
Pinyon-Juniper-Apache Plume - Slopes are 1-35%; Soils are moderately deep to very deep and can be skeletal/non-skeletal. Soil surface textures are gravelly to extremely loam, loam, very gravelly clay loam, very gravelly to extremely gravelly coarse sandy loam, extremely cobbly fine sandy loam, extremely gravelly sandy clay loam, fine sandy loam, very gravelly fine sandy loam, sandy loam, gravelly sandy loam, and ashy loamy coarse sand with subsoil that are loamy. Landforms are escarpments, fan remnants, mesas, hills, cuestas, benches, fan piedmonts, valley sides, eroded fan remnants, and mountain slopes.
Clayey - Slopes are 0-15%; Soils are moderately deep to deep; soil surface loam, clay loam, silty clay loam, and silty clay over clayey subsoil with textures of clay loam, clay to silty clay loam or silty clay. Landforms are stream terraces, valley floors, fan remnants, alluvial fans, dipslopes on cuestas, mesas, hills, and valley floors.
Sandy - Slopes are 1-15%; soils are deep to very deep; Surface textures are loamy sand, gravelly loamy sand, loamy fine sand, fine sandy loam and sandy loam with sandy subsoil. Landforms are nearly level to gently sloping landscapes on dunes, fan remnant and alluvial fans.
This site occurs on mesas, plateaus, fan remnant, terraces, dipslopes on cuestas, and broad upland valley sides. It usually is level to nearly level but slopes may range up to 15 percent. Elevation ranges from 6,400 to 7,800 feet above sea level.
Table 2. Representative physiographic features
Landforms
(1) Fan remnant (2) Mesa (3) Alluvial fan
Flooding frequency
None
Ponding frequency
None
Elevation
6,400–7,800 ft
Slope
1–15%
Aspect
E, S, W
Climatic features
This site has a semi-arid continental climate. There are distinct seasonal temperature variations. Mean annual precipitation varies from 10 to 16 inches. The overall climate is characterized by cold dry winters in which winter moisture is less than summer. Wide yearly and seasonal fluctuations are common for this climatic zone which can range from 5 to 25 inches. Of this, approximately 25-35% falls as snow, and 65-75% falls as rain between April 1 and November 1. The growing season is April through September. As much as half or more of the annual precipitation can be expected to come during the period of July through September. August is typically the wettest month of the year. The driest period is usually from November to April; and February is normally the driest month. During July, August, and September, 4 to 6 inches of precipitation influence the presence and production of warm-season plants. Fall and spring moisture is conducive to the growth of cool-season herbaceous plants and maximum shrub growth. Growth usually begins in March and ends with plant maturity and seed dissemination when the moisture deficiency and warmer temperatures occur in early June. There is also a period of growth in the fall. Summer precipitation is characterized by brief thunderstorms, normally occurring in the afternoon and evening. Winter moisture usually occurs as snow, which seldom lies on the ground for more than a few days. The average annual total snowfall is 29.1 inches. The snow depth usually ranges from 0 to 1 inches during the winter months. The highest snowfall record is 57.1 inches during the 1993-1994 winter. The frost- free period typically ranges from 110 to 145 days and the freeze free period is from 140 to 170 days. The last spring freeze is the middle of April to the first week of May. The first fall freeze is the middle of October to the first week of November. Mean daily annual air temperature is about 29ºF to 69ºF, averaging about 37ºF for the winter and 67ºF in the summer. The coldest winter temperature recorded was -20ºF on January 6, 1971 and the warmest winter temperature recorded was 70ºF on February 28, 1965. The coldest summer temperature recorded was 26ºF on June 1, 1980. The hottest day on record is 100ºF on July 9, 2003 and June 21, 1968. Data taken from Western Regional Climate Center (2017) for El Rito, New Mexico Climate Station.
Table 3. Representative climatic features
Frost-free period (average)
126 days
Freeze-free period (average)
145 days
Precipitation total (average)
13 in
Bar
Line
Figure 2. Monthly precipitation range
Bar
Line
Figure 3. Monthly average minimum and maximum temperature
Figure 4. Annual precipitation pattern
Figure 5. Annual average temperature pattern
Climate stations used
(1) COCHITI DAM [USC00291982], Pena Blanca, NM
(2) SANTA FE 2 [USC00298085], Santa Fe, NM
(3) ABIQUIU DAM [USC00290041], Gallina, NM
(4) CUBA [USC00292241], Cuba, NM
(5) LYBROOK [USC00295290], Dulce, NM
(6) EL RITO [USC00292820], El Rito, NM
(7) NAVAJO DAM [USC00296061], Navajo Dam, NM
Influencing water features
This site is not influenced by water from a wetland or stream.
Soil features
The soils generally are deep and well drained. The surface layers range from loam, gravelly loam, loamy fine sand, fine sandy loam, sandy loam, silt loam and clay loam. Surface texture range in clay percent from 12 to 25% clay. Subsoils range from loam to clay loam. The clay percentage at 20 inches in depth ranges from 20 to 35%. The parent material consists of fan alluvium derived from sandstone and/or shale; alluvium derived from igneous and metamorphic rock; alluvium derived from sandstone and shale; alluvium derived from sandstone and shale and/or eolian deposits derived from sandstone and shale; eolian deposits over slope alluvium derived from sandstone, shale or igneous rock; slope alluvium derived from sandstone and shale; eolian deposits over fan and slope alluvium derived from sandstone and shale or mixed alluvium and/or residuum weathered from igneous and sedimentary rock.
This site is found in NM618, NM606, NM656, NM600, NM678, NM698, NM650, NM672, NM670, NM717, and NM692 soil surveys. This ecological site has been correlated to the following soils with the listed particle control sections:
Fine-Loamy:
Buckle, Fernando, Gapmesa, Hernandez, Kim, Manzano, Mentmore, Nalivag, Oelop, Orlie, Parkelei, Penistaja, Pinitos, Prewitt, Teromote, and Vosburg
Fine-Silty:
Chinlini, Chita, Elpedro, and Las Lucas
Table 4. Representative soil features
Parent material
(1) Alluvium–sandstone and shale (2) Eolian deposits–sandstone and shale (3) Slope alluvium–sandstone and shale
Surface texture
(1) Loam
(2) Silt loam
(3) Clay loam
Family particle size
(1) Loamy
Drainage class
Well drained
Permeability class
Moderately slow to moderate
Soil depth
40–72 in
Surface fragment cover <=3"
15%
Surface fragment cover >3"
2%
Available water capacity (0-40in)
5–8 in
Calcium carbonate equivalent (0-40in)
10%
Electrical conductivity (0-40in)
2 mmhos/cm
Sodium adsorption ratio (0-40in)
2
Soil reaction (1:1 water) (0-40in)
6.6–8.4
Subsurface fragment volume <=3" (Depth not specified)
20%
Subsurface fragment volume >3" (Depth not specified)
15%
Ecological dynamics
MLRA 36 occurs on the higher elevation portion of the Colorado Plateau. The Colorado Plateau is a physiographic province which exists throughout eastern Utah, western Colorado, western New Mexico and northern Arizona. It is characterized by uplifted plateaus, canyons and eroded features. The Colorado Plateau lies south of the Uintah Mountains, north of the Mogollon transition area, west of the Rocky Mountains, and east of the central Utah highlands. The higher elevation portion of the Colorado Plateau which is represented by MLRA 36 is characterize by broken topography, and lack of perennial water sources. This area has a long history of past prehistoric human use for years. MLRA 36 shows archaeological evidence indicating that pinyon-juniper woodlands where modified by prehistoric humans and not pristine and thus where altered at the time of European settlement (Cartledge & Propper, 1993). This area also included natural influences of herbivory, fire, and climate. This area rarely served as habitat for large herds of native herbivores or large frequent historic fires due to the broken topography. This site is extremely variable and plant community composition will vary with the water fluctuations on this site.
The lower part MLRA 36 developed under climatic conditions that include hot, dry summers with summer rains showers and little to no snow with the mild winter temperatures. This area has climatic fluctuations and prolonged droughts are common occurrences. Between an above average year and a drought year. Forbs are the most dynamic component of this community and can vary up to 4 fold (Passey et.al. 1982). The precipitation and climate of MLRA 36 are conducive to producing Pinyon/juniper, and sagebrush complexes with high productive sites in the bottoms of the canyons. Predominant species on the Colorado Plateau are Wyoming big sagebrush (Artemisia tridentata var. wyomingensis), mountain big sagebrush (A. tridentata var. vaseyana), and black sagebrush (A. nova), basin big sagebrush (A. tridentata var. tridentata), Utah juniper (Juniperus utahensis), one-seed juniper (Juniperus monosperma), and two-needle pinyon (Pinus edulis). One-seed juniper has the capability to discontinue active growth when moisture is limited but can resume growth when moisture availability improves. This growth pattern may represent an important adaptation allowing them to survive on very arid sites
The ability for an ecological site to carry fire depends primarily on the present fuel load and plant moisture content—sites with small fuel loads will burn more slowly and less intensely than sites with large fuel loads. Fire is an important aspect of grass dominated ecological sites. LANDFIRE modelled southwest desert grasslands fire return interval as 10 to 833 years (USFS, 2012). Historically, fires were of mixed severity, and various patchy sizes which formed mosaics. Fires varied in intensity and frequency depending on the site’s productivity. So, the variability in severity, patchy sizes, intensity and frequency has led to large variabilities in the fire regimes and fire return intervals.
Shrub vegetation is able to reestablish from seed dispersal from the adjacent non burned shrub stands; however the process is relatively slow. Fire also decreases the extent of One-seed juniper/pinyon pine invasions, which allows the historic plant community to maintain integrity. When the plant community is burned shrubs decrease, while perennial and annual grasses increase. The perennial shrubs associated with this site are able to recover at a faster rate than the invading trees. When the site is degraded by the presence of invasive annuals, the fire return interval is shortened due to increased fuels. The shortened fire return interval is often sufficient to suppress the native plant community.
Variability in climate, soils, aspect and complex biological processes will cause the plant communities to differ. These factors contributing to annual production variability include wildlife use, drought, and insects. Factors contributing to special variability include soil texture, depth, rock fragments, slope, aspect, and micro-topography. The species lists are representative and not a complete list of all occurring or potentially occurring species on this site. The species lists are not intended to cover the full range of conditions, species and responses of the site. The State & Transition model depicted for this site is based on available research, field observations and interpretations by experts and could change as knowledge increases. As more data is collected, some of these plant communities may be revised or removed, and new ones may be added. The following diagram does not necessarily depict all the transitions and states that this site may exhibit, but it does show some of the most common plant communities.
The reference state represents the plant communities and ecological dynamics of the Loamy site. This state includes the biotic communities that become established on the ecological site under the natural disturbance regime prior to pre-European settlement. The main pathways on this site are fire and drought. This is a grassland site with scattered shrubs throughout the site. Grasses are dominant and cover is fairly uniform with few large bare areas present. Western wheatgrass, Indian ricegrass, needle-and-thread and New Mexico feathergrass are the dominant grass species. Dropseeds, galleta, squirreltail, and blue grama can also occur in significant amounts. Shrubs typical of this site may include big sagebrush, four-wing saltbush, winterfat, and spineless horsebrush. Annual forbs occur in high abundance in spring and summer month during years of above-average precipitation. Typically, species such as western wheatgrass, Indian ricegrass, New Mexico feathergrass, four-wing saltbush, and winterfat decrease in response to a combination of heavy grazing and drought.
Reference state is self-sustaining and resistant to change due to high resistance to natural disturbances and high resilience following natural disturbances. When natural disturbances occur, the rate of recovery is variable due to disturbance intensity. Once invasive plants establish, return to the reference state may not be possible. Continuous, yearlong grazing, which allows repetitive grazing of the desirable species, eventually leads to a decrease in these species from the plant community. Such deterioration is indicated by a decrease in Indian ricegrass, needlegrasses, winterfat, and four-wing saltbush. Species that increase include blue grama, galleta, threeawns, sagebrush, and rubber rabbitbrush. One-seed juniper may invade this site from adjacent sites if the vigor of the herbaceous species decreases significantly.
Community 1.1 Perennial Grassland
This is a grassland site with scattered shrubs throughout the site. Grasses are dominant and cover is fairly uniform with few large bare areas present. Western wheatgrass, Indian ricegrass, needle-and-thread and New Mexico feathergrass are the dominant grass species. Forbs are conspicuous when in bloom but otherwise comprise a minor component. Sagebrush, four-wing saltbush and winterfat are the dominant shrubs with rubber rabbitbrush and spineless horsebrush occurring in lesser amounts. Few, if any, trees occur on this community phase.
Other species include: sideoats grama, sand dropseed, pine dropseed, mat muhly, pingue, wooly plaintain, globemallow spp., prairie coneflower, oneseed juniper, pinyon pine, pale wolfberry (pale desert-thorn), broom snakeweed, yucca spp., cholla cactus and antelope bitterbrush.
Figure 8. 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
438
621
803
Shrub/Vine
114
161
209
Forb
48
68
88
Total
600
850
1100
Table 6. Soil surface cover
Tree basal cover
0%
Shrub/vine/liana basal cover
5-15%
Grass/grasslike basal cover
15-25%
Forb basal cover
1-5%
Non-vascular plants
0%
Biological crusts
0%
Litter
15-25%
Surface fragments >0.25" and <=3"
0-5%
Surface fragments >3"
0%
Bedrock
0%
Water
0%
Bare ground
40-60%
Figure 9. Plant community growth curve (percent production by month). NM0006, R036XB006NM Loamy HCPC. R036XB006NM Loamy HCPC Grassland with scattered shrubs and a minor component of forbs..
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
10
10
25
30
12
5
0
0
Community 1.2 Warm Season Grass
Blue grama is both drought and grazing resistant and may persist, but in a less productive, less vigorous form. This is a plant community phase that is dominated by blue grama with galleta and threeawns as subdominants may result. Western wheatgrass, blue grama, galleta will have increased while needle-and-thread, squirreltail and Indian ricegrass have decreased in abundance. Scattered shrubs, such as sagebrush, one-seed juniper and maybe two-needle pinyon might have encroached. Two-needle pinyon and One-seed juniper are natural invaders if stands are found adjacent to this site. Trees left uncontrolled can form dense stands and eventually dominate the site. Nonnative invasive species, such as cheatgrass may be present but in insignificant amounts. Bare ground is most common in this community phase.
Community 1.3 Perennial Shrub
This community consists mature shrubs with sparse understory. Scattered one-seed juniper and maybe two-needle pinyon might be present. Bare ground is most common in this community phase. Improper grazing use can aid the establishment of pinyon and juniper seedlings through reduced competition, exposure of mineral soil, and reduction of fuel to carry fires. This combined with increasing control of fires has caused large portions of the site to be taken over by pinyon and juniper since the coming of livestock. Two-needle pinyon and one-seed juniper are natural invaders if stands are found adjacent to this site. Trees left uncontrolled can form dense stands and eventually dominate the site. The loss of herbaceous cover due to overgrazing, fire suppression, and consequent surface soil horizon loss from water or wind facilitate the transition Pinyon-juniper state.
Pathway 1.1A Community 1.1 to 1.2
This pathway favors shrub establishment. Events that cause this pathway are cause by time without disturbance (i.e. lack of fire), wet winter cycles, drought and improper grazing.
Pathway 1.2A Community 1.2 to 1.1
This transition is caused by naturally occurring fires and/or drought. With a mature shrub community, this pathway can be caused by high intensity fire that burns hot enough to remove the mature shrubs. Low-intensity fire after the shrubs has had a chance to set seed, improper grazing and or browsing by native ungulates, and possible stem-root pathogens will revert a young shrubs community to a grassland with the potential to become a shrub-grass community once again.
Pathway 1.2B Community 1.2 to 1.3
This transition is from the native shrub and perennial warm and cool season grass state, to a state that is dominated by mature shrubs. This pathway happens when fire does not occur within the historical fire regime interval for the site. Improper continuous grazing of perennial grasses will speed up this pathway. This will lead to an old decadent stand of shrubs with little to no understory. This allows the possibility of one-seed juniper and/or two-needle pinyon to become established on the site.
Pathway 1.3B Community 1.3 to 1.1
Pathways can be one or more of the following: brush treatments, seeding, insect herbivory/pathogen, proper grazing, drought, and fire. Insect herbivory and/or root and stem pathogen die-off will thin the stands and allow perennial plants to establish if it is properly grazed.
Pathway 1.3A Community 1.3 to 1.2
This pathway is caused by naturally occurring fires, drought and/or insect herbivory removes the shrubs and possible trees if they have encroached on this site. It reverts the system back to a grassland phase. Vegetation treatments can mimic this natural pathway.
State 2 Pinyon-Juniper
This state is characterized by a loss of grass cover and an increase in pinyon and juniper. Shrub species such as rubber rabbitbrush, spineless horsebrush, big sagebrush, and Bigelow sagebrush may also increase in representation. It is thought that pinyon and juniper, with an understory of mostly perennial grasses, may dominate the site in the longtime absence of fire, but lightning fires following warm dry early summer weather are a natural feature of the region. This could have maintained much of the site in a grassland cover, as reported by many early settlers except for occasional trees and isolated patches. Such vegetation is the basis for the potential described here. Without fire, simulated clearing methods may be necessary to maintain it (Miller and Tausch 2002). This state typically occurs when there is a long time span between fires. The transition to this state also has a reduction in fine fuels plays a part in increasing the fire return intervals once the site has transition to this pinyon-juniper state. Thus, state can persist for long time periods until the conditions needed for a fire occur or vegetation treatments are done to move the community to a different state.
Community 2.1 Pinyon-Juniper Encroached
It is dominated by a dense closed canopy of one-seed juniper and pinyon. They will be with a sparse understory of shrubs with little to no grass or forbs. Blue grama is typically the dominant grass. Galleta and dropseeds may also make up a significant proportion of the grass community. Evidence of erosion such as pedestalling of plants, elongated water flow patterns, litter dams, and rills may be common. Also, Invasive annuals grasses and forbs will be present in the understory.
Community 2.2 Pinyon-Juniper Eroded
This state has an overstory of one-seed juniper and/or two-needle pinyon with a very little understory of shrubs and few perennial grasses and forbs. There is very little herbaceous or other plant growth on this site. Grass cover is extremely sparse usually restricted to a few scattered patches of blue grama or widely scattered individual bunchgrasses. Large areas of bareground are present. The production and infiltration is low. Rills and small gullies are common. Litter is concentrated beneath pinyon-juniper canopies. Erosion is high, and the associated watersheds will become less stable and have more runoff.
State 3 Seeded
This state results from seeding introduced perennial grasses (i.e. crested wheatgrass and Russian wildrye). Native perennial grasses, forbs and shrubs may be included in the seed mix. This state behave similar community dynamics to the current potential state community. Other vegetation treatments may be necessary to get to this state, they include chaining, mowing, disking, prescribed burning and other techniques which manipulate the plant community. Applying vegetation treatments to plant communities to either the invasive annuals or pinyon-juniper encroachment states to create a seeded state is often the first step in assisted restoration to plant communities an intermediate step to get to the Reference State. The seeded state could persist for long periods of time with proper management. Native grasses and forbs may reestablish over time from nearby seed sources.
Community 3.1 Seeded Grassland
This community is dominated by seeded plants such as crested wheatgrass, Russian wildrye, smooth brome, and intermediate and pubescent wheatgrasses. Shrubs have little to no production in this phase. This site has high production due to the seed grass production. This production typically is higher than the current potential or reference state. This site usually has low species diversity.
Community 3.2 Seeded Grassland and Shrubland
This phase has shrubs co-dominant with the seeded grass.
Community 3.3 Seeded Shrubland
This community consists shrub overstory with sparse understory. Scattered one-seed juniper and maybe two-needle pinyon might have encroached. Two-needle pinyon and one-seed juniper are natural invaders if stands are found adjacent to this site. Trees left uncontrolled can form dense stands and eventually dominate the site. Nonnative invasive species, such as cheatgrass are present but in insignificant amounts. Bare ground is most common in this community phase.
Pathway 3.2A Community 3.2 to 3.3
This pathway is caused by naturally occurring fires, herbivory of shrub, and/or drought that suppresses shrub establishment. These events tend to favor grass establishment. With a mature shrub community, this pathway can be caused by high intensity fire that burns hot enough to remove the shrubs and pinyon-juniper, if it has started to encroach. Low-intensity fire after the shrubs has had a chance to set seed, improper grazing and or browsing by native ungulates, and possible stem-root pathogens will revert a young shrub community back to a grassland with the potential to become a grassland community once again. Vegetation treatments (mechanically, prescribed fire, chemically, etc.) can also be employed to imitate the natural disturbances regime.
Pathway 3.3A Community 3.3 to 3.3
This pathway is caused by naturally occurring fires, vegetation treatments (chemical and mechanical), and/or insect herbivory removes the shrubs and possible trees if they have encroached on this site. It reverts the system back to a grassland phase. Depending on the amount of understory present, grasses and forbs may need to be reseeded to aid reestablishment.
State 4 Invaded
This state is dominated by invasive annual species. Invasive annual species can including cheatgrass, Russian thistle, kochia, halogeton, storksbill geranium, and annual mustards. Generally as ecological conditions deteriorate and perennial vegetation decreases due to disturbance (fire, over grazing, drought, off road vehicle overuse, erosion, etc.) annual forbs and grasses will invade the site. The presence of these species will depend on soil properties and moisture availability; however, these invaders are highly adaptive and can flourish in many locations. Once established, complete removal is difficult but suppression may be possible.
Community 4.1 Shrubs and Annuals
This phase will look like shrub overstory with an invasive annual species understory. Frequently, shrub canopy cover will be dense due to little to none perennial understory being present. Cheatgrass, and other annual introduced species are now present in the understory. With repeated fire, it will then transition to an annual species plant community phase (4.2). This phase is at risk for becoming an annual grass-dominated community.
Community 4.2 Annual Monoculture
This community is characterized by an almost a complete monoculture of cheatgrass and/or other invasive annuals. This community can be long-lasting phase if fires and disturbance continue to be frequent.
Pathway 4.1A Community 4.1 to 4.2
This pathway occurs when frequent fire or drought remove the non-sprouting shrubs such as big sagebrush, and favor the establishment of cheatgrass or other invasive annuals. In a degraded shrub community, cheatgrass will take advantage of the increased interspaces between plants will typically establish in the interspaces. Once annuals get established it creates a fine fuel load which will decrease the fire return interval. With more frequent fires, non-sprouting shrubs can be eliminated from the site and a monocultures of invasive annuals can become established. These monocultures can persist for long time periods. Frequent fires also prevent the re-establishment of non-sprouting shrubs on the site.
Pathway 4.2A Community 4.2 to 4.1
This pathway occurs when there is a longer fire return interval. Longer fire return intervals can be enabled by using fire suppression and fire breaks to allow perennial vegetation to a change to get established. Along with this seeding and/or proper grazing may allow native perennial plants to return to this community. This pathway has very intensive energy inputs.
Transition T1A State 1 to 2
This transition is from the native shrub and perennial warm and cool season grass state, to a state that is dominated by two-needle pinyon and one-seed juniper. Events include time without disturbance, insect herbivory, continuous season long grazing of perennial grasses, drought, and tree invasion. As canopy density increase, bare ground will increase in size and frequency further increasing the fire return interval, accelerating erosion, increasing run-off and further affecting the watershed functionality. Loss of herbaceous cover can also reduce fuel levels beyond the point capable of carrying fire. This transition also favors the establishment of invasive annual species such as cheatgrass.
Transition T1B State 1 to 3
This transition is from a shrub dominated state, to a state that has been seeded with introduced perennial grasses. High energy inputs are needed for this transition. Shrubs and/or trees will need to be removed with vegetation treatment techniques (I.e. chemical, mechanical, or fire) and introduced species that are adapted to the area and adapted to management needs have been seeded and become established.
Restoration pathway R2A State 2 to 1
Pathways can be one or more of the following: brush treatments, seeding, insect herbivory/pathogen, proper grazing, drought, and/or fire. This pathway requires lots of energy input into the system. Prescribed grazing will help ensure adequate deferment period or rest following brush control and/or seeding, and will assist in the establishment and maintenance of grass cover. Erosion control would be necessary to prevent further nutrient and soil loss. The addition of organic matter or other soil amendments may be needed to restore soil fertility and facilitate grass recovery.
Transition T2B State 2 to 3
Seeding of introduced/native species (grasses and forbs) is the pathway to state 3. Also, trees are usually removed by mechanical or chemical treatments. This transition requires energy input into the system.
Transition T2A State 2 to 4
This transition is from a two needle pinyon and one-seed juniper state, to a state that is dominated by invasive species. Events would include establishment of invasive species, fire, and other methods of tree removal with an understory that is dominated by invasive annual species (i.e. cheatgrass).
Restoration pathway R3A State 3 to 1
This return path could possible occur as a result of long time frames without disturbance. Native plants from adjacent site would slow establish in the seeded state. Proper grazing from livestock and wildlife which would favor the establishment of native plants. Removal of the one-seed juniper and pinyon as they encroach would also be necessary
Transition T3B State 3 to 2
This transition is from the shrub-seeded grass state to a state that is dominated by two-needle pinyon and one-seed juniper. Events include, fire suppression, time without disturbance, insect herbivory, continuous season long grazing of perennial grasses, and tree invasion. As canopy density increase, bare ground will increase further increasing the fire return interval, accelerating erosion, increasing run-off and further affecting the watershed functionality. This transition also favors the establishment of invasive annual species such as cheatgrass.
Transition T3A State 3 to 4
This transition is from a seeded state, to a state that is dominated by invasive species. Events include increased of invasive species, shortened fire return interval, and long term drought. Improper continuous season long grazing of perennial grasses can reduce the time needed for this pathway.
Transition T4A State 4 to 2
This transition requires fire return intervals to length and fire suppression may be necessary to interrupted the shorten fire return intervals that occur when cheatgrass and other annuals invade. Juniper will encroach onto the site with time and lack of fire. Seeding may be necessary to establish perennial plants. This could require significant energy inputs to make this transition happen.
Restoration pathway R4A State 4 to 3
Invasive annuals will need to be treated and dominance suppress enough to allow desired seeded species the ability to complete so that they can become established. Seeding of introduced species is the pathway to state 3. This transition will be difficult and require substantial inputs and management of the site. It may not be practical on a large scale. Research is needed for species adapted to compete with annual invasive plants, and seeding techniques to add with successful transition from the invasive annual state.
Additional community tables
Table 7. Community 1.1 plant community composition
The runoff curve numbers are determined by field investigations using hydrologic cover
conditions and hydrologic soil groups.
Hydrologic Interpretations:
Soil Series-----Hydrologic Group
Oelop C
Buckle B
Fernando B
Orlie C
Pinitos B
Parkelei B
Vosburg B
Recreational uses
This site, though not noted for its outstanding natural beauty, is well suited for horseback riding, camping, and hunting.
Wood products
This site produces no significant wood products in its potential plant community.
Other products
Grazing:
Approximately 90 percent of the vegetation produced on this site is suitable for grazing or browsing by domestic livestock and wildlife. Grazing distribution is generally not a problem if adequate watering is provided. are provided. Continuous grazing, which allows repetitive grazing of the desirable plant species, eventually can lead to reduced vigor and eventual decrease in production and composition of the desirable species. Such deterioration is indicated by a decrease in
western wheatgrass, muttongrass, and other cool-season grasses as well as fourwing saltbush and winterfat. Species that increase include blue grama, galleta, ring muhly, mat muhly, big sagebrush, rabbitbrush, and broom snakeweed. Juniper and pinyon may invade from adjacent sites.
A planned grazing system with periodic grazing and rests is best to maintain the desired composition and high productivity.
In addition to domestic livestock, this site is used by deer, elk, pronghorn antelope, small mammals, and birds.
Other information
Guide to Suggested Initial Stocking Rate Acres per Animal Unit Month
Cartledge, T. R., and J. G. Propper. 1993. Pinon-Juniper Ecosystems through Time: Information and Insights from the Past. In Gen. Tech. RM-236 - Managing Pinon-Juniper Ecosystems for Sustainability and Social Needs.
Cleland, D.T.; Freeouf, J.A.; Keys, J.E., Jr.; Nowacki, G.J.; Carpenter, C; McNab, W.H. 2007. Ecological Subregions: Sections and Subsections of the Conterminous United States.[1:3,500,000], Sloan, A.M., cartog. Gen. Tech. Report WO-76. Washington, DC: U.S. Department of Agriculture, Forest Service.
Griffith, G.E.; Omernik, J.M.; McGraw, M.M.; Jacobi, G.Z.; Canavan, C.M.; Schrader, T.S.; Mercer, D.; Hill, R.; and Moran, B.C., 2006. Ecoregions of New Mexico (color poster with map, descriptive text, summary tables, and photographs): Reston, Virginia, U.S. Geological Survey (map scale 1:1,400,000).
Miller, R. F. and R. J. Tausch. 2002. The role of fire in juniper and pinyon woodlands: a descriptive analysis. Proceedings: The First National Congress on Fire, Ecology, Prevention, and Management. San Diego, CA, Nov. 27 - Dec. 1, 2000. Tall Timbers Research Station,
Tallahassee, FL.
Natural Resources Conservation Service (NRCS). 2003. Ecological Site Description for Loamy R036XB006NM: USDA, Albuquerque. New Mexico.
Passey, H. B., W. K. Hugie, E. W. Williams, and D. E. Ball. 1982. Relationships between soil, plant community, and climate on rangelands of the Intermountain west. USDA, Soil Conservation Service, Tech. Bull. No. 1669.
U.S. Department of Agriculture, Forest Service, Missoula Fire Sciences Laboratory (USFS). 2012. Information from LANDFIRE on fire regimes of southwestern desert grasslands. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Missoula Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us/database/feis/fire_regimes/SW_desert_grass/all.html [2018, January 30].
United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
Don Sylvester Elizabeth Wright John Tunberg Michael Carpinelli Suzanne Mayne Kinney
Approval
Kirt Walstad, 4/01/2025
Acknowledgments
Project Staff:
Suzanne Mayne-Kinney, Ecological Site Specialist, NRCS MLRA, Grand Junction Colorado SSO Chuck Peacock, MLRA Soil Survey Leader, NRCS MLRA Grand Junction Colorado SSO
Alan Stuebe, MLRA Soil Survey Leader, NRCS MLRA Alamosa Colorado SSO
Program Support:
Brenda Simpson, NRCS NM State Rangeland Management Specialist, Albuquerque, NM
Scott Woodhall, NRCS MLRA Ecological Site Specialist-QA Phoenix, AZ
Eva Muller, Regional Director, Rocky Mountain Regional Soil Survey Office, Bozeman, MT
Rick Strait, NM State Soil Scientist, Albuquerque, NM
Steve Kadas, CO State Resource Conservationist, Albuquerque, NM
--Site Development and Testing Plan--:
Future work to validate and further refine the information in this Provisional Ecological Site Description is necessary. This will include field activities to collect low-, medium-, and high-intensity sampling, soil correlations, and analysis of that data.
Additional information and data is required to refine the Plant Production and Annual Production tables for this ecological site. The extent of MLRA 36 must be further investigated.
Field testing of the information contained in this Provisional ESD is required. As this ESD is moved to the Approved ESD level, reviews from the technical team, quality control, quality assurance, and peers will be conducted.
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)
Doug Whisenhunt
Contact for lead author
Date
09/26/2023
Approved by
Kirt Walstad
Approval date
Composition (Indicators 10 and 12) based on
Annual Production
Indicators
Number and extent of rills:
None to very rare. Some minor rilling may be found on slopes greater than five percent after fire and a severe storm event. Rills are widely spaced and short.
Presence of water flow patterns:
None to very rare. Following intense rainfall events, there may be a few and short (3-6 feet) water flow patterns which are not connected. On slopes greater than five percent, following fire and rain, flow patterns may extend up to 10 feet, but still be widely spaced.
Number and height of erosional pedestals or terracettes:
Very minor. Plant or rock pedestals and terracettes are almost always in water flow patterns. Some build up of soil occurs under sagebrush due to settling of wind-blown material.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are
not bare ground):
Bare ground ranges from 40 t0 60%, with bare patches ranging from 6-10 inches in diameter.
Number of gullies and erosion associated with gullies:
No gullies are actively eroding. Some stable gullies may be present in landscape settings where off-site drainage exists, caused by natural events such as fire followed by an intensive rainfall event. Gullies are shallow with blunted edges and are re-stabilizing.
Extent of wind scoured, blowouts and/or depositional areas:
Wind erosion and deposition is negligible.
Amount of litter movement (describe size and distance expected to travel):
Litter is small and generally will not move over 3 feet, this following intense rainfall.
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range
of values):
The soil stability rating ranges from 4-6.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
The most common surface soil structure is platy. The A Horizon color often ranges from 10YR 5/3 to 10YR 4/3. The soil surface texture is commonly silt loam and the A horizon thickness ranges from 0 to 4 inches.
Effect of community phase composition (relative proportion of different functional groups) and spatial
distribution on infiltration and runoff:
The composition/distribution of cool -season grasses, shrubs, and forbs slows the overland flow and reduces raindrop impact while improving infiltration. This facilitates infiltration and minimizes runoff.
Presence and thickness of compaction layer (usually none; describe soil profile features which may be
mistaken for compaction on this site):
Usually 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:
Cool-season grasses
Sub-dominant:
shrubs<forbs
Other:
Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or
decadence):
There is minimal plant mortality and decadence.
Average percent litter cover (%) and depth ( in):
Litter cover ranges from 15 to 25 percent, with an average depth of .25 inches.
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
The total production on this site ranges from 600 to 1100 pounds per acre.
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:
Tree species such as pinon and juniper can invade this site causing decreased hydrologic function.
Perennial plant reproductive capability:
During years with average to above average growing conditions, all perennial plants should have the ability in most years to produce see, tillers, or sprouts. Natural events that cause limitations to plant reproductive capability include: wildfire, drought, natural disease, inter-species competition, insect cycles, and wildlife activity.
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.
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