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Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Ecological site concept
Currently there is only a draft of the initial concept for this ecological site. The initial concept for this site places it within the Seasonally Flooded Closed Clay Basins Ecological Site Group. To view the General STM and other information available for this ESG please go to https://edit.jornada.nmsu.edu/catalogs/esg/023X/R023XY912NV
The Wet Clay Basin (023XY023NV) ecological site is the modal site for this group. This site occurs on nearly level enclosed basins. Slopes range from 0 to 4 percent, but slope gradients of 0 to 2 percent are most typical. Elevations are 5500 to 7500 feet. Average annual precipitation is 10 to 14 inches. A seasonally high water table is at or near the surface in most years and the soils are typically ponded through most of the growing season. The soils in this site are deep, dark colored and clayey. When dry, the soils are subject to extensive cracking that damages the root systems of many species of plants. The plant community is dominated by species that can tolerate seasonal ponding: Mat muhly, suncup, sedges, spikerush, and rushes. Silver sagebrush may be present, and povtertyweed (Iva axillaris) may become dominant in dry areas. Production ranges from 0 lb/ac in wet, ponded years, to 1,500 lb/ac in drier years. Normal year annual production is 400 lb/ac.Associated sites
R023XY015NV STONY LOAM 12-14 P.Z.
R023XY016NV SOUTH SLOPE 12-16 P.Z.
R023XY020NV LOAMY 10-12 P.Z.
Similar sites
R023XY003NV CLAY BASIN
A stable plant community; water recedes yearly
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) Muhlenbergia richardsonis
Physiographic features
This site occurs on nearly level enclosed basins, lake plains, and depressions. Slopes range from 0 to 2 percent. Elevations are 5300 to 7200 feet.
Table 2. Representative physiographic features
Landforms (1) Depression
(2) Lake plain
Flooding frequency None Ponding duration Long (7 to 30 days) to very long (more than 30 days) Ponding frequency Occasional to frequent Elevation 5300 – 7200 ft Slope 0 – 2 % Ponding depth 0 – 12 in Water table depth 0 – 84 in Aspect Aspect is not a significant factor Climatic features
The climate associated with this site is semiarid and characterized by cool, moist winters and warm, dry summers. Average annual precipitation is 10 to 14 inches. Mean annual air temperature is 43 to 47 degrees F. The average growing season is about 80 to 100 days.
Nevada’s climate is predominantly arid, with large daily ranges of temperature, infrequent severe storms, heavy snowfall in the higher mountains, and great location variations with elevation. Three basic geographical factors largely influence Nevada’s climate: continentality, latitude, and elevation. Continentality is the most important factor. The strong continental effect is expressed in the form of both dryness and large temperature variations. Nevada lies on the eastern, lee side of the Sierra Nevada Range, a massive mountain barrier that markedly influences the climate of the State. The prevailing winds are from the west, and as the warm moist air from the Pacific Ocean ascend the western slopes of the Sierra Range, the air cools, condensation occurs and most of the moisture falls as precipitation. As the air descends the eastern slope, it is warmed by compression, and very little precipitation occurs. The effects of this mountain barrier are felt not only in the West but throughout the state, with the result that the lowlands of Nevada are largely desert or steppes. The temperature regime is also affected by the blocking of the inland-moving maritime air. Nevada sheltered from maritime winds, has a continental climate with well-developed seasons and the terrain responds quickly to changes in solar heating.
Nevada lies within the mid-latitude belt of prevailing westerly winds which occur most of the year. These winds bring frequent changes in weather during the late fall, winter and spring months, when most of the precipitation occurs. To the south of the mid-latitude westerlies, lies a zone of high pressure in subtropical latitudes, with a center over the Pacific Ocean. In the summer, this high-pressure belt shifts northward over the latitudes of Nevada, blocking storms from the ocean. The resulting weather is mostly clear and dry during the summer and early fall, with scattered thundershowers. The eastern portion of the state receives significant summer thunderstorms generated from monsoonal moisture pushed up from the Gulf of California, known as the North American monsoon. The monsoon system peaks in August and by October the monsoon high over the Western U.S. begins to weaken and the precipitation retreats southward towards the tropics (NOAA 2004).
Average annual precipitation is 16 to over 20 inches. Mean annual air temperature is 41 to 44 degrees F. The average growing season is about 50 to 70 days.
Mean annual precipitaion at the Bear Creek, Nevada SNOTEL station (170501020301) is 37.69 inches.
monthly mean precipitation is:
January 3.84; February 3.75; March 4.38; April 4.9;
May 3.99; June 2.82; July .95; August 1.66;
September 1.22; October 2.12;
November 3.67; December 4.38.Table 3 Representative climatic features
Frost-free period (average) 90 days Freeze-free period (average) Precipitation total (average) 10 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
Figure 3. Annual precipitation pattern
Figure 4 Annual average temperature pattern
">Influencing water features
A seasonally high water table is at or near the surface in most years. The soils are typically ponded through most of the growing season from runoff from adjacent landscapes.
Soil features
The soils associated with this site are very deep, dark colored and clayey. The permeability is very slow, runoff is negligible, and the soils are somewhat poorly to poorly drained. When dry, the soils are subject to extensive cracking that damages the root systems of many species of plants. The dry, cracked condition persists long enough in most years for appreciable surface sloughing to take place, and a hummocky (gilgai) relief is not produced. A seasonally high water table is at or near the surface in most years and the soils are typically ponded through most of the growing season. The soil series associated with this site include: Boulder Lake and Weimer.
Table 4. Representative soil features
Surface texture (1) Silt loam
(2) Silty clay
(3) Clay
Family particle size (1) Clayey
Drainage class Somewhat poorly drained to poorly drained Permeability class Very slow Soil depth 72 – 84 in Surface fragment cover <=3" Not specified Surface fragment cover >3" Not specified Available water capacity
(0-40in)5.9 – 7.2 in Calcium carbonate equivalent
(0-40in)0 – 3 % Electrical conductivity
(0-40in)0 – 4 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 1 Soil reaction (1:1 water)
(0-40in)6.1 – 9.6 Subsurface fragment volume <=3"
(Depth not specified)0 – 1 % Subsurface fragment volume >3"
(Depth not specified)Not specified Ecological dynamics
This is not a stable plant community. This plant community may be completely water covered during the growing season, or it can be a very productive site, dominated by annual forbs, in drier years.
Determinations of ecological condition and a similarity index are not appropriate for this site.
Fire Ecology:
Mat muhly communities are only slightly affected by fire. They are at the highest susceptibility is during late spring and early summer. It takes 5 to 10 years for it to recover to pre fire frequency. Mat muhly is top killed be fire. Fire does not harm mat muhly to any great extent because the rhizome buds are insulated by the soil.State and transition model
Custom diagramStandard diagramMore interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Reference Plant CommunityCommunity 1.1
Reference Plant CommunityThe reference plant community is dominated by annual and perennial forbs, particularly poverty weed. These enclosed basins are generally flooded during much of the growing season. Potential vegetative composition is about 10% grasses, 85% forbs, and up to 5% shrubs. Approximate ground cover (basal and crown) is 0 to over 30 percent. Total foliar cover can exceed 80 percent.
Production is related to the length of growing season remaining as ponding recedes.Figure 5. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Forb 1 340 1275 Grass/Grasslike 0 40 150 Shrub/Vine 0 20 75 Total 1 400 1500 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Primary Perennial Grasses 20–40 mat muhly MURI Muhlenbergia richardsonis 20–40 – 2 Secondary Perennial Grasses/Grasslikes 8–40 sedge CAREX Carex 2–20 – spikerush ELEOC Eleocharis 2–20 – rush JUNCU Juncus 2–20 – 3 Annual Grasses 1–40 Forb4 Perennial 40–128 povertyweed IVAX Iva axillaris 20–40 – evening primrose OENOT Oenothera 8–20 – dock RUMEX Rumex 4–8 – 5 Annual 8–300 Shrub/Vine6 Primary Shrub 1–20 silver sagebrush ARCA13 Artemisia cana 4–8 – Interpretations
Animal community
Livstock Interpretations:
This site can be suitable for livestock grazing. Grazing management should be keyed to perennial grass production. Young mat muhly is readily eaten by livestock. Plants become less palatable as they mature. Mat muhly plants usually grow in scattered patches, so they are seldom sufficiently abundant to be of major importance to livestock. In the northern part of its range, mat muhly is rated as good to very good forage for cattle and horses and fairly good for domestic sheep.
Stocking rates vary over time depending upon season of use, climate variations, site, and previous and current management goals. A safe starting stocking rate is an estimated stocking rate that is fine tuned by the client by adaptive management through the year and from year to year.
Wildlife Interpretations:
The palatability of mat muhly for wildlife species has been rated as fair to poor.Hydrological functions
Runoff is negligible. Permeability is very slow.
Recreational uses
Aesthetic value is derived from the diverse floral and faunal composition and the colorful flowering of wild flowers during early summer. This site offers rewarding opportunities to photographers and for nature study. This site has potential for upland and big game hunting.
Supporting information
Type locality
Location 1: Washoe County, NV Township/Range/Section T35N R18E S12 UTM zone N UTM northing 254972 UTM easting 4534253 Latitude 40° 55′ 21″ Longitude 119° 54′ 35″ General legal description NW 1/4, Garden Lake Flat, Washoe County, Nevada. This site also occurs in Humboldt County, Nevada. Other references
Fire Effects Information System (Online; http://www.fs.fed.us/database/feis/plants/).
USDA-NRCS Plants Database (Online; http://www.plants.usda.gov).
Contributors
BH/SW/GKB
Approval
Kendra Moseley, 4/10/2025
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 09/21/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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