Physiographic features

These sites are in depressions 3 to 10 feet below the surrounding plain and range in size from a few acres to more than 40 acres. Slopes are nearly level with concave surfaces.

Table 2. Representative physiographic features

Table 3. Representative physiographic features (actual ranges)

Climatic features

Climate is a cold semi-arid steppe (Koppen-Geiger classification BSk). Summers are hot and winters are cold. Temperature extremes are common. Humidity is generally low, evaporation is high, and short-term droughts are common. Average annual wind speed is 12 mph with highest winds in early spring. The prevailing wind direction is south. Summertime brings strong high pressure systems that build into heat domes with highs in the upper 90 to mid-100 degree F range. Evaporation in summer is high and open pan evaporation exceeds 6 feet per year. Early autumn temperatures are mild, with Canadian and Pacific cold fronts bringing cold air in mid-autumn throughout winter. Arctic air can settle in and dominate for several weeks during winter with very cold air in place for 2 to 3 weeks at a time.

Most of the precipitation comes in the form of rain from May through September. Rainfall events often occur as intense showers of relatively short duration. Snowfall average is about 17 inches but is also variable from 8 to 36 inches annually. Long term droughts are likely to occur every 15 to 20 years and may last 4 to 5 years. Mean precipitation is around 21 inches but varies significantly from year to year. Rainfall amounts over the last 100 years have varied from as little as 9 inches to as much as 37 inches. The probability is about 70% that precipitation will fall between 14 to 24 inches. Growing season averages 190 days. Average first frost is around October 22, and the last freeze of the season occurs around April 15.

Table 4. Representative climatic features

Climate stations used

• (1) GATE [USC00343489], Gate, OK

• (2) FOLLETT [USC00413225], Follett, TX

• (3) CANADIAN [USC00411412], Canadian, TX

• (4) BEAVER [USC00340593], Beaver, OK

• (5) MEADE [USC00145171], Meade, KS

• (6) LIPSCOMB [USC00415247], Booker, TX

• (7) COLDWATER [USC00141704], Coldwater, KS

• (8) REYDON 2SSE [USC00347579], Reydon, OK

Influencing water features

This site receives some runoff from surrounding areas. The depression sites are generally closed basins with no outlet, therefore runoff collects and ponds for several days to several months. Infiltration is very slow due to the heavy clay soils.

Wetland description

There is high degree of variability to the water status in individual playas. Some playas exhibit wetland hydrology, have hydric soils, and have predominantly hydrophytic vegetation. The dryer, grass dominated playas often do not exhibit all three of these characteristics.

Soil features

Soils are mapped for each county within the MLRA. Mapunits are representations of the major soil series component(s) and named accordingly. Each Mapunit is spatially represented on a digital soils map as polygons of different shapes and sizes. Within these Mapunits, there are often minor soil series components included. These minor components are soils that occur within a Mapunit polygon but are of small extent (15% or less of the Mapunit area). However, it is difficult to separate these minor soils spatially due to the scale of soil mapping.

Ecological sites are correlated at the component level of the soil survey. Therefore, a single Mapunit may contain multiple Ecological Sites just as it may contain multiple soil components. This is important to understand when investigating soils and Ecological Sites. A soil survey Mapunit may be correlated to a single Ecological Site based on the major component; however, there may be inclusions of areas of additional Ecological Sites which are correlated to the minor components of that particular soil Mapunit.

This group of soils consists of very deep, poorly drained, very slowly permeable soils that formed in clayey lacustrine sediments. These soils occupy closed drainage depressions on stream terraces or stream terrace remnants. They have silty clay or clay surface textures and fine textured subsurface textures that shrink when dried and swell when wet. Slopes range from 0 to 1 percent. Runoff is from surrounding areas collects in the closed basins where this soil resides, and frequent, long duration ponding is typical. Aquic conditions are present in the soil and hydrophytic vegetation may dominate the sites.

Representative soil components for this site include: Rosston. Some older surveys may include the Ness series.

Table 5. Representative soil features

Animal community

A variety of animals utilize the site. Small mammals use the site for food and cover. Frogs and salamanders are found in abundance in wet seasons. Predators such as skunks, coyotes and snakes find food and cover there. Pronghorn will sometime graze around the perimeter of playas. Raptors such as hawks (especially harriers) favor the site as hunting areas. Many species of shorebirds and waterfowl utilize the lakes in wetter seasons. Herons and egrets utilize the wetter playas.

Vegetative cover provided by playas is valuable for species such as waterfowl and a variety of upland birds during the nesting season. Also in the fall and winter the playas provide thermal cover and escape cover.

Plant preference by animal kind:
This rating system provides general guidance as to animal preference for plant species. It also indicates possible competition between kinds of herbivores for various plants. Grazing preference changes from time to time, especially between seasons, and between animal kinds and classes. Grazing preference does not necessarily reflect the ecological status of the plant within the plant community. For wildlife, plant preferences for food and plant suitability for cover are rated.

Preferred (P) – Percentage of plant in animal diet is greater than it occurs on the land
Desirable (D) – Percentage of plant in animal diet is similar to the percentage composition on the land
Undesirable (U) – Percentage of plant in animal diet is less than it occurs on the land
Not Consumed (N) – Plant would not be eaten under normal conditions. It is only consumed when other forages not available.
Toxic (T) – Rare occurrence in diet and, if consumed in any tangible amounts results in death or severe illness in animal

Hydrological functions

The site captures runoff water from surrounding sites. Playas are recharge sites for the Ogallala aquifer.

Recreational uses

Hunting, birdwatching, and nature study areas.

Wood products

None

Other products

None

Other information

None

Inventory data references

Old range site descriptions, condition class worksheets, and soil survey manuscripts were used in the development of this provisional ESD.

USDA, Soil Survey Reports, Soil Series Narratives, USDA-NRCS
Hatch, Gandhi and Brown, Checklist of the Vascular Plants of Texas (Texas A&M, 1990)
Haukos and Smith, Common Flora of the Playa Lakes, Texas Tech University Press, 1997
Correll and Correll, Aquatic and Wetland Plants of the Southwestern United States, 1975

Other references

USDA-NRCS (Formerly Soil Conservation Service) Range Site Descriptions (1960s)
USDA-NRCS (Formerly Soil Conservation Service) Ag Handbook 296 (2006)

Contributors

Colin Walden Range Specialist Stillwater OK
Steven McGowen, MLRA Office Leader, NRCS, Woodward, OK

Approval

Bryan Christensen, 9/12/2023

Acknowledgments

Site Development and Testing Plan
Future work, as described in a Project Plan, to validate the information in this Provisional Ecological Site Description is needed. This will
include field activities to collect low, medium and high intensity sampling, soil correlations, and analysis of that data. Annual field reviews
should be done by soil scientists and vegetation specialists. A final field review, peer review, quality control, and quality assurance reviews
of the ESD will be needed to produce the final document.
Annual reviews of the Project Plan are to be conducted by the Ecological Site Technical Team.