Search

Search for a Major Land Resource Area or ecological site by name and/or ID.

Natural Resources
Conservation Service

Ecological site R119XY075OK

Sandy Savannah

Accessed: 11/21/2024

Home / Esd catalog / MLRA 119X / Ecological site R119XY075OK

USC

Metric

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.

Click to explore map

Figure 1. Mapped extent

Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.

MLRA notes

Major Land Resource Area (MLRA): 119X–Ouachita Mountains

This ecological site is found in MLRA 119: Ouachita Mountains.
This area is in the Ouachita Mountains Section of the Ouachita Province of the Interior Highlands. The steep mountains are underlain by folded and faulted sedimentary and metamorphic rocks. Most of the stream valleys are narrow and have steep gradients, but wide terraces and flood plains border the Ouachita River in western Arkansas. Elevation ranges from 330 feet (100 meters) on the lowest valley floors to 2,625 feet (800 meters) on the highest mountain peaks. Local relief is generally 100 to 200 feet (30 to 60 meters), but it can exceed 980 feet (300 meters).

Classification relationships

Crosstimbers Oak Forest and Woodland

Summary: This system is primarily found within central Texas and Oklahoma, ranging north to southeastern Kansas and east into eastern Oklahoma. It is distinct from the surrounding prairie by the higher density of tree species. The area consists of irregular plains with primarily sandy to loamy Ustalf soils that range from shallow to moderately deep. Rainfall can be moderate, but somewhat erratic, therefore moisture is often limiting during part of the growing season. Short, stunted Quercus stellata and Quercus marilandica characterize and dominate this system. Other species, such as Carya texana, Carya cordiformis, Quercus prinoides, Ulmus crassifolia, and other Quercus spp., can also be present within their respective ranges. The understory often contains species typical of the surrounding prairies, in particular Schizachyrium scoparium. Shrubs such as Rhus spp. may also be present. Drought, grazing, and fire are the primary natural processes that affect this system. Overgrazing and conversion to agriculture, along with fire suppression, have led to the invasion of some areas by problematic brush species such as Juniperus virginiana and Juniperus ashei and Prosopis glandulosa farther south in Texas and Oklahoma. It has also led to decreases in native grass cover allowing for annual grasses and forbs to invade.

Table 1. Dominant plant species

Tree	Not specified
Shrub	Not specified
Herbaceous	Not specified

Download full description

Physiographic features

this site is on 1 to 20 percent slopes of hillsides.

Figure 2. R119XY075OK, Sandy Savannah

Table 2. Representative physiographic features

Landforms	(1) Hill
Flooding frequency	None
Ponding frequency	None
Elevation	91 – 823 m
Slope	1 – 20%
Ponding depth	0 cm
Water table depth	61 – 130 cm
Aspect	SE

Climatic features

Table 3. Representative climatic features

Frost-free period (average)	190 days
Freeze-free period (average)	213 days
Precipitation total (average)	1,346 mm

Bar

Line

Figure 3. Monthly precipitation range

Bar

Line

Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6. Annual average temperature pattern

Climate stations used

(1) BATTIEST [USC00340567], Bethel, OK
(2) MCGEE CREEK DAM [USC00345713], Atoka, OK
(3) WILBURTON 9 ENE [USC00349634], Red Oak, OK

Soil features

The soil series associated with this site are: Shermore, Pirum, Octavia, Clearview. They are Moderately deep, Somewhat poorly drained to Well drained, and Slow to Moderately rapid permeable soils, with very acidic to moderately acidic soil reaction, that formed in Colluvium and residuum from Sandstone and shale.

Table 4. Representative soil features

Parent material	(1) Residuum – sandstone and shale
Surface texture	(1) Very stony clay loam (2) Fine sandy loam
Family particle size	(1) Loamy
Drainage class	Somewhat poorly drained to well drained
Permeability class	Slow to moderately rapid
Soil depth	56 – 99 cm
Surface fragment cover <=3"	0%
Surface fragment cover >3"	0%
Available water capacity (0-101.6cm)	8.13 – 16.51 cm
Calcium carbonate equivalent (0-101.6cm)	0%
Electrical conductivity (0-101.6cm)	0 – 1 mmhos/cm
Sodium adsorption ratio (0-101.6cm)	0
Soil reaction (1:1 water) (0-101.6cm)	5 – 5.9
Subsurface fragment volume <=3" (Depth not specified)	2 – 10%
Subsurface fragment volume >3" (Depth not specified)	0 – 19%

Ecological dynamics

Information contained in this section was adapted from Missouri ESD. The information presented is representative of very complex vegetation communities. Key indicator plants, animals and ecological processes are described to help inform land management decisions. Plant communities will differ across the MLRA because of the naturally occurring variability in weather, soils, and aspect. The Reference Plant Community is not necessarily the management goal. The species lists are representative and are not botanical descriptions of all species occurring, or potentially occurring, on this site. They are not intended to cover every situation or the full range of conditions, species, and responses for the site.

The reference community is characterized as a savanna unit dominated by big bluestem, Indian grass, switch grass, and a wide variety of prairie wildflowers added to the mix of upland drainageway prairie species. Slightly higher areas within or at the edge of the ecological site supported a savanna with scattered post oak.

This ecological site occurs at the base of slopes below upland prairies and woodlands, or as high, isolated terraces surrounded by floodplain forest. The higher position and loamy soil texture created a better drainage situation. Consequently, the site is less wet than adjacent sites.

Fire also played a key role in maintaining this ecological site, likely occurring at least once every 3 years. Fire removed dead plant litter and provided room for a lush growth of prairie vegetation. Fire also controlled woody species. During fire free intervals woody species would have increased in abundance and spread out onto the main prairie. Grazing by native large herbivores, such deer furthermore impacted these sites. Their activities altered the composition, fuel loads and structure of the vegetation, adding to the diversity of structure and composition.

These sites are very productive. Today, Sandy Savannahs are nearly extirpated from the region have been converted to intensive agriculture. Few quality remnants exist. While re-establishing prairie and savanna on converted agriculture sites is beneficial to wildlife, restoration to the reference state from agricultural land is a long term proposition with uncertain outcomes.

A State and Transition Diagram is depicted in Figure 1. Detailed descriptions of each state, transition, plant community, and pathway follow the model. This model is based on available experimental research, field observations, professional consensus, and interpretations. It is likely to change as knowledge increases.

State and transition model

Custom diagram

Standard diagram

Figure 7. R119XY075OK, Sandy Savannah

Figure 8. R119XY075OK, Sandy Savannah

More interactive model formats are also available. View Interactive Models

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Reference

State 1
Reference

This state is native oak savanna dominated by big bluestem and a wide variety of prairie forbs. This state occurs on level to gently sloping soils. Shortleaf pine, and red oak, occurred in small groves or as scattered individuals across the landscape. This state is very rare. Nearly all former reference states have been converted to cool season grassland and intensive agriculture cropland. Small acres remain in a fire suppressed woodland community.

Supporting information

Other references

NatureServe. 2015. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia.
Available http://explorer.natureserve.org. (Accessed: October 27, 2015).

Official Soil Survey, USDA-NRCS: https://soilseries.sc.egov.usda.gov/osdname.asp

Landfire: http://www.landfire.gov 2015 data

United States Department of Agriculture Handbook 296: Land Resource Regions and Major Land Resource Areas
of the United States, the Caribbean, and the Pacific Basin

NASIS database 2016 NASIS Client Version Number 6.4.1 and database model 7.2.5

Acknowledgments

Doug Wallace and Fred Young at Missouri NRCS State office, personal communication and sharing of state and transition models.

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
Approved by
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:

Download reference sheet