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West Gulf Coast Limestone Prairie

EVT 7429West Gulf Coastal Plain Southern Calcareous Prairie

CES203.377GNRHerbGrassland

Summary

This is one of two described calcareous prairie ecological systems which occur within the pine-dominated portions of the Coastal Plain west of the Mississippi River. This type is the more northerly ranging of the two [compare against West Gulf Coastal Plain Southern Calcareous Prairie (CES203.379)]. This system includes natural grassland vegetation and associated wooded vegetation in a relatively small natural region of the Upper West Gulf Coastal Plain of Arkansas and adjacent Oklahoma. Although other calcareous prairies are found west of the Mississippi River, this system represents some of the largest known and highest quality remaining examples. Plant communities in this system occur over relatively deep soils (as well as shallow soils over chalk and limestone) with circumneutral surface soil pH, which is unusual given the predominance of acidic, generally forested soils in the region. In most cases individual prairie openings are small and isolated from one another, but were formerly more extensive prior to European settlement, forming a mosaic of grassland and woodlands under frequent fire regimes. The flora has much in common with other prairie systems of the East Gulf Coastal Plains as well as classic Midwestern prairies.

Source: NatureServe Explorer

Vegetation

Dominant plants in stands of this system vary from example to example; there are several subtypes and associations with variability among these. Typical trees include Quercus stellata, Quercus muehlenbergii, Quercus shumardii, Quercus pagoda, Quercus sinuata, Carya illinoinensis, Carya myristiciformis, Juniperus virginiana var. virginiana, and Maclura pomifera. Some typical shrubs include Forestiera ligustrina, Symphoricarpos orbiculatus, Ilex decidua, and Rhus aromatica. Herbs may include Sorghastrum nutans, Bouteloua curtipendula, Andropogon glomeratus, Leersia virginica, Panicum anceps, Panicum flexile, Sporobolus compositus, Fimbristylis puberula var. puberula, Carex cherokeensis, Carex microdonta, Echinacea pallida, Liatris aspera, Marshallia caespitosa, Silphium integrifolium, Silphium laciniatum, Solidago auriculata, Symphyotrichum lanceolatum, Packera tampicana, Thelesperma filifolium, Nemastylis geminiflora, Dalea purpurea, Lythrum alatum, Allium canadense var. mobilense, and Zigadenus nuttallii.

Source: NatureServe Explorer

Environment

This system is characterized by deep to shallow soils with circumneutral surface soil pH that have developed over Cretaceous-aged calcareous substrates. Soils vary from well-drained to poorly drained clays, silty clays, silty clay loams, and fine sandy loams, and are typically excessively dry in summer exhibiting high shrink-swell potential. Within this general landscape, fine-scale abiotic characteristics in conjunction with ecological processes, frequent fire in particular, supported a mosaic of grasslands and short-statured woodlands comprising the ecological system.

Source: NatureServe Explorer

Dynamics

The composition and structure of this grassland and open woodland ecological system are primarily maintained by edaphic conditions, fire, and climate. Fires less than every four or so years are necessary to maintain the grassland and open woodland states. Under normal weather conditions, eight to ten years without fire will result in a shrub-dominated physiognomy. Continued fire suppression under normal climate conditions will result in a closed-canopy condition. Tight soils provide a barrier to root penetration and limit water availability during dry periods, thereby also inhibiting the establishment and growth of woody plants, but soils alone cannot limit woody growth. Historically, native grazers or browsers also played a role in the maintenance of this system.

Source: NatureServe Explorer

Threats

To date, habitat conversion to tame pasture has resulted in the biggest loss of this ecosystem. What remains is highly threatened by disruption of fire regimes necessary for maintenance of vegetation composition and structure. Intensive land management in conjunction with friable soils has led to severe erosion in some areas, characterized by gullies which can exceed 10.6 m (35 feet) in depth. If changes in regional climate bring about an increase in precipitation, this could lead to an increase in erosion and woody encroachment. Virtually all remaining natural habitat is experiencing degradation due to the spread of tame pasture grasses (D. Zollner pers. comm. 2013).

Source: NatureServe Explorer

Distribution

This system is known only from a relatively small natural region of the Upper West Gulf Coastal Plain of Arkansas and adjacent Oklahoma.

Source: NatureServe Explorer

Ecologically Associated Plant Species

Plant species that characterize this ecosystem type, organized by vegetation stratum. These are species ecologically associated with the ecosystem, not confirmed present in any specific area.

Tree canopy

Carya illinoinensis, Carya myristiciformis, Juniperus virginiana var. virginiana, Maclura pomifera, Quercus muehlenbergii, Quercus pagoda, Quercus shumardii, Quercus sinuata, Quercus stellata

Shrub/sapling (tall & short)

Forestiera ligustrina, Ilex decidua, Rhus aromatica, Symphoricarpos orbiculatus

Herb (field)

Allium canadense var. mobilense, Andropogon glomeratus, Bouteloua curtipendula, Carex cherokeensis, Carex microdonta, Dalea purpurea, Echinacea pallida, Fimbristylis puberula var. puberula, Leersia virginica, Liatris aspera, Lythrum alatum, Marshallia caespitosa, Nemastylis geminiflora, Packera tampicana, Panicum anceps, Panicum flexile, Silphium integrifolium, Silphium laciniatum, Solidago auriculata, Sorghastrum nutans, Sporobolus compositus, Symphyotrichum lanceolatum, Thelesperma filifolium, Toxicoscordion nuttallii

Source: NatureServe Ecological System assessment

Ecologically Associated Animals (3)

Animal species ecologically associated with this ecosystem type based on NatureServe assessment. These are species whose habitat requirements overlap with this ecosystem, not confirmed present in any specific roadless area.

Reptiles (2)

Common Name	Scientific Name	G-Rank
Plateau Spotted Whiptail	Aspidoscelis scalaris	G5
Prairie Kingsnake	Lampropeltis calligaster	G5

Other Invertebrates (1)

Common Name	Scientific Name	G-Rank
American Box Turtle	Terrapene carolina	G5

Source: NatureServe Ecological System assessment

Component Associations (19)

Plant community associations that occur within this ecological system. Associations are the finest level of the U.S. National Vegetation Classification (USNVC) and describe specific, repeating assemblages of plant species. Each association represents a distinct community type that may be found where this ecosystem occurs.

Name	G-Rank
Baccharis halimifolia Ruderal Shrubland	GNA	NatureServe
Cornus drummondii - (Rhus glabra, Prunus spp.) Shrubland	GNR	NatureServe
Crataegus crus-galli - Ilex decidua - Crataegus viridis Shrubland	GNR	NatureServe
Juniperus virginiana / Cynodon dactylon - Schizachyrium scoparium Ruderal Forest	GNA	NatureServe
Juniperus virginiana - Maclura pomifera / Bouteloua curtipendula - Thelesperma filifolium - Packera tampicana Wooded Grassland	G1	NatureServe
Lythrum alatum - Panicum anceps - Symphyotrichum lanceolatum Wet-mesic Blackland Grassland	GH	NatureServe
Quercus falcata - Carya illinoinensis / Silphium integrifolium - Panicum anceps - (Carex cherokeensis) Mesic Wooded Grassland	G1	NatureServe
Quercus muehlenbergii - Quercus sinuata / Rhus aromatica / Liatris aspera - Allium canadense var. mobilense Woodland	G2	NatureServe
Quercus pagoda - (Carya illinoinensis) / Ilex decidua / Carex cherokeensis - Leersia virginica Mesic Blackland Forest	G1	NatureServe
Quercus shumardii - Carya myristiciformis - (Quercus muehlenbergii) / Carex cherokeensis - Sorghastrum nutans Woodland	G1	NatureServe
Quercus sinuata / Solidago auriculata - Zigadenus nuttallii Mixed Herb Dry-mesic Blackland Ravine Woodland	G1	NatureServe
Quercus stellata - Ulmus crassifolia / Ilex decidua / Carex cherokeensis - Schizachyrium scoparium Woodland	G1	NatureServe
Schizachyrium scoparium - Evax prolifera Gravel Glade Grassland	G1	NatureServe
Schizachyrium scoparium - Sorghastrum nutans - Bouteloua curtipendula Dry-mesic Grassland	G2	NatureServe
Schizachyrium scoparium - Sorghastrum nutans - Echinacea pallida - Dalea purpurea Grassland	G2	NatureServe
Schizachyrium scoparium - Sporobolus compositus - Fimbristylis puberula var. puberula Scrub Grassland	G1	NatureServe
Sorghastrum nutans - Andropogon glomeratus - Silphium laciniatum Grassland	G1	NatureServe
Spartina pectinata - Tripsacum dactyloides Grassland	G2	NatureServe
Typha latifolia - Thalia dealbata Marsh	GNR	NatureServe

State Conservation Ranks (2)

Subnational conservation status ranks (S-ranks) assigned by Natural Heritage Programs in each state where this ecosystem occurs. S1 indicates critically imperiled at the state level, S2 imperiled, S3 vulnerable, S4 apparently secure, and S5 secure. An ecosystem may be globally secure but imperiled in specific states at the edge of its range.

State	S-Rank
AR	SNR
OK	SNR

Methodology and Data Sources

Ecosystem classification: Ecosystems are classified using the LANDFIRE 2024 Existing Vegetation Type (EVT) layer, mapped to NatureServe Terrestrial Ecological Systems via a curated crosswalk. Each EVT is linked to the USNVC (U.S. National Vegetation Classification) hierarchy through pixel-level co-occurrence analysis of LANDFIRE EVT and NatureServe IVC Group rasters across all roadless areas.

Vegetation coverage: Coverage percentages and hectares are derived from zonal statistics of the LANDFIRE 2024 EVT raster intersected with roadless area boundaries.

Ecosystem narratives and community species: Sourced from the NatureServe Explorer API, representing professional ecological assessments of vegetation composition, environmental setting, dynamics, threats, and characteristic species assemblages.

IVC hierarchy: The International Vegetation Classification hierarchy is sourced from the USNVC v3.0 Catalog, providing the full classification from Biome through Association levels.

Component associations: Plant community associations listed as components of each NatureServe Ecological System. Association data from the NatureServe Explorer API.

State ranks: Conservation status ranks assigned by NatureServe member programs in each state where the ecosystem occurs.