Home/Ecosystems/ Great Plains Mesquite Scrubland

Great Plains Mesquite Scrubland

EVT 7111Western Great Plains Mesquite Shrubland

CES303.668GNRShrubShrubland

Summary

This system is found primarily in the southern portion of the Western Great Plains Division, primarily in Texas, Oklahoma and eastern New Mexico. It is dominated by Prosopis glandulosa with shortgrass species in the understory. Ziziphus obtusifolia and Atriplex canescens can codominate in some examples, as can Opuntia species in heavily grazed areas. Shortgrass species Bouteloua gracilis or Bouteloua dactyloides are typically present. Other grasses may include Aristida purpurea, Bouteloua curtipendula, Bouteloua eriopoda, Bouteloua hirsuta, Muhlenbergia torreyi, Pleuraphis jamesii, Sporobolus airoides, and Sporobolus cryptandrus. Historically this system probably occurred as a natural component on more fertile soils and along drainages, but it has expanded its range into prairie uplands in recent decades. In Texas, in what are considered the natural alluvial setting of this system, other overstory species may include Celtis laevigata var. reticulata, Sapindus saponaria var. drummondii, Populus deltoides, and Salix nigra. In these settings, Prosopis glandulosa is dominant in the shrub layer, but other shrub species encountered include small representatives of the overstory, and Ziziphus obtusifolia, Prunus angustifolia, and Baccharis spp. Herbaceous species present in the understory may include Panicum virgatum, Bothriochloa laguroides ssp. torreyana, Nassella leucotricha, and Schizachyrium scoparium. Non-native species such as Cynodon dactylon, Bromus catharticus, Sorghum halepense, and Bromus arvensis are also commonly present and may be dominant.

Source: NatureServe Explorer

Vegetation

This system is dominated by Prosopis glandulosa with Ziziphus obtusifolia, and Atriplex canescens can codominate. Opuntia spp. can be prevalent in areas in heavily grazed examples of this system. Shortgrass species Bouteloua gracilis or Bouteloua dactyloides (= Buchloe dactyloides) are typically present. In Texas, in what are considered the natural alluvial setting of this system, other overstory species may include Celtis laevigata var. reticulata, Sapindus saponaria var. drummondii, Populus deltoides, and Salix nigra. In these settings, Prosopis glandulosa is dominant in the shrub layer, but other shrub species encountered include small representatives of the overstory, and Ziziphus obtusifolia, Prunus angustifolia, and Baccharis spp. Herbaceous species present in the understory may include Panicum virgatum, Bothriochloa laguroides ssp. torreyana, Nassella leucotricha, and Schizachyrium scoparium. Non-native species such as Cynodon dactylon, Bromus catharticus, Sorghum halepense, and Bromus arvensis are also commonly present and may be dominant.

Source: NatureServe Explorer

Environment

This system occurs naturally on deeper or more fertile soils and along drainages.

Source: NatureServe Explorer

Dynamics

Historically, fire controlled this system and limited the development of woody cover. Likewise, edaphic conditions and topographic factors limited this system to deep alluvial soils in relatively low topographic positions along broad valley floors.

Source: NatureServe Explorer

Distribution

This system is primarily found in the southern portion of the Western Great Plains division, particularly in Texas, Oklahoma and eastern New Mexico.

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

Prosopis glandulosa

Shrub/sapling (tall & short)

Atriplex canescens, Ziziphus obtusifolia

Herb (field)

Aristida purpurea, Bouteloua curtipendula, Bouteloua eriopoda, Bouteloua gracilis, Bouteloua hirsuta, Buchloe dactyloides, Muhlenbergia torreyi, Pleuraphis jamesii, Pleuraphis mutica, Sporobolus airoides, Sporobolus cryptandrus

Source: NatureServe Ecological System assessment

Ecologically Associated Animals (4)

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.

Mammals (2)

Common Name	Scientific Name	G-Rank
Ord's Kangaroo Rat	Dipodomys ordii	G5
Spotted Ground Squirrel	Xerospermophilus spilosoma	G5

Reptiles (2)

Common Name	Scientific Name	G-Rank
Common Lesser Earless Lizard	Holbrookia maculata	G5
Gophersnake	Pituophis catenifer	G5

Source: NatureServe Ecological System assessment

Component Associations (8)

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
Bouteloua dactyloides - Dichanthium annulatum Ruderal Grassland	GNA	NatureServe
Prosopis glandulosa / Bouteloua curtipendula - Nassella leucotricha Woodland	G3	NatureServe
Prosopis glandulosa / Bouteloua curtipendula Ruderal Shrubland	GNA	NatureServe
Prosopis glandulosa var. glandulosa / Exotic Grass Ruderal Shrubland	GNA	NatureServe
Prosopis glandulosa - Ziziphus obtusifolia Shrubland	G2	NatureServe
Schizachyrium scoparium - Bouteloua curtipendula - Nassella leucotricha Grassland	GNR	NatureServe
Schizachyrium scoparium - (Sorghastrum nutans) - Sporobolus compositus var. compositus - Liatris punctata var. mucronata Grassland	GNR	NatureServe
Vachellia farnesiana - (Prosopis glandulosa) Riparian Woodland	G5	NatureServe

State Conservation Ranks (3)

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
NM	SNR
OK	SNR
TX	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.