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Great Plains Dry Bur Oak Forest

EVT 7013Western Great Plains Dry Bur Oak Forest and Woodland

CES303.667G3TreeHardwood

Summary

This system is dominated by Quercus macrocarpa and is found in upland areas in the northern part of the Western Great Plains. It often occurs as small to large patches on buttes, escarpments, and in foothill zones, usually on northerly-facing slopes. Other species, such as Tilia americana (not in the Dakotas), Populus tremuloides, Juniperus virginiana, and Fraxinus spp., may be present. The herbaceous layer can vary from sparsely to moderately vegetated and is composed of prairie grasses or woodland Carex spp. Shrub associates can include Prunus virginiana, Corylus cornuta, Amelanchier alnifolia, or Symphoricarpos spp. Historically, higher cover of grass species occurred as these stands were more open due to more frequent fires. Few good examples of this system likely remain because of past timber harvesting and heavy grazing. Where it occurs at elevations above 915 m (3000 feet), Pinus ponderosa woodlands are probably adjacent.

Source: NatureServe Explorer

Vegetation

This system is typified by the predominance of Quercus macrocarpa constituting at least 10% of the vegetation cover in any given example of this system. Other species, such as Tilia americana, Juniperus virginiana, and Fraxinus spp., may be also present. Understory vegetation can range from sparsely vegetated to more dense and usually exemplifies the surrounding prairie grassland vegetation.

Source: NatureServe Explorer

Environment

This system is found in upland areas throughout the northern part of the Western Great Plains. Soils are predominately dry to mesic. It usually occurs on protected eastern or northern slopes of buttes or river valleys (Rolfsmeier and Steinauer 2010).

Source: NatureServe Explorer

Dynamics

This system is primarily driven by fire. This system occurs in a landscape where fire is common but the sites it occupies are somewhat sheltered so fire frequency is less than the surrounding prairie uplands. Fire-return intervals have been estimated at 15-25 years (Landfire 2007a). Fire reduces woody species regeneration and shrub cover and allows prairie grasses to grow under the open tree canopy.

Source: NatureServe Explorer

Threats

Grazing, conversion to agriculture, and timber harvesting can impact this system. Overgrazing can lead to a decrease in native understory species and an increase in exotic species. Timber harvesting can remove mature trees and impact the understory through the effects of logging equipment or can completely eliminate examples of this system. Reduction in fire frequency allows fire-sensitive species to spread and results in less cover by native grasses and fire-tolerant shrubs. The tree and shrub canopy will close in over time without fire, which will further impact the understory by reducing available light.

Source: NatureServe Explorer

Distribution

This system is found throughout the northern part of the Western Great Plains Division. In Wyoming, it occurs in the Bear Lodge Mountains and around Devils Tower National Monument. In North Dakota, it is found in the Killdeer Mountains, and it may occur in the Pine Ridge region of Nebraska.

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

Fraxinus pennsylvanica, Juniperus virginiana, Pinus ponderosa, Populus tremuloides, Prunus virginiana, Quercus macrocarpa, Tilia americana

Shrub/sapling (tall & short)

Amelanchier alnifolia, Corylus cornuta, Symphoricarpos occidentalis

Herb (field)

Aralia nudicaulis, Carex sprengelii, Maianthemum stellatum

Source: NatureServe Ecological System assessment

Ecologically Associated Animals (2)

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
Prairie Rattlesnake	Crotalus viridis	G5
Gophersnake	Pituophis catenifer	G5

Source: NatureServe Ecological System assessment

Component Associations (6)

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
Quercus macrocarpa / Cornus drummondii / Aralia nudicaulis Forest	G4	NatureServe
Quercus macrocarpa / Corylus americana - Amelanchier alnifolia Woodland	G3	NatureServe
Quercus macrocarpa / Corylus cornuta Woodland	G2	NatureServe
Quercus macrocarpa - Populus tremuloides / Aralia nudicaulis Forest	GNR	NatureServe
Quercus macrocarpa - Populus tremuloides / Corylus spp. Woodland	G4	NatureServe
Tilia americana - (Quercus macrocarpa) / Ostrya virginiana Forest	G3	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
ND	SNR
SD	SNR
WY	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.