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G331 Hesperostipa comata - Bouteloua gracilis Dry Mixedgrass Prairie Group
Type Concept Sentence: This group occurs largely in the northern Great Plains It is found on a variety of dry to dry-mesic upland settings where midgrasses, especially Elymus lanceolatus, Hesperostipa comata, Hesperostipa curtiseta, and Pseudoroegneria spicata, are mixed with shortgrasses and sedges, including Bouteloua gracilis, Carex filifolia, Carex inops ssp. heliophila, and Koeleria macrantha.
Common (Translated Scientific) Name: Needle-and-Thread - Blue Grama Dry Mixedgrass Prairie Group
Colloquial Name: Northern Great Plains Dry Mixedgrass Prairie
Hierarchy Level: Group
Type Concept: This dry mixedgrass prairie grassland is common in southeastern Alberta, southwestern Saskatchewan, south into the northern Great Plains of the United States. The vegetation is dominated by moderate to moderately dense medium-tall and short grasses and scattered shrubs. Dominant midgrass species include Hesperostipa comata, Pascopyrum smithii, Pseudoroegneria spicata, and Elymus lanceolatus. Short grasses, including Bouteloua gracilis and Koeleria macrantha, are common and become dominant in dry locations such as upper slopes. Upland sedges, such as Carex inops ssp. heliophila and Carex filifolia, may also be important components. Calamovilfa longifolia is often found with high cover values on sandier soils. Pascopyrum smithii and Elymus lanceolatus will decline in abundance with grazing pressure, while Bouteloua gracilis and Koeleria macrantha cover increases on degraded sites. Other common species include Hesperostipa curtiseta. Common woody species include Artemisia cana, Symphoricarpos occidentalis, Rhus trilobata, and Sarcobatus vermiculatus. Some examples may range into more of a shrub-steppe. Common forbs include Opuntia polyacantha, Sphaeralcea coccinea, and Artemisia frigida. Fire, drought, and grazing constitute the primary dynamics affecting this group. Its presence is generally correlated with arid areas that have mean precipitation of 350 mm per year or less. Stands occur on a wide variety of landforms, with flat to rolling topography and some low-relief hummocky areas. Surficial materials are predominantly glacial till in the Canadian areas, with some glacio-lacustrine areas. Glacio-fluvial sediments are common along major river valleys, and eolian materials are prevalent in some areas. Predominant soils are deep and well-drained to imperfectly drained, have a thick, dark A horizon and are classed as Brown Chernozems in the Canadian system. Textures are sandy loam to loam, medium- to coarser-textured soils. There are significant areas of Solonetzic soils, characterized by a subsoil hardpan layer with a high proportion of sodium.
Diagnostic Characteristics: This group is separated from ~Northern Great Plains Mixedgrass Prairie Group (G141)$$ based on soil moisture and species composition. Stronger constancy and dominance of short grasses, including Bouteloua gracilis and Koeleria macrantha, mixed with the midgrasses Hesperostipa comata, Pascopyrum smithii, Pseudoroegneria spicata, and Elymus lanceolatus distinguish this type from related mesic mixedgrass types. Upland sedges such as Carex inops ssp. heliophila, and Carex filifolia may also be important components. Other common species include Hesperostipa curtiseta and Opuntia polyacantha. Strong grazing pressures on mesic mixedgrass prairies, which increases the shortgrass component, can blur the distinction between the two types.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Examples of this group may be found on xeric locations in adjacent groups, such as ~Northern Great Plains Mesic Mixedgrass Prairie Group (G141)$$. Because Bouteloua gracilis and Koeleria macrantha tend to increase under grazing pressure, overgrazed sites may superficially resemble some of the associations in this group. Sandy prairie stands in this region are probably placed in ~Great Plains Sand Grassland Group (G068)$$ or ~Great Plains Sand Shrubland Group (G069)$$. There are significant areas of Solonetzic soils, characterized by a subsoil hardpan layer with a high proportion of sodium, and review is needed to determine if they fit here or elsewhere. Review of this group in 2019 (REF) indicates that it does not extend into northeast Colorado; rather shortgrass prairie reaches its limit in southeast Wyoming. This group represents the dry northern mixedgrass vegetation. This type does not extend south of Wyoming (G. Jones pers. comm. 2019, K. Decker pers. comm. 2019). See also Kuchler (1964) type 64.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The vegetation is characterized by a dense to sparse mixture of tall and short grasses interspersed with forbs and short shrubs.
Floristics: Dominant grasses include both the mixedgrass species Hesperostipa comata (= Stipa comata), Pascopyrum smithii, Pseudoroegneria spicata, and Elymus lanceolatus and the shortgrasses Bouteloua gracilis and Koeleria macrantha. The latter become dominant in dry locations such as upper slopes. Upland sedges, such as Carex inops ssp. heliophila and Carex filifolia, may also be important components. Calamovilfa longifolia is often found with high cover values on sandier soils. Pascopyrum smithii and Elymus lanceolatus will decline in abundance with grazing pressure, while Bouteloua gracilis and Koeleria macrantha cover increases on degraded sites. Other common species include Hesperostipa curtiseta. Common woody species include Artemisia cana, Symphoricarpos occidentalis, Rhus trilobata, and Sarcobatus vermiculatus. Some examples may range into more of a shrub-steppe. Common forbs include Opuntia polyacantha, Sphaeralcea coccinea, and Artemisia frigida (Adams et al. 2013).
Dynamics: Drought and grazing constitute the primary processes affecting stand dynamics in this group (Adams et al. 2013). The role of fire may be a third primary process. See Adams et al. (2013) for a discussion of the recovery of dry mixedgrass prairie following cultivation and abandonment.
Environmental Description: Climate: This type is generally found in arid areas that have mean precipitation of 350mm per year or less. Soils/substrate: Stands occur on flat to rolling topography with some low-relief hummocky areas. Surficial materials are predominantly glacial till in the Canadian areas, with some glacio-lacustrine areas. Glacio-fluvial sediments are common along major river valleys, and eolian materials are prevalent in some areas (Adams et al. 2013). Predominant soils are deep and well-drained to imperfectly drained, have a thick, dark A horizon and are classed as Brown Chernozems in the Canadian system. Textures are sandy loam to loam, medium- to coarser-textured soils. There are significant areas of Solonetzic soils, characterized by a subsoil hardpan layer with a high proportion of sodium (Adams et al. 2013).
Geographic Range: This group is common in southeastern Alberta, southwestern Saskatchewan, south into the Great Plains of the United States in Montana and Wyoming and east to western Dakotas.
Nations: CA,US
States/Provinces: AB, MT, ND, SK, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.856981
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 2 Shrub & Herb Vegetation Class | C02 | 2 |
| Subclass | 2.B Temperate & Boreal Grassland & Shrubland Subclass | S18 | 2.B |
| Formation | 2.B.2 Temperate Grassland & Shrubland Formation | F012 | 2.B.2 |
| Division | 2.B.2.Nb Central North American Grassland & Shrubland Division | D023 | 2.B.2.Nb |
| Macrogroup | 2.B.2.Nb.2 Needle-and-Thread - Western Wheatgrass - Plains Rough Fescue Grassland Macrogroup | M051 | 2.B.2.Nb.2 |
| Group | 2.B.2.Nb.2.b Needle-and-Thread - Blue Grama Dry Mixedgrass Prairie Group | G331 | 2.B.2.Nb.2.b |
| Alliance | A4029 Short-bristle Needle-and-Thread - Thick-spike Wheatgrass Grassland Alliance | A4029 | 2.B.2.Nb.2.b |
| Alliance | A4032 Bluebunch Wheatgrass - Western Wheatgrass - Needle-and-Thread Grassland Alliance | A4032 | 2.B.2.Nb.2.b |
| Alliance | A4381 None | A4381 | 2.B.2.Nb.2.b |
| Alliance | A4389 Needle-and-Thread Northern Dry Grassland Alliance | A4389 | 2.B.2.Nb.2.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- Adams, B. W., J. Richman, L. Poulin-Klein, K. France, D. Moisey, and R. L. McNeil. 2013. Range plant communities and range health assessment guidelines for the dry mixedgrass natural subregion of Alberta. Second approximation. Publication No. T/040. Rangeland Management Branch, Policy Division, Alberta Environment and Sustainable Resource Development. Lethbridge, AB.
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- Weaver, J. E., and F. W. Albertson. 1956. Grasslands of the Great Plains: Their nature and use. Johnsen Publishing Co., Lincoln, NE. 395 pp.
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