Name:
Hesperostipa comata - Pascopyrum smithii - Festuca hallii Grassland Macrogroup
Reference:
NatureServe Biotics 2019
Description:
The macrogroup is dominated by mixed grasses and scattered to moderately dense shrubs. It is found from northern Texas to southern Alberta. The most common graminoid species occurring across the range of the macrogroup include <i>Hesperostipa comata</i> and <i>Pascopyrum smithii</i>. Northern examples are typically dominated by <i>Festuca</i> spp., especially <i>Festuca hallii</i>, in combination with <i>Bouteloua gracilis, Hesperostipa curtiseta, Koeleria macrantha, Pascopyrum smithii, Poa pratensis</i>, and <i>Symphoricarpos occidentalis</i>. Southern examples are more likely to be dominated by species such as <i>Aristida purpurea, Bothriochloa laguroides ssp. torreyana, Bouteloua curtipendula, Schizachyrium scoparium</i>, and <i>Sporobolus cryptandrus</i>. The most mesic sites can have abundant tallgrasses, especially <i>Andropogon gerardii, Panicum virgatum</i>, and <i>Sorghastrum nutans</i>. Other common associated species include <i>Bouteloua gracilis, Bouteloua dactyloides, Carex filifolia, Carex inops ssp. heliophila, Calamovilfa longifolia, Elymus lanceolatus, Festuca idahoensis, Hesperostipa curtiseta, Hesperostipa neomexicana, Koeleria macrantha, Muhlenbergia montana, Nassella leucotricha, Nassella viridula, Pseudoroegneria spicata, Sorghastrum nutans</i>, and <i>Sporobolus compositus</i>. Common forb species tend to be somewhat restricted but may include <i>Achillea millefolium, Ambrosia psilostachya, Amphiachyris dracunculoides, Artemisia ludoviciana, Cerastium arvense, Dalea purpurea, Echinacea angustifolia, Galium boreale, Hymenopappus scabiosaeus, Liatris punctata, Lygodesmia juncea, Pediomelum linearifolium</i>, and <i>Symphyotrichum falcatum</i>. Woody species can occur and include <i>Amelanchier alnifolia, Artemisia cana, Dasiphora fruticosa ssp. floribunda, Juniperus horizontalis, Prosopis glandulosa, Prunus virginiana, Rhus trilobata, Rosa arkansana</i>, and <i>Symphoricarpos occidentalis</i>. Isolated patches of <i>Quercus macrocarpa</i> also can occur. Some examples may range into shrub-steppe. Grazing and fire are important dynamic processes in this macrogroup and can significantly influence the distribution and dominance of species within it. Fire suppression and overgrazing within the region has enabled the invasion of both exotics and some shrub species such as <i>Juniperus virginiana</i> and <i>Prosopis glandulosa</i>. These factors have also allowed for the establishment of <i>Pinus ponderosa</i> in the northwestern parts of the range. Conversion to agriculture likewise has decreased the range of this macrogroup. This type is found in regions centered between the shortgrass prairies in the western Great Plains and the tallgrass prairies in the eastern Great Plains. It occurs on both glaciated and non-glaciated substrates on a wide variety of landforms. The distribution, species richness and productivity of plant species is controlled by environmental conditions, in particular soil moisture and topography. Soils range from fine-textured loams to sandy or gravelly soils. Northern examples of this macrogroup contain significant areas of solonetzic soils, characterized by a subsoil hardpan layer with a high proportion of sodium and may also be clay, silty clay, or loam. The relative dominance of the various grass and forb species within different associations in the macrogroup also can strongly depend on the degree of natural or human disturbance. Because of its proximity to other prairie types, this macrogroup contains elements from both shortgrass and tallgrass prairies, which combine to form the mixedgrass prairie throughout its range.
Accession Code:
urn:lsid:vegbank.org:commConcept:40471-{FC884BCD-B63D-4F80-9836-F2744D70DA11}
Plot-observations of this Community Concept:
0
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