Print Report

M049 Quercus gambelii - Cercocarpus montanus - Purshia spp. Southern Rocky Mountain Montane Shrubland Macrogroup

Type Concept Sentence: This shrubland macrogroup is found in the foothills, canyon slopes and montane zone of mountains of the southern Rocky Mountains and Colorado Plateau and extends out onto outcrops and canyon slopes in the western and southern Great Plains. The vegetation is characterized by an open to dense shrub layer typically dominated by Cercocarpus montanus, Purshia tridentata, and/or Quercus gambelii, and several other characteristic shrubs.

Common (Translated Scientific) Name: Gambel Oak - Alderleaf Mountain-mahogany - Bitterbrush species Southern Rocky Mountain Montane Shrubland Macrogroup

Colloquial Name: Southern Rocky Mountain Montane Shrubland

Hierarchy Level:  Macrogroup

Type Concept: This macrogroup is found in the foothills, canyon slopes and montane zone of mountains of the southern Rocky Mountains and Colorado Plateau, including the Uinta and Wasatch ranges and the Mogollon Rim and extends out onto outcrops and canyon slopes in the western and southern Great Plains. The vegetation is characterized by an open to dense tall or short, broad-leaved deciduous shrub canopy typically dominated by Cercocarpus montanus, Purshia tridentata, and/or Quercus gambelii, which occasionally reaches small tree size. Many other characteristic shrubs may be codominant such as Amelanchier alnifolia, Amelanchier utahensis, Arctostaphylos patula, Artemisia tridentata, Ceanothus fendleri, Ptelea trifoliata, Prunus virginiana, Purshia stansburiana, Quercus x pauciloba, Rhus trilobata, Ribes cereum, Robinia neomexicana, Rosa spp., Symphoricarpos oreophilus, and Symphoricarpos rotundifolius. The herbaceous layer is sparse to moderately dense and dominated by perennial graminoids. Many forb and fern species can occur, but none has much cover. Annual grasses and forbs are seasonally present. Stands occupy the lower slope positions of the foothill and lower montane zones. Elevations range from 1500 to 2700 m. Stands may occur on level to steep slopes, cliffs, escarpments, rimrock slopes, rocky outcrops, and scree slopes. Soils are typically poorly developed, rocky to very rocky, and well-drained. Fire typically plays an important role in shrublands in this macrogroup.

Diagnostic Characteristics: This Rocky Mountain macrogroup is characterized by an open to dense tall or short, broad-leaved deciduous shrub canopy. Common diagnostic and often dominant species are Cercocarpus montanus, Purshia tridentata, and/or Quercus gambelii, which occasionally reach small tree size. Many other characteristic shrubs are associated with this macrogroup and may be codominant, such as Amelanchier alnifolia, Amelanchier utahensis, Arctostaphylos patula, Artemisia tridentata, Ceanothus fendleri, Ptelea trifoliata, Prunus virginiana, Purshia stansburiana, Quercus x pauciloba, Rhus trilobata, Ribes cereum, Robinia neomexicana, Rosa spp., Symphoricarpos oreophilus, and Symphoricarpos rotundifolius which often form a mixed shrub canopy. The herbaceous layer is not consistent, having sparse to moderately dense cover and mostly composed of perennial graminoids. Characteristic species include Achnatherum scribneri, Bouteloua curtipendula, Carex geyeri, Carex inops, Elymus lanceolatus, Festuca thurberi, Hesperostipa comata, Leymus ambiguus, Muhlenbergia montana, Poa fendleriana, and Pseudoroegneria spicata.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: ~Intermountain Basins Curl-leaf Mountain-mahogany Woodland & Scrub Group (G249)$$ with Cercocarpus ledifolius dominant in the overstory could be moved from ~Intermountain Pinyon - Juniper Woodland Macrogroup (M896)$$ to this macrogroup (M049), as that group overlaps ecologically, floristically, and geographically with associations in this macrogroup (J. Evens pers. comm. 2014).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The vegetation may occur as sparse to dense broad-leaved deciduous shrublands composed of short shrubs (1-2 m) or tall shrubs (2-5 m) that occasionally develop into small trees. Occurrences may be multi-layered, with some short shrubby species occurring in the understory of the dominant overstory species. They can range from dense thickets with little understory to relatively mesic mixed shrublands with a rich understory of shrubs, grasses and forbs. These shrubs often have a patchy distribution with grass growing in between. Scattered trees are occasionally present in stands.

Floristics: This macrogroup is characterized by an open to dense tall or short, broad-leaved deciduous shrub canopy typically dominated by Cercocarpus ledifolius, Cercocarpus montanus, Purshia tridentata, and/or Quercus gambelii, which occasionally reach small tree size. It may form dense thickets with little understory or be relatively open with a rich understory of shrubs, grasses and forbs. Scattered trees are occasionally present and typically include species of Pinus or Juniperus. Other characteristic shrubs that may be codominant include Amelanchier alnifolia, Amelanchier utahensis, Arctostaphylos patula, Artemisia tridentata, Ceanothus fendleri, Cercocarpus intricatus, Ptelea trifoliata, Prunus virginiana, Purshia stansburiana, Quercus x pauciloba, Rhus trilobata, Ribes cereum, Robinia neomexicana, Rosa spp., Symphoricarpos oreophilus, and Symphoricarpos rotundifolius. The herbaceous layer is sparse to moderately dense, ranging from 1-40% cover. Perennial graminoids are the most abundant species, particularly Achnatherum scribneri, Andropogon gerardii, Aristida spp., Bouteloua curtipendula, Bouteloua eriopoda, Bouteloua gracilis, Carex inops, Carex geyeri, Elymus arizonicus, Elymus lanceolatus, Eragrostis spp., Festuca spp., Hesperostipa comata, Hesperostipa neomexicana, Koeleria macrantha, Muhlenbergia montana, and Pseudoroegneria spicata. Many forb and fern species can occur, but none has much cover. Commonly present forbs include Achillea millefolium, Artemisia spp., Geranium spp., Maianthemum stellatum, Thalictrum fendleri, and Vicia americana. Ferns include species of Cheilanthes and Woodsia. Annual grasses and forbs are seasonally present, and weedy annuals are often present where disturbed, at least seasonally.

Dynamics:  Fire typically plays an important role in shrublands in this macrogroup. Depending on fire intensity and shrub species, burning causes die-back of the dominant shrub species in some areas, promoting stump sprouting of the dominant shrubs in other areas, and controlling the invasion of trees into the shrubland system. Natural fires typically result in a mosaic of dense shrub clusters and openings dominated by herbaceous species. In some instances, these associations may be seral to the adjacent Pinus ponderosa, Pinus monophylla, Abies concolor, and Pseudotsuga menziesii woodlands and forests. Ream (1964) noted that on many sites in Utah, Gambel oak may be successional and replaced by Acer grandidentatum.
Environmental Description:  This macrogroup typically occupies the lower slope positions of the foothill and montane zones. Elevations range from 1500 to 3100 m. Stands may occur on level to steep slopes, cliffs, escarpments, rimrock slopes, rocky outcrops, and scree slopes. Climate: Climate is semi-arid and characterized by mostly hot, dry summers with mild to cold winters and annual precipitation of 25 to 70 cm. Precipitation mostly occurs as winter snows but may also consist of some late-summer or monsoonal rains. Soil/substrate/hydrology: Soils are typically poorly developed, rocky to very rocky, and well-drained. Soil texture is variable and includes sand, sandy loam, coarse gravels, loams, and clay loams. Parent materials include alluvium, colluvium, and residuum derived from igneous, metamorphic or sedimentary rocks such as granite, gneiss, limestone, quartz, monzonite, rhyolite, sandstone, schist, and shale.
Geographic Range: This macrogroup is found in the foothills, canyon slopes and montane zone of mountains of the southern Rocky Mountains and Colorado Plateau, including the Uinta and Wasatch ranges and the Mogollon Rim and on outcrops and canyon slopes in the western and southern Great Plains. It ranges from southern New Mexico, extending north into Wyoming, and west into the Intermountain West region, including interior California.

Nations: US

States/Provinces:  AZ, CA, CO, NE?, NM, NV?, SD, UT, WY


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.Nf Western North American Grassland & Shrubland Division D022 2.B.2.Nf
Macrogroup 2.B.2.Nf.1 Gambel Oak - Alderleaf Mountain-mahogany - Bitterbrush species Southern Rocky Mountain Montane Shrubland Macrogroup M049 2.B.2.Nf.1
Group 2.B.2.Nf.1.a Gambel Oak - Serviceberry species - Chokecherry Southern Rocky Mountain Montane Shrubland Group G277 2.B.2.Nf.1.a
Group 2.B.2.Nf.1.b Alderleaf Mountain-mahogany - Wavyleaf Oak - Skunkbush Sumac Foothill Shrubland Group G276 2.B.2.Nf.1.b
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Gambel Oak (413) (Shiflet 1994)
> Littleleaf Mountain-Mahogany (417) (Shiflet 1994)
> Montane Scrub Series (Dick-Peddie 1993)
> Mountain Mahogany - Mixed Shrub Series (Dick-Peddie 1993)
>< Sideoats Grama - Sumac - Juniper (735) (Shiflet 1994)
> True Mountain-Mahogany (416) (Shiflet 1994)
Concept Author(s): Faber-Langendoen et al. (2014)

Author of Description: K.A. Schulz and E.H. Muldavin

Acknowledgements: We have incorporated significant descriptive information previously compiled by M.E. Hall.

Version Date: 10-15-14
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