Common (Translated Scientific) Name: Great Plains Cliff, Scree & Rock Vegetation Macrogroup
Colloquial Name: Great Plains Cliff, Scree & Rock Vegetation
Hierarchy Level: Macrogroup
Type Concept: This macrogroup consists of cliffs, bluffs, and rock outcrops in the Great Plains from the U.S.-Canadian border area south to Texas. It is defined by having sparse vascular vegetation, cryptograms and an abundance of exposed bedrock. The bedrock exposure can be vertical, sloping, or horizontal along rivers, at the tops of buttes, in dry canyons, or, rarely, large, low bedrock outcrops. The bedrock is usually sedimentary (sandstone, limestone, shale, gypsum, siltstone), but granite, rhyolite and (rarely) quartzite also occur. Vegetation is generally sparse except where soil accumulates in pockets or ledges. Dominant species vary greatly depending on geology of the bedrock, climate, aspect, slope, and slope position. Lichens predominate on exposed rock. Common vascular species found in this macrogroup are able to tolerate the dry to xeric conditions and poor soil development. These include Bouteloua eriopoda (in the southwest), Bouteloua gracilis, Bouteloua hirsuta, Bouteloua rigidiseta, Cercocarpus montanus, Erioneuron pilosum, Juniperus spp., Opuntia spp., Rhus trilobata, and Vulpia octoflora. Cryptogams, especially lichen species, need to be described.
Diagnostic Characteristics: This macrogroup is characterized by sparse, rocky vegetation (generally <10% vascular cover) on consolidated rock outcrops or scree/talus fields below cliffs in the Great Plains. Nonvascular species, especially lichens, can be very common on exposed rock.
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: The concept of this macrogroup is fairly distinct within the Great Plains though individual sites may have enough vegetation to be confused with dry prairie or dry woodland macrogroups. This macrogroup is largely defined by the Great Plains vascular flora associated with it, and it is on that basis that we separate it from other open bedrock macrogroups, both in the East, i.e., Eastern North American Cliff & Rock Vegetation Macrogroup (M111), and the West, i.e., Western North American Cliff, Scree & Rock Vegetation Macrogroup (M887), as well as more vascular-dominated rocky types, such as Southern Barrens & Glade Macrogroup (M308), that contain rocky grasslands. Badlands vegetation in Great Plains Badlands Vegetation Macrogroup (M115) is distinct in its substrate (thin erodible clays and silts over bedrock), sparse vascular vegetation, and lack of cryptogams, especially lichens.
Similar NVC Types:
M118 Intermountain Basins Cliff, Scree & Badland Sparse Vegetation, note:
M111 Eastern North American Cliff & Rock Vegetation, note:
M115 Great Plains Badlands Vegetation, note: "is distinct in its substrate (thin erodible clays and silts over bedrock), sparse vascular vegetation, and rarely contains cryptogams, such as lichens."
M308 Southern Barrens & Glade, note: "is found generally south and east of M116, but where their ranges are adjacent or overlap in the southern Great Plains, better diagnostic criteria are needed."
Physiognomy and Structure: Examples of this macrogroup have low, sparse vascular vegetation and a range of nonvascular, typically lichen, cover. The most abundant vascular species at a site are usually small trees, shrubs or grasses but can be forbs in a few cases. Trees and shrubs are typically short, and mixedgrass species dominate the herbaceous stratum. Nonvascular cover is not well-described.
Floristics: Species composition is a product of soil depth. In locations and patches where soils are the shallowest, only drought-tolerant plants will persist, many of which are annuals. The number of perennial taxa increases with increasing soil depth. On exposed rock surfaces, the dominant species may be nonvascular plants such as lichens. Common grass species include Aristida oligantha, Bouteloua curtipendula, Bouteloua hirsuta, Bouteloua rigidiseta, Erioneuron pilosum, Schizachyrium scoparium, and Vulpia octoflora (= Festuca octoflora). Common forbs are Asclepias pumila, Calylophus hartwegii, Chaetopappa asteroides, Chaetopappa ericoides, Cheilanthes feei, Croton monanthogynus, Dalea enneandra, Echinacea angustifolia, Echinocereus reichenbachii, Eriogonum flavum, Eriogonum longifolium, Evolvulus nuttallianus, Haploesthes greggii, Stenaria nigricans, Heliotropium tenellum, Hybanthus verticillatus, Lesquerella gordonii, Lesquerella ovalifolia, Mentzelia oligosperma, Nama stevensii, Pellaea atropurpurea, Pediomelum cuspidatum, Penstemon cobaea, Penstemon fendleri, Paronychia jamesii, Plantago patagonica, Plantago wrightiana, Scutellaria wrightii, Sedum nuttallianum, Sedum pulchellum, Selaginella peruviana, Symphyotrichum fendleri, and Thelesperma ambiguum. When present, woody taxa might include Cissus trifoliata, Forestiera pubescens, Juniperus ashei, Juniperus monosperma, Juniperus pinchotii, Juniperus virginiana, Mimosa borealis, Quercus mohriana, Rhus aromatica, Sapindus saponaria, and Sideroxylon lanuginosum.
Common trees and shrubs are junipers, including Juniperus monosperma (in the southwest), Juniperus scopulorum (in the west), Juniperus virginiana (in the east and north), Juniperus communis, Juniperus horizontalis, and other shrubs, such as Artemisia longifolia, Cercocarpus montanus, Rhus trilobata, and Ribes aureum. Common grasses include Bouteloua eriopoda (in the southwest), Bouteloua gracilis, Bouteloua hirsuta, Bouteloua rigidiseta, Calamovilfa longifolia, Cercocarpus montanus, Erioneuron pilosum, Pseudoroegneria spicata (in the northwest), Schizachyrium scoparium, and Vulpia octoflora. Nonvascular species, especially lichens, can be very common on exposed rock, and further review of their species composition is needed.
Dynamics: Drought and erosion, both from wind and water, are important in maintaining sites in this macrogroup. These factors, combined with the steep slopes on many sites, greatly limit the species that can exist.
Environmental Description: Climate: The division occurs within two climate types (sensu Trewartha): Temperate Continental and Dry Steppe (semi-arid). As a result, there are distinct gradients of precipitation and temperate within the division. The precipitation gradient extends along an east-to-west axis, with an average annual precipitation of 1014mm at Lawrence, Kansas, to 477.5mm at Boise City, Oklahoma. The western extent of the region is subject to periodic, often severe, droughts. The temperature gradient follows a south-north gradient. The annual average temperature in the southern extent of the division is 18.6°C (mean high of 25.7°C and a mean low 11.6°C) at San Angelo, Texas, to 3.1°C in Regina, Saskatchewan (a mean high of 18.9°C in July and a mean low of -14.7°C). Nevertheless, these sites all tend to be xeric and very hot during the summer months.
Soils/substrate: Sites in this macrogroup have significant exposure of bedrock. The bedrock can be vertical, sloping, or horizontal along rivers, at the tops of buttes, in dry canyons, or, rarely, large, low bedrock outcrops. The bedrock is usually sedimentary (sandstone, limestone, shale, gypsum, siltstone), but granite and rhyolite also occur and in southwestern Minnesota, an area of quartzite outcrops is included in this macrogroup. Soil development is limited to cracks, ledges, or depressions in the bedrock. Soils are dry and easily erodible. This macrogroup is found in an arid to semi-arid climate with infrequent heavy summer rains that can erode soils that have developed.
Geographic Range: This macrogroup is found in the Great Plains from southern Canadian Great Plains south to northern Texas, and from the Rocky Mountain foothills to southwestern Minnesota, eastern Kansas and possibly northwestern Iowa and Missouri.
Nations: CA, US
States/Provinces: AB, CO, IA?, KS, MB, MN, MO?, MT, ND, NE, NM, OK, SD, SK?, TX, WY
|US Forest Service Ecoregions (2007)|
Southwest Plateau and Plains Dry Steppe and Shrub Province
Confident or certain
Western Great Plains Section
Confident or certain
Confidence Level: High
Confidence Level Comments:
Synonomy: = Crystalline Bedrock Outcrop (Prairie) Type [ROs12a] (Minnesota DNR 2005b)
Concept Author(s): Faber-Langendoen et al. (2014)
Author of Description: J. Drake, D. Faber-Langendoen and B. Hoagland
Version Date: 14Jan2016
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- Collins, S. L., G. S. Mitchell, and S. C. Klahr. 1989. Vegetation-environment relationships in a rock outcrop community in southern Oklahoma. American Midland Naturalist 122:339-348.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Minnesota DNR [Minnesota Department of Natural Resources]. 2005b. Field guide to the native plant communities of Minnesota: The Prairie Parkland and Tallgrass Aspen Parklands provinces. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul.
- Uno, G. E., and S. L. Collins. 1987. Primary succession on granite outcrops of southwestern Oklahoma. Bulletin of the Torrey Botanical Club 114:387-392.