Montana Field Guide

This group is composed of cliffs, bluffs, and rock outcrops throughout the Great Plains Region in MT. Substrates are sedimentary, typically sandstones and limestones. It is characteristically dry and sparsely vegetated, typically having less than 10% plant cover. There may be small patches of dense vegetation, or scattered plants within these communities. Vegetation is restricted to shelves, cracks and crevices in the rock. This group differs from the Great Plains Badlands in that soil development is much more limited, exposed rock is generally much greater, and the Badlands group can have vegetation cover greater than 10 percent. This group is embedded within the mixed grass and sand prairie regions of eastern Montana and the fescue grasslands of the northwestern Great Plains region. The climate is typical of mid continental regions with long, severe winters and warm summers.

This Group is equivalent to the Great Plains Cliff and Outcrop Ecological System.

Cliffs, Bluffs, Rock Outcrops, Bedrock, Sparsely-Vegetated; Shallow and/or Poorly Developed Soils; Sandstone or Limestone Parent Material; <10% Vascular Plant Cover; Great Plains Region

This Group is scattered throughout the Great Plains region of eastern and central Montana.

In MT, G567 occurs in Level III Ecoregions 42 (Northwestern Glaciated Plains) and 43 (Northwestern Great Plains).

In MT, G567 occurs in these Major Land Resource Areas: 46 - Northern and Central Rocky Mountain Foothills, 52-Brown Glaciated Plains, 53A-Northern Dark Brown Glaciated Plains, 58A,B,C,D-Northern Rolling High Plains, and 60B - Pierre Shale Plains.

Small Patch

This group is composed of cliffs and rock outcrops derived from limestone and sandstone parent materials throughout the Great Plains region in Montana. Landforms such as buttes, mesas, and eroded cliff bands constitute the major landforms. It is found within an arid to semi-arid climate. Parent material and erosional forces are the primary factors influencing their development. Pockets of soil develop below the cliff faces and in cracks and crevices. Plants in the shallow soils are subject to conditions different from those of the surrounding ecosystems (Crow & Ware 2007). Soils are dry and easily erodible, and due to their shallow nature provide a unique environment for plants adapted to these conditions (Graham & Knight 2004). Precipitation ranges from 12 to 26 inches with two-thirds coming during the summer and most of the other third in the spring. The growing season is on average 115 days, although the growing season ranges from 100 days on the Canadian border to 130 days on the Wyoming border.

Vegetation is this group is typically sparse. Trees and shrubs if any are typically short, and mixedgrass species dominate the herbaceous stratum. This group has scattered vascular species found in cracks, depressions, or ledges in the bedrock where some soil can accumulate. Dominant species vary greatly depending on geology of the bedrock, climate, aspect, slope, and slope position. Grass species such as sideoats grama (Bouteloua curtipendula), blue grama (Bouteloua gracilis), prairie sandreed (Calamovilfa longifolia), bluebunch wheatgrass (Elymus spicatus), and Indian ricegrass (Oryzopsis hymenoides) are frequent at some sites. Creeping Juniper (Juniperus horizontalis), Common Juniper (Juniperus communis) and Kinnikinnick (Arctostaphylos uva-ursi) are frequent shrubs and sub-shrubs. Forbs present at these sites are diverse but include Buckwheats (Eriogonum sp), Broom Snakeweed (Gutierrezia sarothrae), Sandworts (Arenaria sp), Bladderpods (Physaria sp), Evening-primrose (Oenothera cespitosa), Stemless Four-nerve-daisy (Tetraneuris acaulis) and Penstemons (Penstemon species). Nonvascular species, especially lichens, may be common on exposed rock.

In Montana, this primarily rock outcrop group includes 1 Alliance and 1 Association within the National Vegetation Classification.

These rock-dominated and sparsely-vegetated communities are influenced by the type of parent rock, elevation, aspect, climate, and both physical and chemical weathering patterns. Erosional and depositional processes are locally important. All of these processes and characteristics can have a strong influence over which species occur within these habitats (Larson et al 2000).

This type is generally not a focus for management or restoration activities. Avoiding or preventing impacts to areas within this type, particularly those that support rare taxa or Species of Concern is the primary means of management.

See Management Section.

J. Drake 2015

S. Mincemoyer, E. Luther, S.V. Cooper, T. Luna, L. Vance

12/5/2024