Montana Field Guide

This grassland group occurs within the montane and subalpine zones of western and central Montana and are characterized by a sparse to dense cover of short to mid-stature, perennial bunchgrasses. Dominants and species composition vary widely by site factors such as elevation, slope, aspect, topographic position, soil depth and composition and to a lesser extent by geography. Idaho Fescue dominated or co-dominated sites are the most prevalent communities within this group and occur across its range and at many different sites. In the north, this group occurs from about 5,000-7,000ft and in southern Montana it is more commonly found from 6,000ft up to 9,500ft in some mountain ranges. Sites range from small meadows to large open grasslands surrounded by montane and subalpine forest types. They may be found on gentle to steep slopes on all aspects. Sites commonly occur in upper elevation Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), spruce-fir (Picea engelmannii-Abies lasiocarpa) and whitebark pine (Pinus albicaulis) forests. In subalpine settings, dry grasslands often occur as small meadows or large open parks surrounded by forest. In general, soil textures are much finer, and soils are often deeper than in the surrounding forests. Lower elevation communities within this group transition seamlessly into G273 Rocky Mountain Low Elevation - Dry Grassland Group. At the highest elevations, it transitions into alpine communities.

This Group is equivalent to the Rocky Mountain Subalpine-Upper Montane Grassland Ecological System.

Dominated by Cool Season Bunchgrasses; Montane and Subalpine Zones; Rocky Mountain Region; Graminoid Cover >25%; Shrub Cover <10%

Typical Dominants: Idaho Fescue (Festuca idahoensis); Rough Fescue (Festuca campestris), Timber Oatgrass (Danthonia intermedia), Slender Wheatgrass (Elymus trachycaulus), Nelson's Needlegrass (Stipa nelsonii), Richardson's Needlegrass (Stipa richardsonii), Spike Fescue (Leucopoa kingii), Pinegrass (Calamagrostis rubescens)

Montane and subalpine grasslands occur in almost all of the mountain ranges in the state on both sides of the Continental Divide. They occur in all of the mountains of western Montana and are very extensive in southwestern ranges such as the Anaconda-Pintlar, Pioneers, Snowcrest, Gravelly, Blacktail, Centennial and Beaverhead Mountains. East of the Continental Divide, the group is well represented on high exposed ridges on the Blackfeet Reservation, and along the eastern edge of Glacier National Park. It extends south along the Rocky Mountain Front to west-central Montana and south-central Montana, including the Gallatin, Madison, Absaroka, Beartooth, Pryor, and Bighorn Ranges. It also occurs in the island mountain ranges of central Montana.

In MT, G267 occurs within these Level III Ecoregions: 15 (Northern Rockies), 16 (Idaho Batholith), 17 (Middle Rockies), 41 (Canadian Rockies), and the very western portion of 42 (Northwestern Glaciated Plains).

In Montana, G267 occurs within these Major Land Resource Areas: 43A - Northern Rocky Mountains, 43B - Central Rocky Mountains, 44B - Central Rocky Mountain Valleys, and 46 - Northern and Central Rocky Mountain Foothills.

Large Patch

This grassland group occurs within the montane and subalpine zones of western and central Montana. In the north, it occurs from about 5,000-7,000ft and in southern Montana it is more commonly found from 6,000ft up to 9,500ft in some mountain ranges. Sites range from small meadows to large open grasslands surrounded by high elevation forest types. They may be found on gentle to steep slopes on all aspects. Sites commonly occur in upper elevation Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), spruce-fir (Picea engelmannii-Abies lasiocarpa) and whitebark pine (Pinus albicaulis) forests. At the highest elevations, it transitions into alpine communities. Soils range from shallow to deep depending on topography but tend to be deeper than soils in adjacent forest communities or in alpine plant communities. Annual precipitation falls mainly as snow in the mountains with spring rains and early summer convective storms common providing moisture during the growing season.

These montane and subalpine grasslands are characterized by a sparse to dense cover of short to mid-stature, perennial bunchgrasses. Sites on shallow, rocky to gravelly soils may have a low cover of graminoids (<10-25%). These often occur on steeper slopes, upper slopes or along ridgetops. Well-developed expressions of these communities, occurring on deeper soils and gentler slopes often have graminoid cover >50%. Common species in this group, include Idaho Fescue (Festuca idahoensis), Rough Fescue (Festuca campestris), Timber Oatgrass (Danthonia intermedia), Nelson’s Needlegrass (Stipa nelsonii), Richardson’s Needlegrass (Stipa richardsonii), Prairie Junegrass (Koeleria macrantha), Slender Wheatgrass (Elymus trachycaulus), Pinegrass (Calamagrostis rubescens), Tufted Hairgrass (Deschampsia cespitosa), and Spike Fescue (Leucopoa kingii). Many of the dominant species occur across the range of the type while Spike Fescue is limited to extreme southern Montana and Richardson’s Needlegrass is more prevalent in the northern half of the state. Dominants and species composition vary widely by site factors such as elevation, slope, aspect, topographic position, soil depth and composition and to a lesser extent by geography. Idaho Fescue dominated or co-dominated sites are the most prevalent communities within this group and occur across its range and at many different sites. Lower elevation communities within this group transition seamlessly into G273 Rocky Mountain Low Elevation - Dry Grassland, particularly sites dominated by Idaho Fescue and Rough Fescue. At higher subalpine elevations, Alpine Timothy (Phleum alpinum), Tufted Hairgrass (Deschampsia cespitosa), Spike Trisetum (Trisetum spicatum), Hood’s sedge (Carex hoodii), Carex obtusata, and Carex scirpoidea are common components.

These grasslands support a rich, forb flora, including many species that occur in lower elevation grasslands, including arrowleaf balsamroot (Balsamorhiza sagittata), yarrow (Achillea millefolium), silky lupine (Lupinus sericeus), sticky geranium (Geranium viscosissimum), nine-leaf biscuitroot (Lomatium triternatum), prairie cinquefoil (Potentilla gracilis), Penstemons, little larkspur (Delphinium bicolor), wild strawberry (Fragaria virginiana), paintbrush (Castilleja species), boreal bedstraw (Galium boreale), prairie smoke (Geum triflorum), fringed sage (Artemisia frigida), western sagewort (Artemisia ludoviciana), prairie alumroot (Huechera parviflora), rosy pussytoes (Antennaria rosea), woolly groundsel (Packera cana), Phlox spp., buckwheat (Eriogonum species), fireweed (Chamerion angustifolium), and cut-leaf daisy (Erigeron compositus). Common subalpine components include Blue-leaved Cinquefoil (Potentilla glaucophylla and Rocky Mountain Goldenrod (Solidago multiradiata).

Shrub species may be scattered among these grasslands, especially shrubby cinquefoil (Dasiphora fruticosa), Woods’ rose (Rosa woodsii), bearberry (Arctostaphylos uva-ursi), and common juniper (Juniperus communis).

In Montana, this group is represented by 17 Associations grouped into 3 Alliances within the National Vegetation Classification, which likely captures the range of vegetation types present in the state within this group.

Fires have historically helped to maintain these montane and subalpine grasslands by removing conifers encroaching into these habitats. Fire return intervals in montane grassland- Douglas-fir ecotones in southwestern Montana are estimated at 35 to 40 years, although they may be shorter in the grasslands proper (Arno and Gruell, 1983). With fire suppression, shrubs may increase, and trees may encroach into these grasslands, resulting in a loss of habitat. Conversely, fires burning in stands of Mountain big sagebrush (Artemisia tridentata ssp. vaseyana) which is common in southwestern Montana, may result in elimination of sagebrush and development of these grassland habitats.

In the absence of natural fire, periodic prescribed burns and appropriate grazing management practices can be used to maintain this system. Rough fescue is highly palatable throughout the grazing season, so tends to attract livestock use. Summer overgrazing for a two to three year period can result in the loss of Rough Fescue (Willms and Rhode 1998). Even at moderate stocking rates, livestock grazing decreases cover of Rough Fescue, especially during summer months. Oatgrass tends to replace rough Fescue under moderate or heavy grazing pressure (Willms and Rhode, 1998). Proper Grazing management or removing livestock grazing from these sites can avert the loss of Rough fescue and the replacement with less desirable species.

Invasive species threaten many of these grasslands. On lower elevation, drier sites, Sulfur Cinquefoil (Potentilla recta), Leafy Spurge (Euphorbia virgata), and Spotted Knapweed species (Centaurea stoebe) are problematic. Mesic sites within this system are threatened by the Meadow Hawkweed complex (Hieracium pratense, H. floribundum, H. piloselliodes), Orange Hawkweed (Hieracium aurantiacum), Ox-eye Daisy (Leucanthemum vulgare), Tall Buttercup (Ranunculus acris), and Canada Thistle (Cirsium arvense). Introduced grasses such as Smooth Brome (Bromus inermis), Common Timothy (Phleum pratense) and Kentucky Bluegrass (Poa pratensis), are common and widespread within these habitats.

Restoration strategies will depend largely on the disturbance and severity. Modified grazing practices and periodic prescribed fires can help this system to recover without additional restoration. On reclamation sites where soil preparation is required, soil disking techniques that discourage uniform soils and seed beds are preferable. Feathering and smoothing topsoil may benefit invasive species such as Kentucky bluegrass (Poa pratensis) and smooth brome (Bromus inermis), while uneven soil conditions may inhibit their growth, allowing rough fescue (Festuca campestris) and other desirable grasses to establish more readily (Desserud 2006).

M.S. Reid and K.A. Schulz 2015

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

12/4/2024