Montana Field Guide

This grassland system of the northern Rocky Mountains is found at lower montane to foothill elevations in mountains and valleys throughout Montana. These grasslands are floristically similar to Big Sagebrush Steppe but are defined by shorter summers, colder winters, and young soils derived from recent glacial and alluvial material. They are found at elevations from 548 - 1,650 meters (1,800-5,413 feet). In the lower montane zone, they range from small meadows to large open parks surrounded by conifers; below the lower treeline, they occur as extensive foothill and valley grasslands. Soils are relatively deep, fine-textured, often with coarse fragments, and non-saline. Microphytic crust may be present in high-quality occurrences. This system is typified by cool-season perennial bunch grasses and forbs (>25%) cover, with a sparse shrub cover (<10%). Rough fescue (Festuca campestris) is dominant in the northwestern portion of the state and Idaho fescue (Festuca idahoensis) is dominant or co-dominant throughout the range of the system. Bluebunch wheatgrass (Pseudoroegneria spicata) occurs as a co-dominant throughout the range as well, especially on xeric sites. Western wheatgrass (Pascopyrum smithii) is consistently present, often with appreciable coverage (>10%) in lower elevation occurrences in western Montana and virtually always present, with relatively high coverages (>25%), on the edge of the Northwestern Great Plains region. Species diversity ranges from a high of more than 50 per 400 square meter plot on mesic sites to 15 (or fewer) on xeric and disturbed sites. Most occurrences have at least 25 vascular species present. Farmland conversion, noxious species invasion, fire suppression, heavy grazing and oil and gas development are major threats to this system.

This fescue-dominated grassland is transitional between the mixed grass prairie and montane/subalpine grasslands occurring adjacent to or within forested habitats. In northern Montana, it is often associated with aspen parkland. Rough fescue (Festuca campestris) and Idaho fescue (Festuca idahoensis) are the dominants in northwestern Montana. To the west, this system grades into Palouse prairie in northern Idaho and contains many of the same species. Average precipitation ranges from 292-406 millimeters (11.5 to 16.5 inches). Mean temperatures increase on the eastern edge of this system. Where it occurs within glaciated landscapes, numerous pothole wetlands and other wetland systems are found, often characterized by a perimeter of willow (Salix species).

In northwestern and west-central Montana, this ecosystem forms in openings in Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) forests, and in intermountain and mountain valleys and big sagebrush (Artemisia tridentata) shrublands. East of the Continental Divide, this system is found along valley bottoms and steep canyon slopes at montane elevations along the Rocky Mountain Front to west-central Montana. Rolling uplands and undulating plains are typical topography east of the Continental Divide, from the Alberta border south along the Rocky Mountain Front and east where this system merges with mixed prairie grassland. Much of this area is cultivated. Black Chernozems are the dominant soils, reflecting moister, cooler conditions and the incorporation of relatively high amounts of organic matter.

In Montana, two plant communities dominate this system: 1) Rough Fescue - Idaho Fescue, found on moister sites such as the north- and east-facing slopes in foothills and swales in the northwestern edge of the Great Plains and valley bottoms with deeper soils; and 2) Bluebunch Wheatgrass - Idaho Fescue, found on drier sites such as ridges, hilltops, and south- and west-facing slopes in the foothills and on level sites with sharply drained glacial-till soils.

On pristine, moist sites, rough fescue can form a nearly continuous cover, interspersed with Idaho fescue and the rhizomatous ecotype of bluebunch wheatgrass. Other graminoids include western needlegrass (Achnatherum occidentale), Richardson’s needlegrass (Achnatherum richardsonii), oatgrass (Danthonia species), prairie junegrass (Koeleria macrantha), Sandberg’s bluegrass (Poa secunda), western wheatgrass (Pascopyrum smithii), thickspike wheatgrass (Elymus lanceolatus), basin wildrye (Leymus cinereus), and Liddon sedge (Carex petasata). These moister sites support a forb- rich community that includes species such as arrowleaf balsamroot (Balsamorhiza sagittata), yarrow (Achillea millefolium), silky lupine (Lupinus sericeus), sticky geranium (Geranium viscossisimum), nine-leaf biscuitroot (Lomatium triternatum), sticky cinquefoil (Potentilla glandulosa), prairie cinquefoil (Potentilla gracilis), sulphur penstemon (Penstemon confertus), little larkspur (Delphinium bicolor), crazyweed (Oxytropis species), prairie gentian (Gentiana affinis), wild strawberry (Fragaria virginiana), and Indian paintbrush (Castilleja species).

Shrub cover is usually less than 10 percent and includes species such as shrubby cinquefoil (Dasiphora fruticosa), Woods’ rose (Rosa woodsii), snowberry (Symphoricarpos species), and common juniper (Juniperus communis). Serviceberry (Amelanchier alnifolia), Douglas hawthorn (Crataegus douglasii), and common chokecherry (Prunus virginiana) often occur as patches on north-facing slopes of foothills where snow persists longer into the growing season.

On drier sites dominated by Idaho fescue and the bunchgrass ecotype of bluebunch wheatgrass, common forbs include yarrow, Indian blanketflower (Gaillardia aristata), boreal bedstraw (Galium boreale), prairie smoke (Geum triflorum), prairie arnica (Arnica sororia), rosy pussytoes (Antennaria microphylla), prairie cinquefoil, silver lupine (Lupinus argenteus), silky lupine,early biscuitroot (Lomatium macrocarpum), alyssum leaf phlox (Phlox alyssifolia), Hood’s phlox (Phlox hoodii), gayfeather (Liatris punctata), stoneseed (Lithospermum ruderale), buckwheat (Eriogonum species), fuzzytongue penstemon (Penstemon eriantherus), Missouri goldenrod (Solidago missouriensis), crazyweed (Oxytropis species), alumroot (Huechera species), prairie crocus (Pulsatilla patens), brittle prickly pear (Opuntia fragilis), western sagewort (Artemisia ludoviciana), boreal sagewort (Artemisia frigida), and daisy (Erigeron species). Endemic species are common in drier, rocky sites along the northwestern edge of the Great Plains, e.g., Rocky Mountain douglasia (Douglasia montana), shining penstemon (Penstemon nitidus), and Alberta penstemon (Penstemon albertinus). Other graminoids present within this drier community includetimber oatgrass (Danthonia intermedia), prairie junegrass (Koeleria macrantha), Sandberg’s bluegrass (Poa secunda), Indian ricegrass (Achnatherum hymenoides), Geyer’s sedge (Carex geyeri), andthreadleaf sedge (Carex filifolia). Lesser spikemoss (Selaginella densa) may be present in high cover on some sites. Lichen cover can be high on ungrazed occurrences (Antos et al,1983) or where fire has been suppressed. Moss can be variable, depending on level of disturbance.

Shrubs may increase following heavy grazing and/or with fire suppression. Rough fescue is highly palatable throughout the grazing season. Summer overgrazing for 2 to 3 years can result in rough fescue loss. In one study, although a light stocking rate for 32 years did not affect range condition, a modest increase in stocking rate led to a marked decline in range condition (Willms and Rhode, 1998). Oatgrass tends to replace rough fescue under moderate or heavy grazing pressure. Long-term heavy grazing on moister sites can result in a shift to a Kentucky bluegrass (Poa pratensis)/timothy(Phleum pratense)/ smooth brome (Bromus inermis) type.

In Montana, many exotic species invaded these grasslands, and in some cases have completely replaced native species. On disturbed, drier sites, Japanese brome (Bromus japonicus), sulfur cinquefoil (Potentilla recta), leafy spurge (Euphorbia esula), spotted knapweed (Centaurea biebersteinii), Saint John’s wort (Hypericum perforatum), and whitetop (Cardaria draba) are common. Mesic sites are threatened by 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).

Restoration strategies will depend largely on disturbance severity.Modified grazing practices can allow this system to recover without additional restoration needs. Antos and others (1983) have suggested prescribed fires at intervals of every 5 to 10 years for sites in western Montana. Following burning and depending on fire intensity, rough fescue may recover at much slower rates than Idaho fescue (Antos et al., 1983). Short-term conditions after burning, e.g., precipitation and cold-stress days, appear important in controlling species responses and composition of plant communities (Gross and Romo, 2009).

On some sites, site preparation will require noxious species eradication and control for at least two seasons before and after restoration. On reclamation sites where soil preparation is required, soil disking techniques that discourage uniform soils and seed beds should be used. Feathering and smoothing topsoil may benefit invasive species such as Kentucky bluegrass (Poa pratensis) and smooth brome (Bromus inermis), while rough conditions may inhibit their growth, allowing rough fescue (Festuca campestris) and its associated grasses to establish more readily (Desserud, 2006).