Montana Field Guide

In Montana, this system occurs above upper treeline throughout the Montana Rocky Mountain ranges, and east into the mountain island ranges. Elevation ranges from as low as 6,600 ft in northwestern to 10,500 feet in southwestern Montana. Turf communities form on gentle to moderate upper slopes, flat ridges, valleys, basins, and gentle summit ridges where soil has become relatively stabilized and the water supply persists until fall. At these elevations, the growing season typically ranges from 60 to 90 days. During the growing season, these areas are subjected to windy conditions and widely variable diurnal temperatures. Freezing temperatures and snow can occur throughout the summer months. Turf communities are composed of a diversity of rhizomatous sedges, rushes, woodrushes, grasses and forbs that form a dense turf that is rarely greater than 12 cm (5 inches) tall. Depending on slope protection, soil development, snow depth, turf communities can range from dry to mesic expressions.

Throughout Montana, alpine turf supports a high diversity of sedges, grasses and forbs. Common graminoid species include alpine bluegrass (Poa alpina), alpine timothy (Phleum alpinum), alpine fescue (Festuca brachyphylla), and a highly diverse assemblage of sedges including northern singlespike sedge (Carex scirpoidea), curly sedge(C. rupestris), blackroot sedge (Carex elynoides ), obtuse sedge (Carex obtusata), dunhead sedge (Carex phaeocephala), Hayden’s sedge (Carex haydeniana), spiked woodrush (Luzula spicata), and Piper’s woodrush (Luzula piperi). Alpine forbs can often form nearly half the cover in turf communities and can include diverse leaf cinquefoil (Potentilla diversifolia), alpine goldenrod (Solidago multiradiata), moss campion (Silene acaulis), Parrot’s beak lousewort (Pedicularis contorta), arnica (Arnica species), alpine pussytoes (Antennariaspecies), subalpine wandering daisy (Erigeron peregrinus), sibbaldia (Sibbaldia procumbens), glacier lily (Erythronium grandiflorum), and rhexi-leaf paintbrush (Castilleja rhexifolia),among many others. Woody, mat forming species such as arctic willow (Salix arctica) and bearberry (Arctostaphylos uva-ursi) can contribute significant cover in many examples of turf communities. Due to the very slow rate of community development, short growing season, and limited soil development, alpine turf cannot support heavy levels of disturbance such as repeated grazing, land disturbance and heavy foot traffic. Recovery of these communities occurs over many decades. Climatic warming and decreasing snowpack levels will alter the floristic composition and the distribution of peripheral species, northern Rocky Mountain endemics and rare species that occur within it.

Turf communities are composed of a diversity of rhizomatous sedges, rushes, woodrushes, grasses and forbs that form a dense turf that is rarely greater than 12 cm (5 inches) tall. Depending on slope protection, soil development, snow depth, turf communities can range from dry to mesic. In northwestern Montana, dry turf communities are dominated by graminoids. Common species include alpine bluegrass (Poa alpina), alpine timothy (Phleum alpinum), alpine fescue (Festuca brachyphylla), dunhead sedge (Carex phaeocephala), spiked woodrush (Luzula spicata), Piper’s woodrush (Luzula piperi), and Hayden’s sedge (Carex haydeniana).

Alpine forb cover is usually less than 40% in the drier expression of alpine turf communities. Common species include forbs include diverse leaf cinquefoil (Potentilla diversifolia), alpine goldenrod (Solidago multiradiata), moss campion (Silene acaulis), Parrot’s beak lousewort (Pedicularis contorta), arnica (Arnica species), Eschscholtz’s buttercup (Ranunculus eschscholtzii). Woody, mat forming arctic willow (Salix arctica) often forms high cover in dry turf communities. In more well developed turf communities, forb diversity increase and can reach greater than 40% percent cover. Additional species include arnica (Arnica species), alpine pussytoes (Antennaria species), subalpine wandering daisy (Erigeron peregrinus), one-stem fleabane (Erigeron simplex), sibbaldia (Sibbaldia procumbens), glacier lily (Erythronium grandiflorum), rhexi-leaf paintbrush (Castilleja rhexifolia), western anemone (Anemone occidentalis), alpine Saint John’s wort (Hypericum formosum), elegant death camas (Zigadenus elegans), alpine bistort (Polygonum bistortoides), and viviparous bistort (Polygonum viviparum). Higher levels of organic matter contribute to greater graminoid diversity including purple mountain hairgrass (Deschampsia atropurpurea) and beautiful sedge (Carex spectabilis).

In northwestern Montana, the more mesic expressions of turf communities form on gentle slopes and basins where subirrigation from permanent snow fields and higher levels of organic matter accumulation occur in the soils. Although infrequent, they support additional species including single spike sedge (Carex scirpoidea), curly sedge (Carex ruprestris), hair sedge (Carex capillaris) and Payson’s sedge (Carex paysonis).

In southwestern Montana, the graminoid component of turf includes dunhead sedge, Hayden’s sedge, showy sedge, single spike sedge, spiked woodrush, black and white sedge(Carex albo-nigra), two-tipped sedge (Carex lachenalii), spike sedge (Carex nardina), and Drummond’s rush (Juncus drummondii). Grasses such as alpine blue grass, alpine timothy, alpine fescue, and spike trisetum (Trisetum spicatum) constitute the rest of the graminoid layer. Other common species include blackroot sedge, curly sedge, Parry’s rush (Juncus parryi), Idaho fescue (Festuca idahoenisis), spike fescue (Festuca kingii), and purple reedgrass (Calamagrostis purpurascens) (Cooper et al., 1999).

Southwestern Montana alpine turf communities include additional forb species more common in the middle Rocky Mountain region. Species include alpine forget-me-not (Eritrichium nanum), Ross avens (Geum rossii), common alp lily (Lloydia serotina), and sheep cinquefoil (Potentilla ovina). Fern allies such as lesser spike moss (Selaginella densa) can be common. Moss and lichen cover is typically very low within well developed turf, but is higher in areas with the stoniest soils adjacent to fell fields and scree slopes with late persisting snowfields. Mat forming, woody species such as arctic willow, arctic dryad, snow willow (Salix nivalis), and within the island mountain ranges, bearberry (Arctostaphylos uva-ursi) are usually present within the turf.

Throughout its range in Montana, this system intergrades with scree and talus and alpine fell field communities in areas with decreasing levels of soil development. Turf development can still be evident but is discontinuous due to high rock content and very shallow soil development. In these areas, the turf community intergrades with fellfield species and early colonizers such as arctic dryad (Dryas octopetala), yellow sweetvetch (Hedysarum sulphurescens), shrubby cinquefoil (Dasiphora fruticosa), silver lupine (Lupinus argenteus), crazyweed (Oxytropis species) and milkvetch (Astragalus species). These nitrogen-fixing species accumulate litter within the mats, thus facilitating additional species colonization from the adjacent turf community. Species within the stoniest soils typically include yarrow (Achillea millefolium), penstemon (Penstemon species), phacelia (Phacelia species), alpine fireweed (Chamerion latifolium), explorer’s gentian (Gentiana calycosa), twinflower sandwort (Minuartia obtusiloba), moss campion,alpine goldenrod and aster (Symphyotrichum species). Many of the cushion species are very long lived, well adapted to limited available water during growth and possess a deep, fleshy taproot. These species will persist for decades within the turf as it develops. Early successional graminoids in these areas include Dunhead sedge, Hayden’s sedge, Drummond’s rush, alpine bluegrass, slender wheatgrass, Sandberg’s bluegrass, and spike trisetum. These same species frequently colonize disturbed areas within the turf community such as grizzly bear diggings and ground squirrel burrows.

Imbedded within this system is a mosaic of alpine plant communities that vary in composition depending on soil development, snow retention, subterranean hydrology and localized topography. Snow bed communities dominated by ericaceous dwarf shrubs and willows often occur in as well as alpine wet meadows dominated by tufted hairgrass (Deschampisa cespitosa).

Alpine turf communities are often bordered by subalpine forest krummolz mats and the upper elevational limit of subalpine forests. The most common forest association in Montana is whitebark pine-subalpine fir (Pinus albicaulis-Abies lasiocarpa).In scattered locations on north and east facing aspects, turf communities are bordered by alpine larch(Larix lyallii)forests.