Montana Field Guide

This group is a minor type in MT and contains alkaline and/or saline marshes and wetlands within the Intermountain Region which includes the Bighorn Basin and the Intermountain valleys of southwest Montana. These are intermittently, seasonally or semi-permanently flooded, usually retaining water into the growing season. They are sparsely to densely-vegetated by herbaceous species tolerant of alkaline and/or saline conditions. Typical species include Saltgrass (Distichlis spicata), Alkaligrasses (Puccinellia spp), Foxtail Barley (Hordeum jubatum), Alkali Muhly (Muhlenbergia asperifolia), Alkali Cordgrass (Spartina gracilis), Alkali Sacaton (Sporobolus airoides), Great Basin Wildrye (Elymus cinereus), Beaked Spikerush (Eleocharis rostellata), and Saltmarsh Bulrush (Bolboschoenus maritimus). The presence and abundance of various species and communities depends in large part on the local hydrology and the mix of microhabitats present. Sites occur predominantly along the valley bottoms in closed drainages and/or within depressions, occasionally they can be associated with hot and cold springs.

This Group has no similar Ecological System for the Intermountain Region within Montana.

Saline Wetlands; Marsh, Wet Meadow; Herbaceous Dominated; Intermountain Region; Seasonally or Vernally Saturated; High Clay Contents.

Typical Dominants: Saltgrass (Distichlis spicata), Alkaligrass (Puccinellia spp), Foxtail Barley (Hordeum jubatum), Alkali Muhly (Muhlenbergia asperifolia), Alkali Cordgrass (Spartina gracilis), Alkali Sacaton (Sporobolus airoides), Great Basin Wildrye (Elymus cinereus), Beaked Spikerush (Eleocharis rostellata), Saltmarsh Bulrush (Bolboschoenus maritimus)

This Group occurs primarily in the Intermountain valleys of southwest Montana and in the Bighorn Basin in Carbon County. Minor occurrences extend as far north as the Helena Valley along the Missouri River Drainage. In south-central Montana it is found primarily in the Bighorn Basin of Carbon County and possibly in the vicinity of Gardiner in southern Park County. A geographic outlier with vegetation communities that are likely similar to and best included in this group occurs in the area near the Little Bitterroot River and the Sullivan Creek drainages from near Hot Springs to north of Niarada.

In Montana, G538 occurs in Level IV Ecoregions: 15b (Camas Valley), 17aa (Dry Intermontane Sagebrush Valleys), 17ac (Big Hole), 17 ak (Deer Lodge-Philipsburg-Avon Grassy Intermontane Hills and Valleys), 17w (Townsend Basin) and 18b (Bighorn Basin).

In Montana, G538 occurs or potentially occurs within these Major Land Resource Areas: 32 - Northern Intermountain Desertic Basins, 44A - Northern Rocky Mountain Valleys, 44B - Central Rocky Mountain Valleys, and valley bottoms within 43B - Central Rocky Mountains

Small Patch

This minor type in MT contains alkaline and/or saline marshes and wetlands within the Intermountain Region which includes the Bighorn Basin and the Intermountain valleys of southwest Montana. These are intermittently, seasonally or semi-permanently flooded, usually retaining water into the growing season. They are sparsely to densely vegetated by herbaceous species tolerant of alkaline and/or saline conditions. Sites occur predominantly along the valley bottoms in closed drainages and/or minor within depressions or flats, occasionally they can be associated with hot and cold springs. Rangewide this group is dominated by playas, though we have small areas that are similar to playas in the Great Basin we do not have large, playas typical of the closed basins in that region.

Communities in this group are sparsely to densely-vegetated by herbaceous species tolerant of alkaline and/or saline conditions. Typical species include Saltgrass (Distichlis spicata), Alkaligrass (Puccinellia spp), Foxtail Barley (Hordeum jubatum), Alkali Muhly (Muhlenbergia asperifolia), Alkali Cordgrass (Spartina gracilis), Alkali Sacaton (Sporobolus airoides), Great Basin Wildrye (Elymus cinereus), Beaked Spikerush (Eleocharis rostellata), and Saltmarsh Bulrush (Bolboschoenus maritimus). The presence and abundance of various species and communities depends in large part on the local hydrology, including the soil chemistry and length of soil saturation during the growing season as well as the mix of microhabitats present.

In Montana, this group is represented by 4 Alliances and 8 Associations within the National Vegetation Classification, which likely covers the range of vegetation communities occurring in the group and within the state.

These areas are lined with clay soils, which collect and hold water from rainfall and runoff events. Water evaporates, leaving high salt concentrations in the soils. The presence and abundance of standing water can fluctuate widely from year to year based on precipitation amounts. In areas with standing water or during flood years, some salt-tolerant marsh plant species may grow, such as Cattails (Typha spp.) or Bulrush (Scirpus and/or Schoenoplectus spp.) (Knight 1994).

Information on the management of these communities is lacking at this time.

Information on cestoration considerations for these communities is lacking at this time.

G. Kittel (2015)

S. Mincemoyer

12/5/2024