Montana Field Guide

This group is dominated by a mix of short to tall (generally up to 15ft) riparian shrubs, particularly by various species of willow and alder. It occurs in riparian and wetland areas in the montane and subalpine zones of all the major mountain ranges of the state on both sides of the Continental Divide. It often occurs in a mosaic of herbaceous and shrubby dominated communities with shrub cover in these sites typically ranging from 20%-80%. Common species dominating or co-dominating these communities include
Alders (Alnus incana and Alnus viridis), Water Birch (Betula occidentalis), Red-osier Dogwood (Cornus sericea), Salix spp (Salix barclayi, Salix bebbiana, Salix boothii, Salix brachycarpa, Salix commutata, Salix drummondiana, Salix eastwoodiae, Salix eriocephala (syn S. lutea, S. prolixa), Salix farriae, Salix geyeriana, Salix glauca, Salix lemmonii, Salix melanopsis, Salix planifolia, Salix wolfii), Shrubby Cinquefoil (Dasiphora fruticosa or Potentilla fruticosa), and Silver Sagebrush (Artemisia cana). Sites occur along broad, low gradient streams as well as narrow bands along steeper, gradient streams. They also occur along montane and subalpine springs and seeps, and the margins of lakes and ponds. Stands are often narrow and/or patchy depending on the local topography but may form broad, extensive communities, particularly along low gradient, meandering, subalpine streams. Sites range widely in elevation from a low of about 2,000ft in northwest Montana to approximately 9,000ft in the southern part of the state.

This Group is similar to the Rocky Mountain Subalpine-Montane Riparian Shrubland Ecological System.

Riparian Shrubland; Rocky Mountain Region; Montane and Subalpine Zones; Medium to Tall Shrubs; Floodplains and Streambanks.

Typical Dominants: Alders (Alnus incana and Alnus viridis), Water Birch (Betula occidentalis), Red-osier Dogwood (Cornus sericea), Salix spp (Salix barclayi, Salix bebbiana, Salix boothii, Salix brachycarpa, Salix commutata, Salix drummondiana, Salix eastwoodiae, Salix eriocephala (syn S. lutea, S. prolixa), Salix farriae, Salix geyeriana, Salix glauca, Salix lemmonii, Salix melanopsis, Salix planifolia, Salix wolfii), Shrubby Cinquefoil (Dasiphora fruticosa, Potentilla fruticosa), Silver Sagebrush (Artemisia cana)

This group occurs in riparian and wetland areas in the montane and subalpine zones of all the major mountain ranges of the state on both sides of the Continental Divide. East of the divide, this group occurs in all of the higher elevation island ranges.

In MT, G527 occurs within these Level III Ecoregions: 15 (Northern Rockies), 16 (Idaho Batholith), 17 (Middle Rockies), and 41 (Canadian Rockies).

In Montana, G527 occurs primarily within these Major Land Resource Areas: 43A - Northern Rocky Mountains, 43B - Central Rocky Mountains, and in limited extent within 44A - Northern Rocky Mountain Valleys, 44B - Central Rocky Mountain Valleys, and 46 - Northern and Central Rocky Mountain Foothills.

Small Patch

Sites occur along broad, low gradient streams as well as narrow bands along steeper, gradient streams. They also occur along montane and subalpine springs and seeps, and the margins of lakes, ponds, and peatlands. Stands are often narrow and/or patchy depending on the local topography but may form broad, extensive communities, particularly along low gradient, meandering, subalpine streams. They occur on mineral soils or, if on organic soil, they are only moderately deep (not >30-40 cm). Sites range widely in elevation from a low of about 2,000ft in northwest Montana to approximately 9,000ft in the southern part of the state. In the northwest, they may be found up to about 7,000ft and in southwest and central Montana they are most abundant from about 5,000 to 8,000ft in elevation.

This group is dominated by a mix of short to tall (generally up to 15ft) riparian shrubs, particularly by various species of willow and alder. It often occurs in a mosaic of herbaceous and shrubby dominated communities with shrub cover in these sites typically ranging from 20%-80%. Common species dominating or co-dominating these communities include Alders (Alnus incana and Alnus viridis), Water Birch (Betula occidentalis), Red-osier Dogwood (Cornus sericea), Salix spp (Salix barclayi, Salix bebbiana, Salix boothii, Salix brachycarpa, Salix commutata, Salix drummondiana, Salix eastwoodiae, Salix eriocephala (syn S. lutea, S. prolixa), Salix farriae, Salix geyeriana, Salix glauca, Salix lemmonii, Salix melanopsis, Salix planifolia, Salix wolfii), Shrubby Cinquefoil (Dasiphora fruticosa, Potentilla fruticosa), Silver Sagebrush (Artemisia cana). The herbaceous layer is often dominated by a moderate to dense layer of grasses and sedges. Forbs are often common as well. The composition of the herbaceous layer varies widely by individual communities, topographic setting and geographic area. Individual plant associations should be consulted for species commonly associated with particular communities.

In MT, this group is well-described and represented by 8 Alliances and 47 Associations within the National Vegetation Classification. Some upper subalpine, willow-dominated communities may be undescribed or at least not attributed to MT at this time.

Annual Spring run-off, and heavy rain events during the growing season are important for the establishment and persistence of these communities. Ground water seepage from snowmelt at some sites provides the soil moisture that vegetation depends on for a portion of the growing season when stream flow is low. Beaver activity and the associated increased water table created by damming is crucial to some of these montane, riparian communities.

Grazing along narrow, low order streams results in increased erosion and channel downcutting (Mitsch and Gosellink 2000). Low to moderate elevation sites that are over-browsed often become dominated by Bebb's willow, a shrub that is more resilient to heavy grazing. In sites where there is prolonged disturbance, willow coverage will decrease, and herbaceous vegetation will transition to a grass dominated system including by Kentucky Bluegrass. Fire suppression and timber harvesting in adjacent uplands can affect the succession of riparian communities.

Restoration strategies will vary based on the degree and type of disturbance event. Restoration efforts should concentrate on restoring the stream's hydrology if that has been impacted. Removing grazing from sites will allow the system to recover if not severely impacted, and if there are existing populations of native, herbaceous species (Carex, Juncus, and native grasses) that possess rhizomatous root systems capable of re-colonizing bare soils. However, rhizomatous, exotic grasses such as Kentucky Bluegrass, Common Timothy and Smooth Brome, and pasture forbs such as clovers (Trifolium species) and common dandelion (Taraxacum officinale) will persist on the site and may outcompete existing populations of native graminoids and forbs. In these cases, land managers must decide if the exotic density is sufficiently small such that an adequate stand of native graminoids and forbs can become established on the site from without additional management or control actions. In all cases, grazing by cattle and wildlife should be excluded for several years to allow adequate re-growth and recovery of existing shrubs and the herbaceous understory.

Because all major shrub species within this riparian system are capable of re-sprouting and typically possess extensive, spreading root systems, modified land management practices in areas of low to moderate impact can minimize additional restoration needs. Vigor, health and degree of vegetative regeneration of existing shrubs must be evaluated to determine if these components of the community are capable of recovery in an acceptable time frame. Intensive revegetation efforts should be limited to sites where catastrophic wildfire or prolonged heavy grazing has eliminated existing shrubs and a native seed bank.

G. Kittel (2015)

S. Mincemoyer, C. McIntyre, L. Vance, T. Luna

12/6/2024