Plants

More than 1,300 plant taxa occur in Yellowstone National Park. The whitebark pine, found in high elevations in the Greater Yellowstone Ecosystem, is an important native species in decline.

NPS/RG Johnsson

 

The plant, or vegetation, communities of Yellowstone National Park include overlapping combinations of species typical of the Rocky Mountains as well as of the Great Plains to the east and the Intermountain region to the west. The exact vegetation community present in any area of the park reflects the consequences of the underlying geology, ongoing climate change, substrates and soils, and disturbances created by fire, floods, landslides, blowdowns, insect infestations, and the arrival of nonnative plants.

Today, the roughly 1,386 native taxa in the park represent the species able to either persist in the area or recolonize after glaciers, lava flows, and other major disturbances. Yellowstone is home to three endemic plant species, at least two of which depend on the unusual habitat created by the park’s thermal features. Most vegetation management in the park is focused on minimizing human-caused impacts on their native plant communities to the extent feasible.

 

Number in Yellowstone

Native plant taxa: more than 1,300:

• Hundreds of wildflowers.
• Trees: nine conifers (lodgepole pine, whitebark pine, Engelmann spruce, white spruce, subalpine fir, Douglas-fir, Rocky Mountain juniper, common juniper, limber pine) and some deciduous species, including quaking aspen and cottonwood.
• Shrubs: include common juniper, sagebrush (many species), Rocky Mountain maple.
• Three endemic species (found only in Yellowstone): Ross's bentgrass, Yellowstone sand verbena, Yellowstone sulfur wild buckwheat.

Nonnative plant species: 225.

Characteristics

• Vegetation in Yellowstone is typical of the Rocky Mountains.
• Elements of the Great Plains and Great Basin floras mix with Rocky Mountain vegetation in the vicinity of Gardiner and Stephen's Creek.
• Hydrothermal areas support unique plant communities and rare species.

Management Issues

• Controlling nonnative species, which threaten native species, especially near developed areas; some are spreading into the backcountry.
• Park partners are monitoring whitebark pine and forest insect pests.
• Biologists survey areas for sensitive or rare vegetation before disturbance such as constructing a new facility.
• Park managers are restoring areas of disturbance.

 

There are several vegetation communities in Yellowstone: higher- and lower-elevation forests and the understory vegetation associated with them, sagebrush-steppe, wetlands, and hydrothermal.

NPS/Yellowstone Spatial Analysis Center

 

Map Key

Green: Lodgepole pine forests

• Dominate more than 80% of the total forested area.
• Can be seral (developing) or climax.
• Climax forests underlain by rhyolite.

Pink: Spruce-fir forests

• Engelmann spruce/subalpine fir dominate older forests.
• Usually found on moist and/or fertile substrates.
• Climax forests underlain by andesitic soils.

Yellow: Whitebark pine forests

• Major overstory component above 8,400 feet.
• Major understory component of lodgepole-dominated forests from 7,000 to 8,400 feet.
• Seeds are ecologically important food for a variety of wildlife species.

Purple: Douglas-fir forests

• Associated with the Lamar, Yellowstone, and Madison River drainages below 7,600 feet
• Often less than 20 inches annual precipitation.
• More frequent historic fire interval (25­­–60 year) than other forest communities in the park.

White: Non-forest

• Includes grasslands, sagebrush, alpine meadows, talus, and hydrothermal environments.
• Encompasses the moisture spectrum from dry sagebrush shrublands to wet alpine meadows.
• Provides the winter and summer forage base for ungulates.

Other communities: Not shown on map

• Aspen—found in small clones interspersed among the sagebrush/forest ecotone (transition zone) along the Yellowstone, Madison, and Snake river drainages.
• Wetland—includes wet meadows, forested wetlands, springs, and seeps comprised of woody vegetation, forbs, rushes, and grasses. Some are thermally influenced.
• Riparian—typically streamside vegetation includes cottonwoods, willows, and various deciduous shrubs.

 

Vegetation Communities

There are several vegetation communities in Yellowstone: higher- and lower-elevation forests and the understory vegetation associated with them, sagebrush-steppe, wetlands, and hydrothermal.

 

 

 

Rare Plants

The Greater Yellowstone region has few endemic plant species, or species that occur only in Yellowstone and nowhere else in the world. Endemic species occur in unusual or specialized habitats such as hydrothermal areas. Within Yellowstone, only three endemic species occur: Ross’s bentgrass (Agrostis rossiae), Yellowstone sand verbena (Abronia ammophila), and Yellowstone sulfur wild buckwheat (Eriogonum umbellatum var. cladophorum).

Several other unusual species live in the Greater Yellowstone Area: warm springs spike rush, which grows in warm water; and Tweedy’s rush, sometimes the only vascular plant growing in acidic hydrothermal areas.

 

 

 

Resources

Craighead, J.J. et al. 1963. A Field Guide to Rocky Mountain Wildflowers from Northern Arizona and New Mexico to British Colombia. Boston: Houghton Mifflin.

Cronquist et al. (ongoing, currently 6 volumes) Intermountain Flora. New York Botanical Garden.

Despain, D. 1990. Yellowstone Vegetation: Consequences of Environment and History in a Natural Setting. Boulder: Roberts Rinehart.

Dorn, B. 2001. Vascular Plants of Wyoming. 3rd edition.

Elliot, C.R. and M.M. Hektner. 2000. Wetland Resources of Yellowstone National Park. YNP: Wyoming. Out of print, available at https://www.nps.gov/yell/learn/nature/upload/wetlandresouces-2.pdf

Hitchcock and Cronquist. 1974. Flora of the Pacific Northwest. Seattle: UWashington Press.

Hitchcock et al. Vascular Plants of the Northwest (5 volumes). Seattle: UWashington Press.

Kershaw et al. 1998. Plants of the Rocky Mountains. Lone Pine Publishing.

Preston, R.J. 1968. Rocky Mountain Trees: A Handbook of the Native Species with Plates and Distribution Maps. New York: Dover.

Romme, W.H. and . Knight. 1982. Landscape diversity: The concept applied to Yellowstone National Park. Bioscience. 32:8.

Shaw, R.J. 1964. Trees and Flowering Shrubs of Yellowstone and Grand Teton national parks. Salt Lake City: Wheelwright Press.

Shaw, R.J. 1992. Wildflowers of Yellowstone and Grand Teton national parks. Salt Lake City: Wheelwright Press.