Ecology

Big mountain sagebrush

Species name: Artemisia tridentata

Sagebrush flats are the most dominant community in Jackson Hole, and sagebrush is the most dominant plant in the flats.

Unlike aspen, big mountain sagebrush (the most common species of sagebrush in Jackson Hole) is not capable of asexual reproduction. Sagebrush must reproduce by seeding, and it takes very specific conditions for sagebrush to germinate; however, once sagebrush successfully establishes itself, it is hard for other species to move in and replace it.

Sagebrush, September 19, 2013

Sagebrush, September 19, 2013

Sagebrush adaptations:

Two leaves

Sagebrush has two types of leaves: ephemeral and evergreen. The evergreen leaves allow the plant to photosynthesize throughout the winter while liquid water is available, and the ephemeral leaves allow the plant to maximize photosynthesis while water is most abundant in the spring. When water becomes less available, the plant pulls the resources from the leaves into the twigs and then the leaves fall off in order to reduce water loss through transpiration in the dry months. Both types of leaves have hairs (pubescence) that prevent water loss, protect from ultraviolet rays, and insulate the leaves during the winter.

Sage, Artemesia tridentata, August 28, 2013

Sage, Artemesia tridentata, August 28, 2013

Two roots

Along with two types of leaves, sagebrush has two types of roots. The first type of root is shallow and extends laterally along the surface, and allow the sagebrush to take advantage of high levels of water in the spring. The second type of root is a deep taproot, which allows the sagebrush to absorb water during drought conditions. The taproot can be up to 2 meters long.

Minty fresh

To defend against browsing, sagebrush has evolved terpenes, a chemical defense against herbivory. Terpenes are responsible for the pungent smell and bitter taste of sagebrush leaves. Although the terpenes deter many herbivores, some still rely on sagebrush as a primary food resource such as sage grouse, pronghorn and various insects, including gull midges, agora moths, and mormon crickets.

One thought on “Big mountain sagebrush

  1. Maybe one day we will meet, and I will tell you the story of the day I got my foot caught in a rather large and gnarly sage brush at the base of Lobo Hill. Physics took over and I did an immediate face plant into the vegetation. Megan Barker was there and saw the whole thing, she laughed so hard I think she snorted the previous day’s dinner out her nose.

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