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Sagebrush scent identifies species and subspecies

Date: August 24, 2016

Identification of big sagebrush subspecies is difficult, but critical for successful restoration. Researchers discover that volatiles emitted by sagebrush species and subspecies differ in consistent ways and can be used to accurately identify plants


Background

Collecting sagebrush volatiles (odors) in a common garden near Ephraim, Utah.
Collecting sagebrush volatiles (odors) in a common garden near Ephraim, Utah.
Big sagebrush (Artemisia tridentata) is the dominant plant species across much of the Western U.S. and provide critical habitat and food for many endemic species, including the threatened greater sage-grouse. Sagebrush habitat is imperiled due to disturbances and increased wildfire frequency due to exotic annual grasses. 

There is great need for sagebrush habitat restoration, but success rate of restoration efforts is low, sometimes because the right sagebrush subspecies is not used in the right place. Sagebrush subspecies are difficult or impossible to identify and reliable methods of identification are needed.

Research Methods and Results

We collected and analyzed volatile organic compounds (VOCs) emitted from five species and subspecies of sagebrush (Artemisia, subgenus Tridentatae) growing in two common gardens in Idaho and Utah using gas chromatograph and mass spectrometry. We show that the bouquet of VOCs emitted by plants can discriminate closely related species and subspecies of Artemisia, which are difficult to identify using molecular markers or morphology.

Of the 74 total VOCs emitted, only 15 were needed to segregate sagebrush species and subspecies using the random forest classification algorithm with 96% accuracy. All but one of these 15 VOCs showed qualitative differences among taxa. Five VOCs could be used to identify environment (common garden and month), which do not overlap with the 15 VOCs that segregated taxa.

It appears that changes in VOCs either lead the way or follow closely behind speciation in this group. This suggests that VOCs could allow identification of sagebrushes for restoration, helping match the proper plant with the proper habitat.

Key Findings

  • Sagebrushes are famous for their abundant and complex volatile bouquets.

  • We found that the composition of sagebrush volatile bouquets differ reliably among closely related species and subspecies.

  • Only 15 volatile compounds were needed to confidently identify plants, suggesting that plant odor could be used to identify sagebrushes for restoration.

For more information, watch our webinar "The incredible diversity of Sagebrush chemistry and its potential value in restoration":

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Principal Investigators: 
Forest Service Partners: 
Deidre Jaeger, Rocky Mountain Research Station