National Park Service

Upper Columbia Basin Network (UCBN)

Lemhi Penstemon Monitoring

Lemhi penstemon flowers at Big Hole National Battlefield
Lemhi penstemon flowers at Big Hole National Battlefield

Lemhi Penstemon Monitoring Resource Briefs

Lemhi Penstemon Inventory Reports

Lemhi Penstemon Monitoring Reports

For more information contact: Tom Rodhouse

Parks Monitored

Importance / Issues

  • Lemhi penstemon (Penstemon lemhiensis) is a narrowly distributed endemic found in only 4 counties in Montana and in adjacent Lemhi county in Idaho. Only three populations have been reported to have >300 plants, one of which occurs in Big Hole National Battlefield.
  • Big Hole National Battlefield supports the largest known population of Lemhi penstemon, UCBN monitoring estimates the number of established Lemhi penstemon plants within the Battlefield at approximately 2,500.
  • The species is reportedly in decline due to changes in fire regimes and resulting competition from native and non-native vegetation. Spotted knapweed (Centaurea stoebe) is a threat across the range of Lemhi penstemon, and is increasing within the Battlefield.
  • Monitoring will assist Battlefield management and restoration decision-making by periodically estimating the population sizes and reproductive status of both Lemhi penstemon and spotted knapweed. In addition, monitoring has been designed to specifically provide answers to management-relevant questions about penstemon microsite requirements and penstemon and knapweed response to prescribed fire.

Monitoring Objectives

  • Estimate the population size and determine population trend of established Lemhi penstemon plants within the Howitzer Hill, Horse Pasture, and visitor center subpopulations..
  • Determine the number of basal rosettes per established plant and density of flower stems per established plant as a measure of reproductive vigor.
  • Determine trends in the number of seedlings within intensively monitored plots in each of the three subpopulations.
  • Estimate ground cover in intensively monitored plots in each of the three subpopulations in order to evaluate hypotheses about microsite habitat conditions, competition, and requirements for successful reproduction.
  • Estimate the population size and determine population trend of spotted knapweed plants within the sampling frames of Howitzer Hill and the Horse Pasture.

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Last Updated: April 05, 2017 Contact Webmaster