Title of Oral/Poster Presentation

Influence of Elk Herbivory on Spotted Knapweed Re-invasions in Western Montana

Presenter Information

Olivia SchwandaFollow

Class

Article

Department

Wildland Resources

Faculty Mentor

Michel Kohl

Presentation Type

Poster Presentation

Abstract

Rocky Mountain elk winter range is highly susceptible to invasion by spotted knapweed and other invasive plants. Managers are currently using a variety of techniques including broadcast application of herbicides to reduce knapweed cover. In areas of high elk density, the post-application recovery of native grasses leads to increased grazing pressure by both native (elk) and exotic (cattle) ungulates. Thus, we hypothesized that increased grazing pressure on native plants, and the following release of knapweed is not one of competitive exclusion by knapweed but rather an example of an apparent competition mechanism mediated by ungulate herbivory. Beginning in 2008, large elk/cattle/control exclosures were implemented in the North Hills region of Missoula, MT. In addition, reseeding techniques were implemented in order to examine enemy mediated apparent competition at a fine scale. This project will enter and analyze six years of vegetation status to determine whether elk/cattle herbivory may be influencing the recovery of invasive species in two locations within the North Hills. The primary goal is to determine whether subsequent sampling periods are still needed to further detect a herbivory influence. Secondary goals, included the evaluation of reseeding effectiveness in the recovery of both native and non-native plants. In addition there is potential for undergrad researcher to evaluate differences across grazing species and sites.

Start Date

4-9-2015 9:00 AM

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Apr 9th, 9:00 AM

Influence of Elk Herbivory on Spotted Knapweed Re-invasions in Western Montana

Rocky Mountain elk winter range is highly susceptible to invasion by spotted knapweed and other invasive plants. Managers are currently using a variety of techniques including broadcast application of herbicides to reduce knapweed cover. In areas of high elk density, the post-application recovery of native grasses leads to increased grazing pressure by both native (elk) and exotic (cattle) ungulates. Thus, we hypothesized that increased grazing pressure on native plants, and the following release of knapweed is not one of competitive exclusion by knapweed but rather an example of an apparent competition mechanism mediated by ungulate herbivory. Beginning in 2008, large elk/cattle/control exclosures were implemented in the North Hills region of Missoula, MT. In addition, reseeding techniques were implemented in order to examine enemy mediated apparent competition at a fine scale. This project will enter and analyze six years of vegetation status to determine whether elk/cattle herbivory may be influencing the recovery of invasive species in two locations within the North Hills. The primary goal is to determine whether subsequent sampling periods are still needed to further detect a herbivory influence. Secondary goals, included the evaluation of reseeding effectiveness in the recovery of both native and non-native plants. In addition there is potential for undergrad researcher to evaluate differences across grazing species and sites.