Our invasive plant ecology and management group studies the impact of invasive and undesired non-native species on rangeland, wildland and mountain plant communities, and the effectiveness of different control strategies (chemical, mechanical, cultural, etc.) to simultaneously control the undesired species while allowing the desired vegetation to increase. We have several different projects and while we are interested in evaluating the impact of all undesired plant species, we are currently concentrating on non-native grasses. Not all non-native and undesired species have a negative impact. Broadly speaking our goal is to assess if the specific undesired and/or non-native species is negatively impacting the system it is growing in - in terms of reducing the growth or presence of other species – and if so, can we effectively reduce it and improve the abundance and richness of the desired vegetation.

Several of our projects concentrate on non-native annual grasses, specifically cheatgrass (Bromus tectorum) and ventenata (Ventenata dubia). These grasses germinate and emerge in the fall and early spring, before our native grasses. This difference in emergence and spring growth gives us a window of opportunity to manage them before the native grasses green-up.

We have three projects focused on annual grass, two are funded by Western Sustainable Agriculture Research and Education (WSARE).

 

WSARE SW24-011

WSARE SW24-011 “Prioritizing effective and sustainable management approaches for cheatgrass and ventenata in Montana rangelands” award (2024-2027). We are evaluating the effectiveness of different control strategies (herbicides, soil amendments, seeding) for invasive annual grasses (cheatgrass and ventenata) and recovery of desired vegetatation. We will make a management decision tool and disseminate our findings in a range of settings.

Our research objectives are:

  1. Quantify the effectiveness of different management strategies to control invasive annual grasses and increase desired vegetation.
  2. Large plot evaluation of the most effective management strategies to reduce invasive annual grasses and increase desired vegetation.
  3. Develop a prioritization and decision framework tool to manage annual invasive grasses and desired vegetation for ecological and economical sustainability.

Oureducationobjectives are:

  1. Develop regular communication with our collaborating producers to ensure information sharing.
  2. Create outreach products, on conditions where cheatgrass and ventenata are most likely to reach high abundance, the efficacy of different management practices to control them, and the prioritization and decision framework tool.
  3. Demonstration of treatments effects.
  4. Dissemination to future producers, managers and the general public.
  5. Publication of research outcomes.

 

WSARE GW24-011

WSARE GW24-011: The research goals the “Evaluating the potential for micronutrient soil amendments to improve rangeland sustainability” award (2024-2025) are to improve our understanding of how the soil amendment NutraFix (boron) impacts seed germination and establishment of both native and non-native grasses as well as how it impacts forage quality of mature forage grasses. Our specific objectives are:

  1. Determine the impact of boron on seed germination of three native species (bluebunch wheatgrass, Idaho fescue and western wheatgrass) and two non-native species (cheatgrass and ventenata).
  2. Determine the impact of boron on seedling establishment of the same five native and non-native species.
  3. Determine the impact of boron on mature native plant species biomass and forage quality grown in a greenhouse.
  4. Determine the impact of NutraFix on,

a) forage quality of the native species and b) soil nutrient availability, four years post application in a field setting.

 

Our project “Cheatgrass and fire: long-term response and best management approaches” funded by the Montana Noxious Weed Trust Fund (2023-2025) evaluates the long-term (10 year) response of cheatgrass to wild and prescribed fire, and the best management approach to manage cheatgrass while increasing desired species. The specific objectives are:

  1. a) Evaluate the long-term response of cheatgrass and community vegetation to prescribed and natural fire, and fire management practices (firebreak);

b) Determine if cheatgrass is spreading from the firebreak into the adjacent unburned and previously burned areas;

c) Quantify the productivity and forage quality of grass and forb vegetation, and soil nutrients and texture, in the burned, unburned and firebreak areas;

  1. Evaluate the long-term response of cheatgrass, forage and all other vegetation to targeted grazing, herbicide and the integration of the two methods along the firebreak;
  2. Determine the most appropriate future weed management approach from Objective 2 along with consideration of the newer herbicide indaziflam, and implement in fall 2023;
  3. Engage with stakeholders who manage invasive annual grasses in Montana rangelands to present our results and discuss management approaches. This will build knowledge and networks through extension engagement.

 

We are also interested in how management practices impact the presence of non-native plant species and the other vegetation.

Conifer encroachment is a concern in many areas of the West, and one question is if undesired species increase as a result of the management and disturbance caused by removal the conifers.  In our study “Monitoring noxious and invasive plant response to conifer control and prioritizing species for integrated management” funded by the Bureau of Land Management (2024-2028) our objectives are:

  1. Monitoring the abundance of plant species across sites that have been managed to control conifer encroachment.
  2. Analyze data to evaluate efficacy of different weed management approaches after prescribed fire for different noxious and invasive species.
  3. Develop set of flowcharts to prioritize noxious and invasive species and the best IWM practices for each species or species groups.
  4. Evaluate the different sampling strategies used, create a protocol for monitoring sites in the future conduct field days and training sessions to extend the results and protocols.

 

Historically, large areas of the environmentally sensitive land in Montana, including older Conservation Reserve Program (CRP) land, was planted to aggressive non-native perennial plant species  (e.g., crested wheatgrass) to reduce soil erosion because they establish from seed more readily than common native species. However, some of these have become near monocultures that are not particularly good for forage nor biodiversity. Our project “Improving plant diversity and function on conservation reserve program land in Montana” funded by the Natural Resources Conservation Service (NRCS) (2024-2028) aims to determine if we can alter the trajectory of these areas to increase useful forage, plant richness and abundance.Our aim is to evaluate the integration of management approaches and seed mixes to improve establishment success and abundance of sown species over time, for both newly established and re-enrolled CRP fields, by:

  1. Quantifying the establishment and survival of the sown species in the different treatments annually.
  2. Monitoring abundance (cover) of all plant species (sown and volunteer) in the different treatments
  3. Quantifying changes in soil carbon, nutrients and biota over time.