Progress report for SW24-011
Project Information
Cheatgrass (Bromus tectorum) is a notorious invasive, non-native annual grass, invading large areas of the sagebrush steppe and western rangelands. Ventenata (Ventenata dubia) is a more recent non-native annual grass invader to these ecosystems, is less palatable than cheatgrass and capable of replacing cheatgrass in some areas. Where these invasive annual grasses dominate, they reduce forage production for cattle and habitat quality for wildlife. Restoring highly infested rangeland is both difficult and resource intensive. Targeting areas with low to moderate and patchy levels of infestation could prevent further expansion before the system reaches the no-return tipping point. Similarly, a new strategy “Defend the Core” suggests targeting areas of low-moderate invasive grass invasion because these areas can see the greatest recovery and economic benefit. Much of the northeast region of the sagebrush steppe and other grasslands (e.g., Montana, Wyoming, central-north Idaho) falls into this low to moderate abundance category, and producers in this region are concerned about invasive annual grasses expanding and want help now, before the problem worsens.
Our goal is to develop a prioritization and decision framework tool to help producers select the most appropriate management strategies to control cheatgrass and ventenata and ensure recovery of desired vegetation, to improve the sustainability of their ranches and livelihoods. Because management effectiveness differs according to the degree of invasion, site conditions (e.g., slope, native plant cover) and control strategy used (herbicide, soil amendment, restoration seeding) these factors, along with cost-benefit analysis, will be the basis of the decision tool. The data for this tool will come from current and future studies. We will continue evaluating the effect of integrated weed management strategies to control cheatgrass (WSARE SW20-915) and ventenata (WSARE GW22-237) at our study sites. Our collaborators have suggested we take the best management strategies and apply them on a larger scale than our current plots to further evaluate their effectiveness, at five sites in southwest and west Montana. Because of the interest from our producer collaborators and other ranchers in soil amendments, we have added them to our experimental treatments. At our larger scale study, we will assess not only invasive and desired plant response but also forage quality and soil health.
With this multi-partner, producer-driven project, we will develop a prioritization and decision framework tool that incorporates an economic analysis of trade-offs created by management strategies with landscape and climate attributes for producers, land managers and other interested stakeholders. The whole project team will participate in the research and education objectives, including dissemination of our research results and decision tool using an array of approaches (field days, seminars and presentations at local and regional meetings, web posts, fact sheets, university classes, and scientific manuscripts). Short and longer term adoption will be monitored by our extension specialists. Project outcomes will guide selection of the most effective ecologically and economically sustainable management approaches for invasive annual grasses for our rangelands in southwest and west Montana, the larger northeast region of the sagebrush steppe and northern Great Plains of the American West.
Research Objectives
1) Quantify the effectiveness of different management strategies to control invasive annual grasses (cheatgrass and ventenata) 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.
Education Objectives
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.
Cooperators
- - Producer
- - Producer
- - Producer
- - Producer
- - Producer
Research
Research Objective 1
Strategies we are evaluating to control cheatgrass as part of SW20-915 include a main treatment with herbicide and two novel approaches, and a split treatment of restoration seeding. The three main treatments are, a micronutrient soil amendment (Nutrafix™, Edaphix; 3 rates), mustard seed meal biofumigant (2 rates), and herbicide (Rejuvra®, a.i. indaziflam; 1 rate) plus a no-action control. The main treatment was applied in the fall. A restoration seeding was applied as a split-plot treatment in spring. Four species were sown: Festuca idahoensis, Koeleria macrantha, Nassella viridula, and Pseudoroegneria spicata at the recommended broadcast seeding rate (Pokorny 2020). Treatment placement was fully randomized within each of five replicates/experiment, with 70 plots per experiment (7 main * 2 seed * 5 replicates). Individual plots are 1.25 x 2.5 m. This design has been replicated six times at five sites. Two sites have the full experiment design replicated in both 2020 and 2021; a third site was established in 2020 but the land was sold so another site was established in 2021; thus, we now have two experiments that we established in 2020 and three in 2021.Each summer the ocular canopy cover (percent) has been estimated for all individual species within the central 0.75 m2 of each plot. Above-ground biomass of cheatgrass, other grasses and forbs has been harvested in 0.3 m2 area outside the sampling area, dried and weighed. We will continue this sampling protocol has been repeated since 2021 and will continue through 2025.
We created a similar study (GW22-237) with ventenata as the target species. This study includes three herbicides (Rejuvra®, a.i. indaziflam; Plateau®, a.i. imazapic; and Axiom, a.i. flufenacet and metribuzin) all applied at the recommended rate, and a no-action control as the main treatments, and a split-plot treatment with micronutrient soil amendment (Nutrafix™ Edaphix; 1 rate), fertilizer (NPK; 1 rate) and no fertilizer. Four replicates of each treatment were applied at three sites in fall 2022, with 48 plots per experiment (4 main * 3 nutrient * 4 replicates). Individual plots are 3 x 3 m. Ocular canopy cover has been estimated for all individual species using 2 x 1 m2 frames in each plot during peak vegetation for two seasons, 2023-2024. Biomass was assessed in 2024 at the end of this study.
We are analyzing the response of cover and biomass of, invasive annual grasses, perennial grasses, and forbs. We used linear mixed effects models and analysis of variance (ANOVA) to model the impacts of the effects; main and split management treatments, and interactions. Random effects account for experimental design and repeated measures. We evaluated for model equal variance and linearity assumptions and transformed data as necessary. Dunnett’s tests (DescTools package) are used to compare treatment means to the control means, and Tukey’s HSD tests (multcomp package) are used for multiple comparison tests between sites. All analysis has and will be performed with statistics program R.
Research Objective 2:
We will use the information from RObj1 combined with producer experience and interest to inform our treatment choices. Treatments include soil amendments (1), herbicides (2), herbicide + soil amendment (1), and a no-treatment control, plus restoration seeding as a split-plot treatment. We used Nutrafix™ as the soil amendment because it negatively impacted invasive annual grasses and benefitted perennial species at some of our other sites. Herbicides included Plateau® and Rejuvra® applied at recommended rates, and a combination of Rejurva and Nutrafix. Our split-plot seed treatment mix will be chosen from our current project results and our producer’s preferences. Each treatment plot will be 15 m x 6 m (50’ x 20’), replicated five times (5 main * 2 seeding * 5 replications = 50 plots), at each site. Larger plot sizes will provide more reliable estimates of species responses, biomass production and forage quality, and soil health. We have 5 sites, three cheatgrass and two ventenata (cheatgrass - Fleming, Eichorn and Davis, ventenata - Lane and Weber, despite extensive efforts a third ventenata site was not possible generally because high county agent engagement with landowners has lead to active control Ventenata so most sites had been very recently controlled). Sites were established in late summer/fall of 2024.
We had intended to assess another soil amendment, Rhyzogreen®, RioGen, in this study but between writing the proposal and setting up the field experiment it became apparent that the interest in the product has waned - but interest in combining Rejurva and Nutrafix had increased so we used the latter combination in our main experiment. We are, however, conducting a greenhouse experiment with Rhyzogreen and if results are encouraging will conduct a small field study.
We will assess plant abundance and biomass of (a) invasive annual grasses and (b) other established species and (c) count the number of grass seedlings, within each treatment plot with 6 x 0.5 m2 quadrats at peak vegetation each summer from 2025-2027. (d) Nutrient quality (crude protein, digestibility, digestible nutrients and fiber) of the dominant forage species and invasive annual grasses will be assessed within each treatment/site to evaluate differences in forage quality.
Further we will measure traits that contribute to soil health, including changes to soil macro- and micro-nutrients and organic matter within the main management treatments. Soil health measures are diverse, including measures of physical, chemical and biological traits of soil systems (NRCS 2019). We will focus on traits associated with nutrient cycling and soil moisture retention. We will assess (e) soil enzyme activity for 5 enzymes associated with nitrogen, phosphorus, carbon and sulphur cycling, (f) potentially mineralizable nitrogen (PMN), (g) soil organic matter (SOM), (h) total organic carbon (TOC), and (i) labile carbon, in each treatment and site. Sampling will be performed early in the growing season by compositing 7 x 2.5 cm (1") diameter by 10 cm (6”) depth cores from each plot. Soil enzymes are a catalyst for nutrient cycling and an indication of microbial activity and nutrient dynamics. Potentially mineralizable nitrogen provides a measure of the microbial activity that makes N available from SOM, and provides an estimate of the N available for plant-uptake throughout the growing season. Total organic carbon will be measured on a combustion analyzer, and labile carbon, the portion of carbon most reactive to management changes, will be assessed from the reaction of potassium permanganate, KMnO4 (Weil et al. 2003).
The vegetation and forage quality data, along with soil health measures, will be assessed using the same statistical approaches as described in RObj1.
Research Objective 3
Species distribution modelling (SDM) helps us understand which abiotic, climate and biotic conditions are most suitable for a species to grow. Plants growing in more suitable habitats may grow better, producing more biomass, and compete more with other species, but they may also respond better to management than those growing in less suitable areas. For example, fast growing plants will absorb herbicide more effectively than stressed, slow growing ones. Conversely, highly overlapping plants can cause the management strategy to work less well (Wauchope and Street 1987). Risks of negative impact by weeds will also be higher where those weeds are more likely abundant. Therefore, we will use our small- and large-plot data to evaluate weed impacts using (a) SDM alone and (b) with the addition of management efficacy data (see Giljohann et al. 2011), for more site-specific management prioritization. At the most simplistic level SDM can provide information on the conditions where cheatgrass and ventenata are likely to occur. The occurrence will also depend upon climate, elevation, soil type, and the surrounding plant communities. Publicly-available occurrence data can be used to model coarse effects of climate and topography on weed risks. The data gathered in RObj1-2 will add fine-scale data that will help us produce refined and more detailed risk models of these species. We will also be able to go beyond modeling where these weeds can be and demonstrate how their impacts and responses to management vary depending upon site conditions. Being able to combine where a species is likely to be at higher abundance, have a greater risk of negative impacts, and be more responsive to management will help identify current and future threats and is one step in creating effective decision frameworks. We have begun this objective by collating data for cheatgrass and ventenata.
(c) Management decisions have complex trade-offs. Not treating invasive annual grasses may be cost-saving in the short-term but not if they increase in the longer term. Management strategies may reduce prevalence of invasive grasses but can be costly or negatively impact the desirable species and forage availability and quality. We will calculate the economic trade-offs (associated costs and benefits) of invasive annual grass management approaches and estimate a cost/benefit ratio and the long-term net present value of each of the management practices for a ranching operation, using our study data. The major inputs in this analysis will be the costs associated with the management strategies, cheatgrass and ventenata biomass, and availability and quality of forage for livestock.
To estimate the economic impacts of management, management costs, livestock supplementation requirements, alternative feed prices, and forage production data will be combined with regional cow-calf operation enterprise budgets for Major Land Resource Areas developed by University of Wyoming Extension (2019). Partial budgets will be created to assess the impact of management actions and invasive grasses on ranch income and production costs. Cost of management will be determined using a combination of market data, regional enterprise budgets, and through personal communications with researchers and producers. To determine annual grass abundance and forage availability, species abundance from RObj1-2 will be pooled into functional groups: invasive annual grasses, perennial grasses, perennial forbs, and annual forbs. Site vegetation abundance will be used to estimate the annual production of forage in terms of animal unit months (AUMs) for the entire pasture or ranch for each year of data collection. We will evaluate the long-term economic impacts to a ranch that sustains losses to forage quantity or quality from annual grass invasion and management choices under various response (destocking, supplemental feeding) and invasive grass management costs. We will test forage utilization levels (e.g., 25%, 35%, 50%) of total measured available forage from RObj2 to then calculate supplemental feed requirements and cost. Cost-benefit ratios and net present value for each management scenario will be calculated using the annual costs and benefits. Both will be calculated using a range of discount rates, which represents variation in ranchers’ time value of money.
(d) Finally, we will create an invasive annual grass management decision framework tool that incorporates information above to quantify ecological and financial risks and rewards of cheatgrass and ventenata management. This will be generated as a stepwise decision framework that will not require parameterization by the producer, just a knowledge of their land and their goals – for example increased forage production or production combined with increased biodiversity. Herbicide is the most common approach for invasive annual grass management but does not generally provide a long-term solution, but integrating other management approaches can help the longevity of the control and shift to a more desired rangeland community. Furthermore, the tool will allow ranchers to prioritize portions of their ranch for management – similar to the Defend the Core philosophy - and be more site-specific or tailored in their management of these specific areas.
Research Objective 1
Cheatgrass
Statistical methods:
To test the effects of our treatments on the cover of cheatgrass, perennial grasses, and forbs we performed linear mixed effects models. Fixed effects included an interaction between management treatment (control, MSM, NutraFix, or Rejuvra) and year post treatment (1-4), and a restoration seeding split treatment. A random effect of site and plot ID was included to account for the split plot design and repeated measures. Analysis of variance (ANOVA) and the emmeans package were used to compare means across and between treatments. Assessment of diagnostic plots revealed violations of the linearity and equal variance assumptions, so natural log transformations were performed on all responses, but results are reported on the original scale.
Cheatgrass results:
The restoration seeding addition did not impact cheatgrass cover (p = 0.158). There was an interaction between treatment and year post application (p<0.001) indicating that the impacts of treatment on cheatgrass cover changed over time. The first-year post application, all treatments except the low mustard reduced cheatgrass cover relative to the non-treated controls (all p<0.030; Fig. 1). The second-year post treatment, only the NutraFix (all p<0.045) and Rejuvra (p<0.001) treatments had cheatgrass covers lower than the control plots (Fig. 1). The third year, only the low Nutrafix (p = 0.042) and Rejuvra (p<0.001) plots had lower cheatgrass cover (Fig. 1). And by year four no treatments had cheatgrass cover lower than the non-treated controls (all p>0.240; Fig. 1).
Perennial grass cover did not differ between plots that received restoration seeding or not (p = 0.397). There was an interaction between treatment and year post application (p<0.001) indicating that the impacts of treatment on perennial grass cover changed over time. The first three years post application, there was weak evidence that Rejuvra plots had higher cover of perennial grasses than non-treated controls (p = 0.099, p = 0.072, p = 0.081; Fig. 2) but there was no difference by the fourth. In contrast, the fourth year post treatment, the high mustard plots had lower cover of perennial grasses than the non-treated controls (p =0.058; Fig. 2).
The restoration seeding addition did not impact forb cover (p = 0.654). There was an interaction between treatment and year post application (p<0.001) indicating that the impacts of treatment on forb cover changed over time. Forb cover was lower in Rejuvra plots than the non-treated controls the first-year post application (p = 0.042). In years 2-4 forb cover was lower in Rejuvra plots (p = 0.001, p = 0.035, p = 0.006; Fig. 3).
Ventenata
Statistical methods:
Cover and biomass of ventenata and perennial grasses were evaluated (response variables) to determine how each were affected by herbicide and fertilizer treatment (fixed variables), with site as a random effect. We used generalized linear models with Gaussian distributions, and ANOVA to determine statistical differences. A post-hoc Tukey HSD test was used to examine pairwise differences between the treatments. Data were evaluated for model assumptions of heteroscedasticity, normality, and constant variance, where all models required log transformation.
Ventenata results:
The cover of ventenata in the non-sprayed control treatment did not change over time (p > 0.10). Ventenata cover decreased from before treatment (2022) to first year post-treatment (2023) for all herbicides (p < 0.01) and within 2023 all herbicides had lower cover than the control (p < 0.01 all; Figure 4 a&b). However, in the second season (2024), Axiom did not differ from the Control (p = 0.99), while the Rejuvra and Rejuvra + Plateau treatments were lower (p < 0.01; Figure 4 c&d). The fertilizer treatments had no effect on ventenata cover (p = 0.19) and did not demonstrate an interaction with year (p = 0.24) or with herbicide (p = 0.40). In the second-year post treatment (2024) ventenata biomass was not impacted by any fertilizer treatment (p = 0.51) nor an interaction between fertilizer and herbicide (p = 0.13).
Biomass did not differ between the Control and Axiom treatments (p = 0.07) but was lower in the Rejuvra (p < 0.01) and Rejuvra + Plateau (p < 0.01) treatments relative to the Control (Figure 5).
Perennial grass cover was not impacted by fertilizer treatment (p = 0.11), herbicide treatment (p = 0.92), nor year post treatment (p = 0.90; Figure 6). Similarly, perennial grass biomass did not differ from fertilizer treatment (p = 0.47) nor herbicide treatment (p = 0.96; Figure 7).
Forb percent cover was impacted by herbicide (p = 0.06), as well as the interaction between fertilizer and year (p = 0.02), though there were no pairwise differences in fertilizer and year detected (p > 0.56). Within 2023, when controlling for fertilizer treatment, forb percent cover was highest in the Axiom treatment (mean cover 11%) though it did not differ statistically from the control (mean cover 6%; p = 0.99) or Rejuvra (mean cover 2%; p = 0.36), however there was strong evidence that forb cover was greater than in the Rejuvra + Plateau treatment (mean cover <1%; p < 0.01). All treatments increased in forb cover from 2023-2034 (p = 0.01, all), where increases averaged 38% (Figure 8). There was no evidence of a change in forb biomass given fertilizer treatment (p = 0.65) nor herbicide (p = 0.09).
Research Objective 2
We have 5 sites, three cheatgrass and two ventenata (cheatgrass - Fleming, Eichorn and Davis, ventenata - Lane and Weber). Sites were established and treatments installed in late summer/fall of 2024. We will start collecting data at these sites in summer 2025. Despite extensive efforts a third ventenata site was not possible because of very high engagement between county agents and landowners, leading to active control of ventenata with Rejurva, such that there are no known sites we can work on.
We had intended to assess another soil amendment, Rhyzogreen®, RioGen, in this study but between writing the proposal and setting up the field experiment it became apparent that producer interest in the product had waned - but interest in combining Rejurva and Nutrafix had increased, so we used the latter combination in our main experiment. We are, however, conducting a greenhouse experiment with Rhyzogreen and if results are encouraging will conduct a small field study.
Research Objective 3
a-b) We have been collecting data and determining methods needed to follow a two-step modeling approach. In the first modeling step, we are creating high-resolution site-specific models of cheatgrass and ventenata abundance that we can use to develop economic decision models, informed by the data collected in Objectives 1 and 2. In the second modeling step, we will model the regional distribution of cheatgrass and ventenata to identify areas of high potential management impacts.
To gather data for step one, we collected vegetation data at approximately 31 sites at Red Bluff Research Ranch (Norris, MT). Specifically, we have 500 plots from these 31 sites, (10 sites and 60 plots in 2024; 21 sites and 440 plots in 2023). (The 2023 data were collected as part of a project supported by the Montana State College of Agriculture Mini-grant Program.) We have a further 100 plots from around the state. Together these data span a variety of locations and possible habitats and will be used to create a Red Bluff-specific cheatgrass distribution and abundance model. A similar model will be constructed using cheatgrass data from Yellowstone National Park collected from 2001–2007 by PI Rew. Modeling efforts will begin in the summer and fall, following a final data collection in the early summer of 2025. Ventenata is not present at Red Bluff, so we have been in communication with the Montana Spatial Analysis Lab (PI, Jessica Mitchell) to collaborate. They have detailed ventenata and cheatgrass models at several locations throughout the state. Acquiring a high-resolution site-specific ventenata model is not necessary to satisfy our stated objectives but it is desirable. As of January 2025, we have detailed cheatgrass distribution and abundance data from two sites and are working with collaborators to access ventenata and cheatgrass data at several other sites.
For step two, publicly-submitted occurrence data (e.g. from GBIF.org and EDDMapS.org) will be used to construct region-wide coarse-scale species distribution models. These data are freely available and do not require special permissions to access. We will access the most current-possible data when we transition from field data collection to modeling in the fall of 2025.
c) A comprehensive review of peer-reviewed publications and technical reports addressing management practices for cheatgrass and ventenata was conducted. The review focused on identifying best application practices, frequency of treatment, potential ecological side effects, and reported costs where available. This synthesis will inform the range of practices to be included in the economic analysis.
We also began compiling data on cost of invasive grass control measures. We contacted and received data from state and federal agencies that conduct weed management in Idaho (BLM, USFS, and Idaho State Department of Agriculture). Data collected include per-acre costs for mechanical, chemical, and integrated treatment strategies, as well as labor and application costs. These region-specific figures will improve the accuracy of our cost modeling.
We collected forage price and quality data from USDA sources, state-level agricultural reports, and livestock producer networks in Idaho and Montana. These data reflect the market value of forage and will be used to estimate the economic impact of forage loss (or gain) under different invasive grass management scenarios.
(d) Finally, we will create an invasive annual grass management decision framework tool that incorporates information above to quantify ecological and financial risks and rewards of cheatgrass and ventenata management. This aspect of the project will not be started until year two-three.
Research Outcomes
Research Objective 1
The results of the first 3-4 years of the cheatgrass study have been analyzed for their impact on the target and desired species, as well as impact to the whole plant community. We have one more year of data collection but the preliminary analysis suggests that cheatgrass can be effectively controlled by all our treatments but for differing amounts of time with herbicide (Rejurva) having the longest control followed by soil amendment and mustard seed meal, though there was site variability. All treatments impacted the productivity and occurrence of species in the first year, but this didn't necessarily last info future seasons. However, our results suggest that mustard seed meal is not an ideal strategy. The soil amendment Nutrafix is being promoted as a means to improve native and desired grass while limiting or reducing the growth of non-native annual grasses. Our results have some variability and another year of data will be helpful, but overall this approach needs further evaluation over a range of sites but looks promising.
We have presented the results of this study at one to two regional meetings each year for last few years. And presented at field days.
As we are in the first year of research objectives 2 and 3 we have no results to report at this time.
Education and Outreach
Participation Summary:
Education Obj1) Develop regular communication with our collaborating producers to ensure information sharing.
Conduct semi-annual updates and project meetings with all cooperators to maintain high levels of interaction and feedback on research and outreach progress. The first meeting will be November 2024, and every 6 months after (i.e., May 2025, November 2025, May 2026, November 2026, April 2027). Meetings will be organized to include a review of the main objectives, a summary of what has been completed to date, and specific discussion points designed to encourage high levels of input from our producers. These will be conducted virtually. (Target: team members only)
Education Obj2) 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.
Outreach materials during Year 1 will include an overview of our questions and study design, published on our websites (https://www.montana.edu/extension/invasiveplants/; https://www.montana.edu/plantinvasions/), so that cooperators and general public have a place to access information. Materials produced in years two and three will include a summary of results, as described below.
Results from Research objectives 1-3 will be used to develop outreach products including:
(a) Extension fact sheets will be available in print and digital format. (Target: producers and stakeholders, interested public.) We will produce at least one fact sheet from our research objectives, and we will aim to have them completed within 6 months of completing the research. These products will highlight results from our research and translate those results into management implications. Fact sheets will be shared in-person through events that principal investigators regularly attend and are invited to because of this project; through listservs like Dr. Mangold’s Monthly Weed Post; and incorporated into a regional technology transfer program for invasive annual grasses that Dr. Mangold is participating in with colleagues from Wyoming and the greater western region of the country. We estimate reaching ~5,000 producers and interested stakeholders with these fact sheets.
(b) Seminars will be conducted in coordination with county and reservation extension agents, county weed districts and local resource managers. (Target: producers and interested public.) We will integrate knowledge learned from this project into at least 20 seminars delivered across Montana reaching ~2,000 producers and interested stakeholders. Because we will be presenting our work within reservations and other rural areas of the state, we will be targeting some historically underserved communities. A likely seminar venue will be the MSU Extension Pest Management Tour which occurs in a different region of the state each October (southwest in 2024, northcentral in 2025, east in 2026). The Pest Management Tour typically reaches 200 to 250 people in 6 to 10 communities within the region where the tour occurs. For the 2024 tour, communities will likely include (based upon previous years’ tours) Dillon, Whitehall, Townsend, Bozeman, Butte, and Livingston. These are all communities where invasive annual grasses are problematic and some of our research sites are nearby. For the northcentral tour in 2025, a likely community will be Cascade or Great Falls, another community where our research is occurring.
The Montana Weed Control Association (MWCA) spring and fall weed coordinator training is another venue where we can share the knowledge learned through this project. Spring and fall training typically attract county weed coordinators, state and federal invasive species coordinators, and commercial applicators, many of which advise or contract weed control activities on private lands. Likely dates include April and October 2025 and 2026, and April 2027, and locations typically include one in eastern Montana and one in western Montana.
(c) Presentations at state (e.g., Montana Weed Control Association annual conference, Western Montana Grazing and Ag Conference) and regional (e.g., Society of Range Management, Western Society of Weed Science) conferences. (Target: producers, land managers, researchers.) These conferences each draw 200 to 1600 attendees including producers, educators, public land managers, policy makers, and researchers. The MWCA annual conference is typically held in late January to early February in a central location in Montana (e.g., Great Falls, Helena, or Billings). We are often asked to organize and moderate a research strand, and invasive annual grass management has been of great interest to the audience in recent years. With that in mind, we can incorporate the research proposed here into a strand in 2025-2027. The Western Montana Grazing and Ag Conference is typically held in January, most often in Missoula. Drs. Rew and Mangold typically attend and present papers at these meetings, and results from this project can be incorporated into their efforts at these meetings. At the regional level we (Rew, Mangold, Lee) will attend the Western Weed Science Society (WSWS) and the Society of Range Management (SRM), both are held annually in spring. More weed orientated information will be presented at the WSWS. At the SRM we will present all aspects of the study, including the economic and decision tool findings, to directly engage practitioners, land managers, and policy makers. Moreover, we will actively seek networking opportunities to build crucial relationships with influential figures in the field and extend our outreach. These meetings also serve as a venue for their graduate students to present their research, gaining important science communication skills for advancing their careers in invasive plant research and management.
Education Objective 3) Demonstration of treatments effects
Field tours and tailgate meetings at both cheatgrass and ventenata research sites will be held in the second and third summer seasons (2025-2026). (Target: producers, stakeholders and interested public). We will hold field tours and tailgate meetings each of these seasons, ideally with 30 to 50 attendees at each event. Ideal timing for these field tours will be June through late July, and we will work with our cooperators and other local stakeholders (e.g., extension agents and weed coordinators) to determine the best dates based upon competing events in the area. We will aim to spread these events spatially across our sites in southwest and west Montana to provide better access to our audiences. One of our project sites may be used as a location for the larger regional technology transfer program mentioned above, which also aims to hold field tours and demonstrations on an annual basis. We will start these tours with lunch, from experience (our and others) having refreshments first allows participants to interact with presenters and each other initially which improves communication and participation throughout the rest of the day.
Our producers will showcase the larger research plots on their ranches (RObj2) to their neighbors on an ad-hoc basis. Demonstrating the results in this low-key neighborly way is another way to increase adoption.
Education Objective 4) Dissemination to future producers, managers and the general public
Results of this work will be presented annually - starting in fall 2024 - and in perpetuity in the university courses we teach: plants and their environment (ENSC210, 70 students, spring semesters), biodiversity and field sampling and monitoring (ENSC410, LRES510, 30 students, fall semesters), restoration ecology (ENSC461, 60 students, fall semesters), seminar (LRES594 10 students, spring and fall semesters), natural resource ecology (NRSM240, 90 students, fall semesters), and habitat inventory and analysis (NRSM453, 30 students, fall semesters) at MSU. At University of Idaho, Lee will use the results of this work in advanced natural resource economics (Ag Econ 532, 10 students, spring semesters). This will reach students who will graduate and work as producers, for agencies or consulting firms, or in other professions to create better understanding and dissemination of improved approaches to manage invasive annual grasses and ranch more sustainably.
Education Objective 5) Publication of research outcomes
We will publish our research in reputable journals to reach a wider audience and collaborate with key organizations and agencies to advocate for the adoption of our research recommendations, thus bridging the gap between scientific findings and tangible impacts on range management. We aim to submit several research manuscripts (3-5) to journals such as, Rangeland Ecology and Management, Invasive Plant Science and Management, and Western Economics Forum. Manuscripts will be submitted in the second and third year of the project.
Education Obj1) Develop regular communication with our collaborating producers to ensure information sharing.
On October 24, 2024, we met with two cooperators (Edaphix and AMB West) to discuss progress on our project through summer and early fall. We also discussed preliminary plans for sampling research plots on AMB West properties in summer 2025. We will schedule a spring update meeting with everyone for May 2025.
Education Obj2) 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.
During mid-October 2024, a seminar on invasive annual grass identification and management was delivered at two locations (Deer Lodge, Bozeman) in southwest Montana during the annual Pest Management Tour. Sixty-six people participated for a total of 66 contact hours. The audience was comprised of mostly agricultural producers, but county extension agents, weed district personnel, and resource managers were also represented. A post-seminar survey showed a 28% increase in knowledge, with audience ratings of their knowledge of the topic increasing from 3.3 to 4.3 (1 = no knowledge, 2 = very low knowledge, 3 = low knowledge, 4 = high knowledge, 5 = very high knowledge) because of attending.
(b) Additional seminars were held as well. In September 2024, a webinar was delivered during the all-state meeting of personnel from the Natural Resources Conservation Service (NRCS). This webinar focused on results of invasive annual grass research conducted in Montana and was attended by about 50 people (50 contact hours). Another presentation included a 10-minute overview of ventenata at the Montana Invasive Species Council (MISC) Invasive Species Summit in November 2024. Ventenata has been identified as one of the top priority species in Montana. Approximately 100 people attended including government organizations, non-governmental organizations, MSU Extension personnel, weed districts, conservation districts, and resource managers from Canadian provinces (about 17 contact hours). Also in November, a seminar was delivered to agricultural producers in Medora, ND. This seminar was a special invitation from the local weed boards and focused on ventenata, a species North Dakota is concerned about and looking for research-based information to help them prepare. The seminar was attended by 185 people (185 contact hours).
During January 6-10, 2025, a presentation that included ventenata as a new noxious weed invader in central Montana (e.g., Cascade County where one of our research sites is located) was shared with nine audiences during the MSU Extension Cropping Series Tour. A total of 278 people (278 contact hours) were reached including agricultural producers and extension and county weed district personnel.
Finally, a Weed Post will come out in April 2025 titled “Integrated management of ventenata infested rangelands using herbicides and fertilizers, and the response of perennial grasses.”
(c) PhD candidates Erin Teichroew and Lilly Sencenbaugh have given three presentations since the inception of this grant. Teichroew presented at the MWCA in January 2025 where the attendance was approximately 230 people. Her talk was of great interest to the U.S. Forest Service Region 1 vegetation managers who instigated a follow up conversation because they were looking for research-based guidance on the efficacy of soil amendments for managing invasive annual grasses and we shared the presentation with them. Both candidates presented at the Biennial Scientific Conference on the GYE in September 2024, with approximately 300 people in attendance.
Teichroew EB, Sencenbaugh L, Mangold JM and Rew LJ (2025) Novel cheatgrass and native grass management. Montana Weed Control Association Annual Meeting, Great Falls, January 28-30, 2025.
Sencenbaugh L, Mangold J and Rew LJ (2024) Competitive dynamics of two non-native grasses, cheatgrass (Bromus tectorum) and ventenata (Ventenata dubia), and cause for concern of secondary invasion in the Greater Yellowstone Ecosystem. 2024 Biennial Scientific Conference on the GYE, Big Sky, MT, September 3-5, 2024.
Teichroew E, Maxwell B and Rew LJ (2024) Are native perennial grasses slowing the invasion of cheatgrass in the Greater Yellowstone Ecosystem. 2024 Biennial Scientific Conference on the GYE, Big Sky, MT, September 3-5, 2024.
Education Objective 3) Demonstration of treatments effects
Nothing at this time
Education Objective 4) Dissemination to future producers, managers and the general public
Lectures on revegetation were shared with students in restoration ecology (ENSC461), weed ecology and management (ENSC443), and land resources and environmental sciences (ENSC110) at Montana State University in November 2024. These lectures focused on challenges associated with revegetating invasive annual grass-infested areas and key ecological principles serving the basis for our research objectives. Approximately 135 students participated.
A module was presented to 30 students enrolled in environmental economics (AGEC451) at the University of Idaho, in which students applied economic principles and non-market valuation to real-world land management decisions related controlling invasive annual grasses.
Education Objective 5) Publication of research outcomes
Three studies that were completed during the previous WSARE grant have been submitted to journals for publication. One, led by Teichroew evaluates the use of seed pellets is published. Another evaluates the response of cheatgrass and other vegetation to herbicide is under review, this was led by Dr. Mumford. Finally, Teichroew has submitted a manuscript on the results of the first three years of Objective 1.
Teichroew E and Rew LJ (2024) Comparing the composition of seed pellets to aid in semi-arid restoration seedling recruitment. Restoration Ecology, (On-line 11/19/24). Open access. https://doi.org/10.1111/rec.14349
Sencenbaugh L, Mangold J, Ulrich D and Rew LJ (2024). Efficacy of multiple Brassica biofumigation techniques in the suppression of non-native and native grass seedling emergence and productivity Weed Research. (Submitted May 20, 2024, Accepted 11/4/2024, online 11/17/24) Open access. https://doi.org/10.1111/wre.12670
Mumford C, Mangold J, Winnie J, Cutting K, Zabinski C and Rew LJ (submitted May, 2024, under revision, 12/31/24 minor revision, accepted, 2/27/25). Response of low-abundance cheatgrass and other vegetation to two consecutive herbicide treatments in high-elevation sagebrush steppe. Rangeland and Ecological Management.
Teichroew E, Mangold J, Sencenbaugh L and Rew LJ (submitted 4/1/2025) Novel approaches to invasive grass management: assessing efficacy and impacts on plant diversity. Applied Vegetation Science.
Education and Outreach Outcomes
Education Obj1) Develop regular communication with our collaborating producers to ensure information sharing.
On October 24, 2024, we met with two cooperators (Edaphix and AMB West) to discuss progress on our project through summer and early fall. We also discussed preliminary plans for sampling research plots on AMB West properties in summer 2025. We will schedule a spring update meeting with everyone for May 2025.
Education Obj2) 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.
During mid-October 2024, a seminar on invasive annual grass identification and management was delivered at two locations (Deer Lodge, Bozeman) in southwest Montana during the annual Pest Management Tour. Sixty-six people participated for a total of 66 contact hours. The audience was comprised of mostly agricultural producers, but county extension agents, weed district personnel, and resource managers were also represented. A post-seminar survey showed a 28% increase in knowledge, with audience ratings of their knowledge of the topic increasing from 3.3 to 4.3 (1 = no knowledge, 2 = very low knowledge, 3 = low knowledge, 4 = high knowledge, 5 = very high knowledge) because of attending.
(b) Additional seminars were held as well. In September 2024, a webinar was delivered during the all-state meeting of personnel from the Natural Resources Conservation Service (NRCS). This webinar focused on results of invasive annual grass research conducted in Montana and was attended by about 50 people (50 contact hours). Another presentation included a 10-minute overview of ventenata at the Montana Invasive Species Council (MISC) Invasive Species Summit in November 2024. Ventenata has been identified as one of the top priority species in Montana. Approximately 100 people attended including government organizations, non-governmental organizations, MSU Extension personnel, weed districts, conservation districts, and resource managers from Canadian provinces (about 17 contact hours). Also in November, a seminar was delivered to agricultural producers in Medora, ND. This seminar was a special invitation from the local weed boards and focused on ventenata, a species North Dakota is concerned about and looking for research-based information to help them prepare. The seminar was attended by 185 people (185 contact hours).
During January 6-10, 2025, a presentation that included ventenata as a new noxious weed invader in central Montana (e.g., Cascade County where one of our research sites is located) was shared with nine audiences during the MSU Extension Cropping Series Tour. A total of 278 people (278 contact hours) were reached including agricultural producers and extension and county weed district personnel.
Finally, a Weed Post will come out in April 2025 titled “Integrated management of ventenata infested rangelands using herbicides and fertilizers, and the response of perennial grasses.”
(c) PhD candidates Erin Teichroew and Lilly Sencenbaugh have given three presentations since the inception of this grant. Teichroew presented at the MWCA in January 2025 where the attendance was approximately 230 people. Her talk was of great interest to the U.S. Forest Service Region 1 vegetation managers who instigated a follow up conversation because they were looking for research-based guidance on the efficacy of soil amendments for managing invasive annual grasses and we shared the presentation with them. Both candidates presented at the Biennial Scientific Conference on the GYE in September 2024, with approximately 300 people in attendance.
Teichroew EB, Sencenbaugh L, Mangold JM and Rew LJ (2025) Novel cheatgrass and native grass management. Montana Weed Control Association Annual Meeting, Great Falls, January 28-30, 2025.
Sencenbaugh L, Mangold J and Rew LJ (2024) Competitive dynamics of two non-native grasses, cheatgrass (Bromus tectorum) and ventenata (Ventenata dubia), and cause for concern of secondary invasion in the Greater Yellowstone Ecosystem. 2024 Biennial Scientific Conference on the GYE, Big Sky, MT, September 3-5, 2024.
Teichroew E, Maxwell B and Rew LJ (2024) Are native perennial grasses slowing the invasion of cheatgrass in the Greater Yellowstone Ecosystem. 2024 Biennial Scientific Conference on the GYE, Big Sky, MT, September 3-5, 2024.
Education Objective 3) Demonstration of treatments effects
Nothing at this time
Education Objective 4) Dissemination to future producers, managers and the general public
Lectures on revegetation were shared with students in restoration ecology (ENSC461), weed ecology and management (ENSC443), and land resources and environmental sciences (ENSC110) at Montana State University in November 2024. These lectures focused on challenges associated with revegetating invasive annual grass-infested areas and key ecological principles serving the basis for our research objectives. Approximately 135 students participated.
A module was presented to 30 students enrolled in environmental economics (AGEC451) at the University of Idaho, in which students applied economic principles and non-market valuation to real-world land management decisions related controlling invasive annual grasses.
Education Objective 5) Publication of research outcomes
Three studies that were completed during the previous WSARE grant have been submitted to journals for publication. One, led by Teichroew evaluates the use of seed pellets is published. Another evaluates the response of cheatgrass and other vegetation to herbicide is under review, this was led by Dr. Mumford. Finally, Teichroew has submitted a manuscript on the results of the first three years of Objective 1.
Teichroew E and Rew LJ (2024) Comparing the composition of seed pellets to aid in semi-arid restoration seedling recruitment. Restoration Ecology, (On-line 11/19/24). Open access. https://doi.org/10.1111/rec.14349
Mumford C, Mangold J, Winnie J, Cutting K, Zabinski C and Rew LJ (submitted May, 2024, under revision, 12/31/24 minor revision, accepted, 2/27/25). Response of low-abundance cheatgrass and other vegetation to two consecutive herbicide treatments in high-elevation sagebrush steppe. Rangeland and Ecological Management.
Teichroew E, Mangold J, Sencenbaugh L and Rew LJ (submitted 4/1/2025) Novel approaches to invasive grass management: assessing efficacy and impacts on plant diversity. Applied Vegetation Science.
- Integrated weed management