INTEGRATED MANAGEMENT OF RANGELAND INVASIVE PLANTS IN MONTANA

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1015647
• Project Start Date: Jul 1, 2018
• Project End Date: Jun 30, 2023
• Program Code: [(N/A)]- (N/A)

Recipient Organization
MONTANA STATE UNIVERSITY
(N/A)
BOZEMAN,MT 59717

Performing Department
Land Resources & Environmental Sciences

Non Technical Summary
Invasive weeds threaten rangeland health. Ecological impacts include altered structure, organization, and function of rangeland plant communities. Economically, weeds impact rangeland more than all other pests combined, including billions of dollars spent on control and reduction in livestock and wildlife carrying capacity. Containing existing populations and restoring rangeland severely degraded by weeds is critical for the ecology and economics of Montana agriculture. This purpose of this project is to improve the integrated management of rangeland weeds in Montana. More specifically, this project attempts to refine revegetation of weed-infested rangeland and investigates the ecology and integrated management of invasive annual grasses, in particular downy brome and ventenata.When weeds are controlled, niches are opened in the plant community. If desirable species are not present to re-occupy the site, then weeds are likely to re-establish. Revegetation attempts to alleviate this scenario by seeding desired species following weed control. Revegetation of weed-infested rangeland is expensive and often fails. Many factors contribute to the success or failure of revegetation, but one major challenge is overcoming the competitive advantage invasive plant seedlings have over seedlings of seeded species. In addition, the long-term success of revegetation in terms of suppressing re-invasion by invasive plants is not clear.Downy brome is considered one of the most noteworthy plant invasions in North America. Biological control,although often used with varying degrees of success on other weeds, is currently under development for downy brome. Pseudomonas fluorescens is a soil-borne bacterial pathogen that stunts root growth and overall vigor of downy brome by colonizing intercellular spaces in grass roots. Three strains of P. f/uorescens are being developed as bio-herbicides: D7, ACKSS, and MB906, and they are in various stages of commercial development. Jn spite of commercially available products whose primary ingredient is P. fluorescens, there are no peer-revie"':'ed, replicated field studies in the literature, and further research is warranted.Ventenata, like downy brome, is an exotic winter annual grass of increasing concern in Montana. It was first reported in North America in Idaho in the 1950s and has been reported to invade areas previously dominated by downy brome. Because of its newness as an invasive rangeland plant in the western U.S., there is limited information available on its biology, ecology, and management.The objectives of this project are to quantify the impact of planting time on the establishment of native grasses, test the efficacy of P. fluorescens strain ACKSS as a biological control (bio-herblcide) for downybrome, and expand our understanding of invasive annual grass ecology. A series of field and greenhouse studies will investigate these objectives. Research results may indicate that fall seeding or early spring seeding of native grasses are equally successful,revegetation may provide long-term suppression of leafy spurge, downy brome management may benefit from bio-herbicides, and the impacts of annual invasive grasses may vary depending on which invasive annual grass is dominant.

Animal Health Component

75%

Research Effort Categories

Basic

25%

Applied

75%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
213	0799	1070	100%

Knowledge Area
213 - Weeds Affecting Plants;

Subject Of Investigation
0799 - Rangelands and grasslands, general;

Field Of Science
1070 - Ecology;

Keywords

bromus tectorum

cheatgrass

downy brome

euphorbia esula

integrated pest management

invasive plant management

invasive plants

leafy spurge

rangeland

revegetation

ventenata dubia

weed management

weeds

Goals / Objectives
1. Improve methods for revegetating invasive plant-infested rangeland.Objective a) Quantify the impact of planting time on the establishment of native grasses and the invasive annual grass downy brome. Objective b) Evaluate long-term outcomes of integrating revegetation and herbicides to manage leafy spurge and other invasive plants.2. Increase our understanding of the ecology and integrated management of invasive annual grasses, in particular downy brome and ventenata.Objective a) Test the effect of the soil-borne pathogen Pseudomonas fluorescens on abundance of downy brome. Objective b) Test the effect of downy brome, Japanese brome (B. japonicus), ventenata, and medusahead on forage production, forage quality, litter decomposition, and grass seedling establishment. Objective c) Test effect of temperature and carbon dioxide concentrations on downy brome and ventenata.

Project Methods
1a) Quantify the impact of planting time on the establishment of native grasses and the invasive annual grass downy brome. This field study will evaluate the impact of planting time on the establishment of native perennial grasses in the presence of downy brome. The study will occur at a three rangeland or pasture sites with a nearmonoculture of downy brome and follow a split-plot, randomized complete block design with four replications. In each replication, 18 whole plots (12m x 3.5m) will be established and randomly assigned to a factorial combination of native grass (bluebunch wheatgrass) and planting time (approximately November 1, April 1, April 15, April 30, and May 15). Grasses will be drill seeded at a rate of 333 seeds/m2.Prior to the fall seeding treatment, plots will be split and half of each plot will be sprayed with glyphosate to control downy brome. Spring seeding treatments will be sprayed similarly in the spring prior toseeding. Native grass seedling emergence will be recorded weekly through mid-June and monthly thereafter until fall.Downy brome cover will be recorded in late June to early July. In June of the following two years, density, cover, and biomass of seeded native grass and down brome will be measured. Data will be analyzed using a mixed model analysis of variance. Pending funding and results of this study, further studies will investigate the influence of a late summer to early fall planting date in addition to a fall dormant and spring plantings.1b) Evaluate long-term outcomes of integrating revegetation and herbicides to manage leafy spurge and other invasive plants. In 2002 MSU and Missoula County Weed District began a research project near Lolo, MT, that integrated various methods to manage leafy spurge. Six grass seeding treatmentsand three herbicide treatmentswere factorially arranged and replicated four times at two sites. Whole plots (grass seeding treatment) were 13.7m x 4.3m, and split-plots (herbicide treatments) were 4.6m x 4.3m. Treatments were applied fall 2002, and plots were sampled for three years after treatment (2003-2005). Plots have been maintained, including fencing to exclude livestock and wildlife grazing, since their establishment. In June 2016 (14 years post-treatment) researchers, weed management professionals, and Extension field faculty gathered to sample the plots again. Density and biomass of leafy spurge and seeded grasses were sampled using methods similar to those from 2003 through 2005. Density was sampled in 0.1m2 frames, and biomass was clipped in 1m2 frames. Data will be analyzed using a bivariate mixed effects linear model, and long-term trends (2016 data) will be compared with short-term trends (2003-2005 data).2a) Test the effect of the soil-borne pathogen Pseudomonas fluorescens on abundance of downy brome. In early December 2014 P. fluorescens strain ACK55 was applied to 5m x 5m paired plots (treated, non-treated) and replicated eight times at eight locations (7 in Montana, 1 in Wyoming). Plots maintained by MSU are located at the Red Bluff Research Ranch near Norris, MT; other locations are near Miles City, MT (3), Missoula, MT (2), Florence, MT (1), and Bill, WY (1). Pseudomonas fluorescens strain ACK55 was applied in a freeze-dried form at a rate of 0.1 g per plot delivered in 702 mL deionized water. Plots have been sampled annually in early May 2015-2017, and sampling will continue through 2019. Percent cover of downy brome is sampled in one, 1m2 permanent frame placed in the center of each plot.Data will be analyzed using a mixed model analysis of variance.2b) Test the effect of downy brome, Japanese brome, ventenata, and medusahead on forage production, forage quality, litter decomposition, and grass seedling establishment.Thirteen rangeland sites across Montana that contain populations of downy brome, Japanese brome, medusahead, or ventenata were identified in summer 2017. At each site, weestablished 3, 100 meter transects spanning from zero to high degrees of annual grass infestation. Using a 0.5m2 frame, we sampled canopy cover by species, aiming for a total of seven frames per transect. We also estimated cover of bare ground and litter and measured litter depth within each frame. Biomass of the target invasive annual grass and perennial grasses was collected in two randomly chosen frames from the seven frames on each transect. Data will be analyzed using general linear regression.Forage quality of each invasive annual grass species and the native grasses bluebunch wheatgrass and western wheatgrass (Pascopyrum smithii), which were the two most commonly occurring species across field sites, will be assessed early in the growing season (April/May) and at peak biomass production (June/July). Biomass samples will be ground to 1mm using a Wiley mill and analyzed for crude proteinand total digestible nutrients. Data will be analyzed using mixed model analysis of variance.The rate of litter decomposition for the four invasive annual grasses and bluebunch wheatgrass and western wheatgrass will be investigated using mesh litter decomposition bags placed in the field for approximately 12 months and retrieved at regular intervals. Litter (biomass collected from 13 field sites) will be clipped into 5cm pieces, and 3g of litter of each species will be placed in 15cm x 15cm nylon mesh bags with 300nm openings. Bags will be secured to the surface of the soil at the MSU Arthur H. Post Research Farm and retrieved after one, three, six, nine, and 12 months. Four replications of each species will be retrieved at each sampling date. Upon retrieval, bags will be dried and weighed to the nearest 0.01g to determine litter mass loss due to decomposition. Data will be analyzed using mixed model analysis of variance.The effect of litter type and depth on seed germination and seedling growth for the four invasive annual grasses and bluebunch wheatgrass will be tested in a greenhouse study. Twentyseeds of each species will be sown into 10cm pots. Seeds will be sown either below or above a layer of plant litter. Each species will be planted in its own litter and the litter of every other species and replicated three times. In addition, five replications of 'control' pots will be seeded of each species with no litter. All pots will be watered regulary to prevent water stress. Seedlings will be allowed to grow for approximately 60 days, then above ground biomass will be clipped, dried, and weighed to the nearest 0.01 g. Percent emergence and days to 50% emergence willbe recorded. The study will be repeated once for a total of two trials. Data will be analyzed using mixed model analysis of variance.2c) Test effect of temperature and carbon dioxide concentrations on downy brome and ventenata. This growth chamber study will cross three temperature treatments by three carbon dioxide treatments across two invasive annual grass species. Temperature treatments will mimic current and mid- and late-Century projections for the Southwestern Montana Climate Division based on climate models developed by the Montana Climate Office. Carbon dioxide treatments will mimic current and mid- and late Century projections for the United States. Downy brome and ventenata will be seeded individually into 4cm pots.Seedlings will be culled to achieve one plant per pot.Plants will be allowed to grow for 30 to 45 days after which the number of tillers and tiller height will be recorded. Above and below ground biomass will be harvested, dried, and weighed to the nearest 0.01g.Soil moisture will be monitored throughout the study and photosynthetic rate will be monitored periodically to determine the effect of varying carbon dioxide and temperature treatments on plant physiology. All treatments will be replicated five times. The study will be repeated once for a total of two trials, pending availability of growth chamber space. Data will be analyzed using mixed model analysis of variance.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Agricultural producers (e.g. livestock producers or ranchers), managers of state and fedreally-administered public lands, county noxious weed district coordinators, Extension agents, small acreage owners, and other researchers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One graduate student working on her Master of Science degree completed her programs working on research associated with this project. One undergraduate student worked on research related to this project over the last year. How have the results been disseminated to communities of interest?Twenty-three presentations were given to the project's target audience, reaching about 1,100 people. These presentations included research results from some of the objectives of this proposal, as well as general information on management of invasive plants on rangelands in Montana. Two MSU Extension Monthly Weed Posts included information obtained from research conducted as part of this project [see June 2020 (http://msuinvasiveplants.org/extension/monthly-weed-posts/202006mwp-june-field-trials-cheatgrass-suppressive-bacteria.html) and March 2020 (https://www.youtube.com/watch?v=if2wKRfdWYY)]. The Monthly Weed Post reaches about 500 people across the U.S., mostly in the western region of the country. What do you plan to do during the next reporting period to accomplish the goals?Work will continue on analyzing data and writing manuscripts for studies related to this project. Dissemination of results to targeted audience will continue as well.

Impacts
What was accomplished under these goals? Progress was made on Objective 1a) Quantify the impact of planting time on the establishment of native grasses and the invasive annual grass downy brome. We completed field studies at one rangeland and two pasture sites infested with downy brome. One site was near Belgrade, MT, and the other two sites were near Corvallis, MT. Fall and spring seeding treatments were applied along with glyphosate treatments in 2017 and 2018. Bluebunch wheatgrass frequency, cover, density, and biomass and downy brome cover and biomass were collected in late June (sites near Corvallis) and early July (site near Belgrade) 2018 and 2019. Results of the study were included in Master of Science thesis for graduate student Michelle Majeski, and the thesis chapter is being prepared as a manuscript to submit later 2020 or early 2021. In summary, bluebunch wheatgrass density was higher with spring seeding dates compared to the fall seeding date. In the second year after spring seeding, bluebunch density ranged from 6 to 25 plants per m2 and was facilitated by herbicide application. Specifically, spring herbicide application was more effective than fall application. Between the two seasonal applications, spring herbicide reduced downy brome cover three-fold at one site. Our results show that a spring herbicide application to control downy brome followed by spring seeding of bluebunch wheatgrass established a seasonal priority effect for bluebunch wheatgrass, resulting in its increased density and cover. Restoration practitioners have a more strategic and ecologically-based option with timing of herbicide application and seeding bluebunch wheatgrass based on the results of this study, which is promising for downy brome-infested range and pasture lands. Another study that was a precursor to this study was finalized in 2019. Graduate student Audrey Harvey completed her Master of Science degree, and the manuscript we submitted has now been published in Ecological Restoration. This study showed that native grass seeding is best employed late fall through early spring (April), resulting in larger plants than seeding later in spring (May). Furthermore, fall to early spring seeding increased a grass stand's resistance to invasion by downy brome. Progress was made on Objective 1b) Evaluate long-term outcomes of integrating revegetation and herbicides to manage leafy spurge and other invasive plants. We quantified the long-term outcomes of seeding perennial grasses into rangeland infested with leafy spurge. A manuscript submitted in 2019 was published in Rangeland Ecology and Management, and the project was presented at the joint conference of the Weed Science Society of America/Western Society of Weed Science in March 2020. Fourteen years after seeding, the most productive grass, bluebunch wheatgrass (Pseudoroegneria spicata) produced about 900 kg ha-1, which was about 70% of total plant community biomass. Leafy spurge became less productive in all plots, and seeded and non-seeded plots produced similar leafy spurge biomass 14 years after seeding. Although seeding did not have a direct effect on leafy spurge biomass, bluebunch wheatgrass reduced exotic grasses by about 85%. Our study, combined with past studies, identified invaded habitats where seeded grasses have a good possibility of persisting as productive stands. For Objective 2a) Test the effect of the soil-borne pathogen Pseudomonas fluorescens on abundance of downy brome, a multi-author manuscript was accepted in Rangeland Ecology and Management and it has been published on line and is awaiting publication. Four other manuscripts were accepted and are being published alongside our publication in a special section of the journal. Our results from sites across Montana (6 sites) and Wyoming (1 site) showed that P. fluorescens is not a reliable tool for controlling downy brome in the Northern Great Plains and Central Rocky Mountains. After sampling pair-plots across all sites for four years post-application, there was no difference between treated and non-treated plots. Progress on Objective 2b) Test the effect of downy brome, Japanese brome (B. japonicus), ventenata, and medusahead on forage production, forage quality, litter decomposition, and grass seedling establishment was minimal. Other than the results of this project being presented in Extension seminars throughout Montana, a manuscript is in-progress with plans to submit in 2021. Finally, progress was made on Objective 2c) Test effect of temperature and carbon dioxide concentrations on downy brome and ventenata. The greenhouse study was conducted, data were analyzed, and summarized in a manuscript that is in review with the journal Agronomy. In summary, we found that downy brome grew larger than ventenata across ambient and elevated temperature and carbon dioxide concentrations. However, ventenata allocated more growth to its roots than downy brome, a difference that remained consistent across climate conditions. This suggests ventenata may have a competitive advantage over downy brome for accessing soil resources (e.g. nutrients and water) under elevated temperature and carbon dioxide conditions.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Harvey, AJ**, SC Simanonok***, LJ Rew, TS Prather, and JM Mangold (2020) Effect of Pseudoroegneria spicata (bluebunch wheatgrass) seeding date on establishment and resistance to invasion by Bromus tectorum (cheatgrass). Ecological Restoration 38:145-152.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Rinella, M, AD Knudsen, JS Jacobs, and JM Mangold (2020) Seeding causes long-term increases in grass forage production in invaded rangelands. Rangeland Ecology and Management 73:329-333.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Gaskin, JF, E Espeland, CD Johnson, DL Larson, JM Mangold, RA McGee, C Milner, S Paudel, DE Pearson, LB Perkins, CW Prosser, JB Runyon, SE Sing, ZA Sylvain, AJ Symstad, DR Tekiela (2020) Managing invasive plants on Great Plains grasslands: A discussion of current challenges. Rangeland Ecology and Management.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Reinhart, K, C Carlson, K Feris, M Germino, C Jandreau, B Lazarus, J Mangold, D Pellatz, P Ramsey, M Rinella, and M Valliant (2020) Weed-suppressive bacteria fails to control Bromus tectorum under field conditions. Rangeland Ecology and Management
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Rinella MJ, AD Knudsen, JS Jacobs, and JM Mangold (2020) Seeding causes long-term increases in grass forage production in invaded rangelands. Joint Meeting of the Weed Science Society of America and the Western Society of Weed Science. Maui, HI. 2-5 March
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Majeski, M, C Zabinski, L Rew, and J Mangold (2020) Do certain nutrients and plant-soil feedbacks affect Ventenata dubia (Ventenata)? Joint Meeting of the Weed Science Society of America and the Western Society of Weed Science. Maui, HI. 2-5 March
• Type: Theses/Dissertations Status: Published Year Published: 2020 Citation: Majeski, M (2020) Understanding mechanisms of invasion and restoring lands impacted by non-native annual grasses. Master of Science thesis, Montana State University. 157 pp.
• Type: Journal Articles Status: Under Review Year Published: 2020 Citation: Harvey,AJ, LJ Rew, TS Prather, and JM Mangold (in review) Effects of elevated temperature and CO2 concentration on seedling growth of Ventenata dubia and Bromus tectorum. Agronomy.

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:Agricultural producers (e.g. livestock producers), managers of state and federally-administered lands, county weed district coordinators, Extension agents, small acreage owners, and other researchers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One graduate student received her Master of Science degree while working on objectives associated with this project. Another Master of Science graduate student is progressing toward receiving her degree, working on objectives associated with this project. How have the results been disseminated to communities of interest?About 30 presentations were given to the project's target audience. These presenetations included research results from some of the objectives of this proposal, as well as general information on management of invasive plants on rangelands in Montana. What do you plan to do during the next reporting period to accomplish the goals?Complete analysis of data for Objective 1a and summarize in thesis chapter; submit manuscript for peer-review. For Objective 1b, present results at Weed Science Society of America/Western Society of Weed Science annual meeting as well as at Extension presentations in Montana. Submit manuscript for peer-review for Objective 2a, focusing on annual grass impacts to forage production and quality.

Impacts
What was accomplished under these goals? Progress was made on Objective 1a) Quantify the impact of planting time on the establishment of native grasses and the invasive annual grass downy brome. Field studies were established at one rangeland and two pasture sites infested with downy brome. One site is near Belgrade, MT, and the other two sites are near Corvallis, MT. Fall and spring seeding treatments were applied along with glyphosate treatments in 2017 and 2018. Bluebunch wheatgrass frequency, cover, density, and biomass and downy brome cover and biomass were collected in late June (sites near Corvallis) and early July (site near Belgrade) 2019. Data are being explored and analyzed. Graduate student working on this project is analyzing data and beginning to write a manuscript. Another study that was a precursor to this study was finalized in 2019. A graduate student completed her Master of Science degree, and we submitted a manuscript for peer-review. This study showed that native grass seeding is best employed late fall through early spring (April), resulting in larger plants than seeding later in spring (May). Furthermore, fall to early spring seeding increased a grass stand's resistance to invasion by downy brome. Progress was made on Objective 1b) Evaluate long-term outcomes of integrating revegetation and herbicides to manage leafy spurge and other invasive plants. We quantified the long-term outcomes of seeding perennial grasses into rangeland infested with leafy spurge. In 2019 a manuscript was submitted and accepted for publication in Rangeland Ecology and Management. Fourteen years after seeding, the most productive grass, bluebunch wheatgrass (Pseudoroegneria spicata) produced about 900 kg ha-1, which was about 70% of total plant community biomass. Leafy spurge became less productive in all plots, and seeded and non-seeded plots produced similar leafy spurge biomass 14 years after seeding. Although seeding did not have a direct effect on leafy spurge biomass, bluebunch wheatgrass reduced exotic grasses by about 85%. Our study, combined with past studies, identified invaded habitats where seeded grasses have a good possibility of persisting as productive stands. For Objective 2a) Test the effect of the soil-borne pathogen Pseudomonas fluorescens on abundance of downy brome, downy brome cover in the paired-plots (treated and non-treated) were sampled and data were shared with the project coordinator Dr. Kert Reinhart. Dr. Reinhart was first author on a multi-author manuscript that has been accepted in Rangeland Ecology and Management. Our results from sites across Montana (6 sites) and Wyoming (1 site) showed that P. fluorescens is not a reliable tool for controlling downy brome in the Northern Great Plains and Central Rocky Mountains. After sampling pair-plots across all sites for four years post-application, there was no difference between treated and non-treated plots. Progress was also made on Objective 2b) Test the effect of downy brome, Japanese brome (B. japonicus), ventenata, and medusahead on forage production, forage quality, litter decomposition, and grass seedling establishment. Results from the study that looked at the effect of downy brome, Japanese brome, ventenata, and medusahead on forage production and quality were shared at an academic conference (Western Society of Weed Science) and multiple Extension-type presentations throughout Montana and the region, including Alberta, Canada. A manuscript is in-progress with plans to submit in 2020. We are analyzing data for the studies examining the effect of these four annual grasses on litter decomposition and grass seedling establishment. Finally, progress was made on Objective 2c) Test effect of temperature and carbon dioxide concentrations on downy brome and ventenata. The greenhouse study was conducted, data were analyzed, and summarized in a manuscript that has been submitted for peer-review. In summary, we found that downy brome grew larger than ventenata across ambient and elevated temperature and carbon dioxide concentrations. However, ventenata allocated more growth to its roots than downy brome, a difference that remained consistent across climate conditions. This suggests ventenata may have a competitive advantage over downy brome for accessing soil resources (e.g. nutrients and water) under elevated temperature and carbon dioxide conditions.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Harvey A, J Mangold, LJ Rew, T Prather (2019) The effects of elevated temperature and CO2 on Ventenata dubia and Bromus tectorum seedling growth. 72nd meeting of the Western Society of Weed Science. Denver, CO.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Mangold J, S. Davis, L Rew (2019) Is one invasive annual grass worse than another? 72nd meeting of the Western Society of Weed Science. Denver, CO.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Majeski M, S Davis, Z Miller, J Mangold (2019) Modifying seeding date of Pseudoroegneria spicata (bluebunch wheatgrass) during revegetation to limit re-invasion by Bromus tectorum (downy brome). 72nd meeting of the Western Society of Weed Science. Denver, CO.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2019 Citation: Reinhart K, C Carlson, K Feris, M Germino, C Jandreau, B Lazarus, J Mangold, D Pellatz, P Ramsey, M Rinella, M Valliant (In press) Weed-suppressive bacteria fails to control Bromus tectorum under field conditions. Rangeland Ecology and Management.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Ehlert KA, Z Miller, J Mangold, F Menalled, A Thornton (2019) Temperature effects on three Bromus tectorum (cheatgrass, downy brome) seed collections inoculated with the fungal pathogen Pyrenophora semeniperda. Invasive Plant Science and Management 12:150-154.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Ehlert KA, JM Mangold, F Menalled, Z Miller, A Dyer (2019) Seeding, herbicide, and fungicide impact on perennial grass establishment in cheatgrass infested habitats. Ecological Restoration 37:67-70.
• Type: Journal Articles Status: Under Review Year Published: 2020 Citation: Harvey AJ, SC Davis, LJ Rew, TS Prather, JM Mangold (In review) Effect of Pseudoroegneria spicata (bluebunch wheatgrass) seeding date on establishment and subsequent ability to resist invasion by Bromus tectorum (cheatgrass). Ecological Restoration.
• Type: Journal Articles Status: Submitted Year Published: 2020 Citation: Harvey, AJ, L Rew, T Prather, J Mangold (submitted) Effects of elevated temperature and CO2 concentration on seedling growth of Ventenata dubia and Bromus tectorum. Western North American Naturalist.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Rinella MJ, AD Knudsen, JS Jacobs, JM Mangold (In press) Seeding causes long-term increases in grass forage production in invaded rangelands. Rangeland Ecology and Management.
• Type: Theses/Dissertations Status: Published Year Published: 2019 Citation: Harvey AJ (2019) Understanding the biology, ecology, and integrated management of Ventenata dubia. Master of Science thesis. Montana State University. 129 pp.

Progress 07/01/18 to 09/30/18

Outputs
Target Audience:Target audiences include agricultural producers (e.g. livestock producers), managers of state and federally-administered lands, county weed district coordinators and Extension agents, small acreage owners, and other researchers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two graduate students pursuing M.S. degrees are working on projects related to those presented here. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?Complete data analysis for Objectives 2b and 2c. Continue field sampling for Objective 1a. Prepare manuscript relateed to Objective 2b.

Impacts
What was accomplished under these goals? Progress was made on Objective 1a) Quantify the impact of planting time on the establishment of native grasses and the invasive annual grass downy brome. Field studies were established at one rangeland and two pasture sites infested with downy brome. One site is near Belgrade, MT, and the other two sites are near Corvallis, MT. Fall and spring seeding treatments were applied along with glyphosate treatments. Bluebunch wheatgrass frequency, cover, and density and downy brome cover were collected in late June (sites near Corvallis) and early July (site near Belgrade). Data are being explored and analyzed. For Objective 2a) Test the effect of the soil-borne pathogen Pseudomonas fluorescens on abundance of downy brome, downy brome cover in the paired-plots (treated and non-treated) were sampled and data were shared with the project coordinator Dr. Kert Reinhart. Progress was also made on Objective 2b) Test the effect of downy brome, Japanese brome (B. japonicus), ventenata, and medusahead on forage production, forage quality, litter decomposition, and grass seedling establishment. Statistical models were built for estimating the impact of the four invasive annual grasses on forage production; these models continue to be refined but in general we found the relationship between annual and perennial grass cover does change based on the target annual grass in consideration. There was a negative relationship at downy brome and ventenata sites, and no relationship at Japanese brome or medusahead sites (see figure below). In particular, for every 1% increase in annual grass cover, there was a 0.39% ± 0.05% decrease in perennial grass cover at downy brome sites. Downy brome sites had an average of 24.8% cover of downy brome and 18.5% perennial grass cover. At ventenata sites, for every 1% increase in annual grass cover, there was a 0.48% ± 0.08% decrease in perennial grass cover. Ventenata sites had an average of 25.0% cover of ventenata and 20.2% perennial grass cover. We found no association between annual grass cover and perennial grass cover at Japanese brome sites. Japanese brome cover averaged 13.7% while perennial grass cover averaged 25.2%. We found no association between annual grass cover and perennial grass cover at the medusahead site. Medusahead cover averaged 17.3% at the one site while perennial grass cover averaged 3.8%. Under this objective we also completed forage analyses for each of the invasive annual grasses and two native grasses. Early season samples were collected from mid-May to early June 2018 while mid-season samples were collected during peak biomass production from early June to early August 2017. We selected western wheatgrass and bluebunch wheatgrass as our native perennial grasses of interest due to their high presence and abundance across our field sampling sites in summer 2017. We composited biomass of individual species collected as part of our field sampling in 2017 across each site into one sample per species for the mid-season samples. For the early season samples, we collected biomass of the six species from three distinct sites in 2018 to have three replicates per species (only one site for medusahead due to limited presence in Montana). All species during the early sampling period were either in leaf or early heading growth stages. Biomass samples were ground using a Wiley mill at Montana State University and were analyzed for crude protein content (assessed from nitrogen content) and total digestible nutrients (using neutral and acid detergent fiber tests). A subset of samples was analyzed for acid insoluble ash (i.e., silica) at Cumberland Valley Analytical Services. We found no differences in crude protein (CP) among the five grass species we tested for early season forage quality (p=0.132, F=2.285, df=4,10). Crude protein for the two native perennial grasses averaged 16%. Values for the invasive annual grasses were as follows: downy brome and Japanese brome averaged 14%, and ventenata averaged 10%. Medusahead CP at the one site we examined was 10% (not compared statistically). Crude protein for mid-season forage quality was not statistically analyzed but CP values were lower than early season values. We found some differences in neutral detergent fiber (NDF) among the five grass species we tested for early season forage quality (p=0.005, F=7.525, df=4,10). Specifically, downy brome had lower NDF than ventenata, bluebunch wheatgrass, and western wheatgrass. Additionally, Japanese brome had lower NDF than bluebunch wheatgrass. There were no other differences in NDF. Mid-season NDF was not statistically analyzed but values were higher than early season values (see table below). Acid neutral fiber (ADF) values represent the level of cellulose and lignin in the grasses. Lignin is considered indigestible by the animal so the lower ADF, the more digestible the grass. We found no differences in acid neutral fiber (ADF) between the five grass species we tested for early season forage quality. ADF for mid-season forage quality was not statistically analyzed, but values were higher than early season values. Silica values for invasive annual grasses ranged from 2.9-9.2% while silica values for native perennial grasses ranged from 3.4-3.8%. Downy brome had the lowest silica value of 2.9% compared to ventenata, which had the highest value at an average of 8.9%. Medusahead had the second highest silica value of 7.7%. Finally, some progress was made on Objective 2c) Test effect of temperature and carbon dioxide concentrations on downy brome and ventenata. The greenhouse study was conducted, and data are being analyzed.

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