Research in our lab focuses on integrating tools (e.g., prevention; chemical, mechanical, and biological control; prescribed fire; revegetation) to manage invasive plants on rangeland in Montana.  We aim to find ecologically-based, economically viable means to control invasive plants while maintaining or restoring desirable vegetation that meets management objectives.

Research: in progress

people sampling annual grass cover on a hillside along a transect

A comprehensive look at invasive annual grasses

Collaborators: Lisa Rew (MSU) and Kate Fuller (MSU)

We are examining how four invasive annual grasses (cheatgrass, Japense brome, Ventenata, and medusahead) are impacting our economy, forage quality, and rangeland biodiversity. We sampled at a total of 13 sites across Montana in 2017 and will be researching litter decomposition and litter effects on germination from 2017 to 2018.

cheatgrass field near Belgrade in the fall showing fall herbicide application dye

Optimal seeding date and preparation for planting perennial grass into weedy areas

Collaborator: Zach Miller (MSU)

Planting date of desired grasses can influence competition with weeds and ultimate success of restoration/revegetation planting. This project will identify optimal timing of grass seeding when revegetating weed-infested range and pasture lands. The project will also evaluate if timing of weed management influences optimal seeding time/conditions.

cattle grazing on rangeland in Montana with calf in foreground

Noxious weeds and Montana grazing lands: An economic perspective

Collaborators: Kate Fuller (MSU) and Matt Rinella (USDA-ARS)

We developed a 16-question survey concerning noxious weed management and associated costs. The target audience for the survey was livestock producers who were grazing their livestock on privately-owned rangeland in Montana. See our article in a recent issue of the Montana IPM bulletin for results.

close up of Canada thistle flowers on the left and close up of field bindweed flower on the right

A meta-analysis of previous Canada thistle (Cirsium arvense) and field bindweed (Convolvulus arvensis) control and mangement studies

Collaborators: Fabian Menalled (MSU) and Zach Miller (MSU)

We are using meta-analysis, to 1) provide land managers with effective control measures for Canada thistle and field bindweed based on current knowledge, 2) systematically compile methods to manage impacted sites, and 3) identify existing knowledge gaps in the management of these two species.

field technician collecting hoary alyssum plants kneeling on ground holding a plant

The effect of herbicide application and soil texture on hoary alyssum (Berteroa incana) seed biology and control

Southwestern MT

Hoary alyssum can be difficult to manage, possibly due to its prolonged flowering period when populations are simultaneously flowering and producing seeds, in addition to the fact that it often grows on coarsely textured soils where control with herbicides may be reduced. Our objectives of this project are to 1) quantify hoary alyssum seed production and viability as influenced by herbicide application and 2) determine the influence of soil texture on efficacy of herbicides applied to hoary alyssum. This project started  summer 2016.

person standing in plot area with bluebunch wheatgrass growing in a fallow crop field

Mitigating priority effects of invasive plants during revegetation by altering perennial grass planting date

Bozeman, MT

Modifying seeding date may be one ecologically-based management tool to increase establishment of seeded species by giving them an initial size advantage over weedy species that emerge later. This project is exploring how timing of planting of desirable perennial grasses (bluebunch wheatgrass) might overcome the priority effects of seedlings of the invasive plants spotted knapweed and cheatgrass. It is our hope that this research will improve efficacy of revegetation efforts on lands dominated by spotted knapweed and cheatgrass in Montana and other semi-arid regions. This project started fall 2015.

medusahead seed head in the palm of someone's hand

Monitoring a new invader: medusahead (Taeniatherum caput-medusae) in Sanders County

Sanders County

The presence of medusahead, an invasive annual grass, was confirmed in Montana for the first time in 2013. In 2014, 2015, and 2016, MSU researchers from the Mangold lab surveyed frequency of medusahead, along with other plant functional groups, at the confirmed site. This monitoring project will allow us to track the rate and spread of medusahead. Click here to download a MSU Extension bulletin on medusahead.


Integrating Pyrenophora semeniperda into cheatgrass management in range and croplands

Krista Ehlert, Former PhD Student

I am investigating the effect of P. semeniperda on target (Bromus tectorum) and non-target species in a greenhouse study. Future studies will evaluate if a fungicide seed treatment can prevent or reduce P. semeniperda infection and mortality of non-target species. I am also determining which combination of three cheatgrass plant stages (early flowering, peak flowering, and after seed maturation) and three inoculation timings (morning, evening, none) enhance P. semeniperda infection. I am finally seeing if cultural, chemical, and biological practices can be integrated to improve cheatgrass management in crop and rangeland settings.

technician sampling percent cover on a hillside rangeland with mountains in the background

Rangeland resilience - when is revegetation necessary?

Central and western MT

The objective of this project is to determine how an herbicide application for target weeds affects abundance of rangeland plant functional groups one and two years post-spraying. Aminopyralid (MilestoneĀ®) was applied at two spotted knapweed infested rangeland sites and two sulfur cinquefoil infested rangeland sites, while picloram (TordonĀ®) was applied at two Dalmatian toadflax infested rangeland sites. We have collected data in 2014 and 2015, one and two years post-treatment.

Research: completed

crop field with rows of crop growing with yellow flowered weed growing in between

Management strategies for control of narrowleaf hawksbeard (Crepis tectorum)

Collaborators: Shelley Mills and Bobbie Roos (MSU Extension Agents)

Narrowleaf hawksbeard is not a state listed noxious weed, but it is becoming increasingly problematic in Montana cropland and CRP lands, especially in the northeastern part of the state. This study looked at herbicide and mowing management options at two sites in Daniels County and Valley County. Herbicides applied in the fall were less effective on narrowleaf hawskbeard but were less detrimental to desirable forbs. Optimal control of narrowleaf hawksbeard with herbicides used in the study may be achieved by application in the spring. Mowing alone is not recommended as a viable management option but may enchance control in combination with spring herbicides.

people sampling a revegetation site with mountains in background

Rangeland revegetation revisited: are short-term trends indicative of long-term outcomes?


PDF (Copyright by the Ecological Society of America)

people applying treatments to field plots in crop field

Joint effects of biotic and abiotic stressors on winter wheat suppression of Bromus tectorum

Noelle Orloff, Former MS Graduate Student
person sitting in plot with seeded grass growing and cheatgrass growing around the plot

Site-specific effects of exotic annual grass control integrated with revegetation

Noelle Orloff, Former MS Graduate Student
pots in greenhouse with cheatgrass and a native perennial grass growing

Role of size and nitrogen in competition between annual and perennial grasses

Noelle Orloff, Former MS Graduate Student
bee species foraging on a spotted knapweed flower

Temporal- and density-dependent impacts of an invasive plant on pollinators and pollination services to a native plant

Christina Herron-Sweet, Former MS Graduate Student
several spotted knapweed flowers and buds with trees in the background

Native parasitoids associated with the biological control agents of Centaurea stoebe in Montana

Christina Herron-Sweet, Former MS Graduate Student
research plots mowed and not mowed with tall buttercup growing

Testing integrated management strategies for tall buttercup (Ranunculus acris) in irrigated hayfield meadows

Hally Strevey, Former MS Graduate Student
bromus tectorum seeds with fungal pathogen growing on top of blue blotter paper

Integrating the herbicide imazapic and the fungal pathogen Pyrenophora semeniperda to control Bromus tectorum

Krista Ehlert, Former MS Graduate Student
cheatgrass site

Imazapic activity in a semiarid climate in downy brome (Bromus tectorum)-infested rangeland and CRP sites

Krista Ehlert, Former MS Graduate Student
person sitting in field of western salsify that is dispersing seeds

Testing control options for western salsify (Tragopogon dubius) on Conservation Reserve Program Lands