Cheatgrass and Medusahead Active
Invasive annual grasses, such as cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae), are one of the most significant stressors to rangeland ecosystems in the western U.S. Their expansion and dominance across this area are the most damaging ecosystem agents on this iconic landscape.
Many invasive plants thrive in disturbed areas and are easily spread through various pathways and vectors. In the western U.S., disturbed landscape can take the form of areas changed by human development, improper grazing, and burned by wildfire. Roads and trails, and the vehicles that travel them, transmission corridors, and fuel breaks all serve as pathways and vectors that help spread these unwanted invaders. Once an invasive plant becomes established in an area, it can quickly spread across the landscape. Invasive plant species can become ecologically dominant, creating near-monocultures that result in reduced wildlife habitat, recreational opportunities, livestock forage, and altered fire regimes. Even after landscape disturbances are removed from areas dominated by these plants, these invasive annual grasses can remain the dominant plant.
Cheatgrass originated in Europe or Eurasia and medusahead in the Mediterranean region. Both were introduced to the U.S. in the mid- to late-1800's as a contaminant in seed and straw. Both species germinate in the fall and early spring, grow rapidly and in high numbers making them highly competitive with native species.
Plants native to the sagebrush landscape may not recover from disturbances that allow invasive annual grasses to over-run them, even decades later. In these areas, elimination of invasive annual grasses is very difficult because the limited number of remaining native plants are unable to produce seeds and seedlings that can compete with these invasive annual grasses. In addition, the thick thatch produced by annual grasses kills biological soil crusts (lichens, mosses and cyanobacteria) that once filled the soil interspaces between the native grasses and shrubs.
The conversion of a diverse native ecosystem to simple invasive grass-dominated ecosystems degrades the ecosystem processes leading to soil erosion, less water in the soil for plant growth, and changes in nutrient cycling, making a less productive land that is much harder to restore to what it was before the invasion.
Land managers are tasked with controlling cheatgrass and medusahead, but resources are limited for invasive plant management. They face difficult decisions on how to use their limited resources. Do they target high-risk pathways and vectors of invasion for efficiency, focus on specific invasive plant patches that are feasible to control, or treat the periphery of a large invasion to slow and contain the spread? Innovative approaches that capitalize on the targeted ecosystem’s resilience to disturbance and resistance to invasive plant invasion is needed to achieve long-term ecosystem conservation and restoration goals for invasive plant-dominated landscapes.
Researchers at the USGS have and continue to develop a wide variety of tools and systems, and answer questions, that help tribal, federal, state, industry, and private land managers design and implement sustainable rangeland practices along with effective restoration and rehabilitation projects. Studies focus on finding ways to control cheatgrass and medusahead through use of herbicides, soil bacteria, and targeted grazing. On-going research also answers questions about the resistance of an ecosystem to an invasive plant, including the suitability of the ecosystem’s climate and soils for establishment and persistence of the invasive plant, and the capacity of the native plant community to prevent increases in the invasive plant’s population through factors such as competition, herbivory, and ability of native plants, including biological soil crusts, to adapt to environmental conditions. They develop solutions to help land managers bolster or support the ecosystem's resilience, or ability to bounce back from a disturbance.
Notable contributions include:
Exotic Brome-Grasses in the Western U.S. Edited and contributed to the authoritative source of information on exotic annual Bromus in arid and semi-arid ecosystems of the western U.S.
Indicators of Rangeland Health. Development of the best, most consistent, and comparable method to determine rangeland health. This method is widely used by multiple land management agencies and highly
valued by ranchers.
Right Seed at the Right Place and Time. Tests of seed sources used in BLM restoration efforts changed seed transfer guidelines and enhanced seeding success. Our data helps the BLM, the largest purchaser of
wildland seed globally, buy the right kind and amount of seed.
Conservation Efforts Database. Constructed a data system that helped the USFWS determine if stakeholder conservation efforts were enough to avoid an Endangered Species Act listing of the Greater sage-grouse.
Restoration of biological soil crusts. Tests of species for restoration, impacts of grazing and fire are of interest to BLM, USFWS, and USFS managers to enhance restoration successes.
Browse the Publications and Data and Tools tabs to find USGS publications related to invasive annual grasses.
Check out the News tab for plain language descriptions of USGS studies and publications.
Click the Multimedia tab for pictures and maps.
Visit the team pages for the scientists working on invasive annual grasses.
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
Below are downloadable images related to cheatgrass and medusahead.
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
Fungal and bacterial contributions to nitrogen cycling in cheatgrass-invaded and uninvaded native sagebrush soils of the western USA
Seventy-five years of vegetation treatments on public rangelands in the Great Basin of North America
Filling the interspace—restoring arid land mosses: source populations, organic matter, and overwintering govern success
Soil moisture and biogeochemical factors influence the distribution of annual Bromus species
Plant community resistance to invasion by Bromus species: The roles of community attributes, Bromus interactions with plant communities, and Bromus traits
Ecosystem impacts of exotic annual invaders in the genus Bromus
Land uses, fire, and invasion: Exotic annual Bromus and human dimensions
Introduction: Exotic annual Bromus in the western USA
Long-term effects of seeding after wildfire on vegetation in Great Basin shrubland ecosystems
Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America
Nitrogen limitation, 15N tracer retention, and growth response in intact and Bromus tectorum-invaded Artemisia tridentata ssp. wyomingensis communities
Effects of resource availability and propagule supply on native species recruitment in sagebrush ecosystems invaded by Bromus tectorum
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
Land Treatment Exploration Tool
The Land Treatment Exploration Tool is designed for resource managers to use when planning land treatments. The tool provides useful summaries of environmental characteristics of planned treatment areas and facilitates adaptive management practices by comparing those characteristics to other similar treatments within a specified distance or area of interest. Provisional Software.
Plain language descriptions for some related USGS products and publications.
New Invasive Annual Grass Book Addresses Critical Questions for the Western U.S.
- Overview
Invasive annual grasses, such as cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae), are one of the most significant stressors to rangeland ecosystems in the western U.S. Their expansion and dominance across this area are the most damaging ecosystem agents on this iconic landscape.
Many invasive plants thrive in disturbed areas and are easily spread through various pathways and vectors. In the western U.S., disturbed landscape can take the form of areas changed by human development, improper grazing, and burned by wildfire. Roads and trails, and the vehicles that travel them, transmission corridors, and fuel breaks all serve as pathways and vectors that help spread these unwanted invaders. Once an invasive plant becomes established in an area, it can quickly spread across the landscape. Invasive plant species can become ecologically dominant, creating near-monocultures that result in reduced wildlife habitat, recreational opportunities, livestock forage, and altered fire regimes. Even after landscape disturbances are removed from areas dominated by these plants, these invasive annual grasses can remain the dominant plant.
Cheatgrass originated in Europe or Eurasia and medusahead in the Mediterranean region. Both were introduced to the U.S. in the mid- to late-1800's as a contaminant in seed and straw. Both species germinate in the fall and early spring, grow rapidly and in high numbers making them highly competitive with native species.
Plants native to the sagebrush landscape may not recover from disturbances that allow invasive annual grasses to over-run them, even decades later. In these areas, elimination of invasive annual grasses is very difficult because the limited number of remaining native plants are unable to produce seeds and seedlings that can compete with these invasive annual grasses. In addition, the thick thatch produced by annual grasses kills biological soil crusts (lichens, mosses and cyanobacteria) that once filled the soil interspaces between the native grasses and shrubs.
The conversion of a diverse native ecosystem to simple invasive grass-dominated ecosystems degrades the ecosystem processes leading to soil erosion, less water in the soil for plant growth, and changes in nutrient cycling, making a less productive land that is much harder to restore to what it was before the invasion.
Land managers are tasked with controlling cheatgrass and medusahead, but resources are limited for invasive plant management. They face difficult decisions on how to use their limited resources. Do they target high-risk pathways and vectors of invasion for efficiency, focus on specific invasive plant patches that are feasible to control, or treat the periphery of a large invasion to slow and contain the spread? Innovative approaches that capitalize on the targeted ecosystem’s resilience to disturbance and resistance to invasive plant invasion is needed to achieve long-term ecosystem conservation and restoration goals for invasive plant-dominated landscapes.
Researchers at the USGS have and continue to develop a wide variety of tools and systems, and answer questions, that help tribal, federal, state, industry, and private land managers design and implement sustainable rangeland practices along with effective restoration and rehabilitation projects. Studies focus on finding ways to control cheatgrass and medusahead through use of herbicides, soil bacteria, and targeted grazing. On-going research also answers questions about the resistance of an ecosystem to an invasive plant, including the suitability of the ecosystem’s climate and soils for establishment and persistence of the invasive plant, and the capacity of the native plant community to prevent increases in the invasive plant’s population through factors such as competition, herbivory, and ability of native plants, including biological soil crusts, to adapt to environmental conditions. They develop solutions to help land managers bolster or support the ecosystem's resilience, or ability to bounce back from a disturbance.
Notable contributions include:
Exotic Brome-Grasses in the Western U.S. Edited and contributed to the authoritative source of information on exotic annual Bromus in arid and semi-arid ecosystems of the western U.S.
Indicators of Rangeland Health. Development of the best, most consistent, and comparable method to determine rangeland health. This method is widely used by multiple land management agencies and highly
valued by ranchers.Right Seed at the Right Place and Time. Tests of seed sources used in BLM restoration efforts changed seed transfer guidelines and enhanced seeding success. Our data helps the BLM, the largest purchaser of
wildland seed globally, buy the right kind and amount of seed.Conservation Efforts Database. Constructed a data system that helped the USFWS determine if stakeholder conservation efforts were enough to avoid an Endangered Species Act listing of the Greater sage-grouse.
Restoration of biological soil crusts. Tests of species for restoration, impacts of grazing and fire are of interest to BLM, USFWS, and USFS managers to enhance restoration successes.
Browse the Publications and Data and Tools tabs to find USGS publications related to invasive annual grasses.
Check out the News tab for plain language descriptions of USGS studies and publications.
Click the Multimedia tab for pictures and maps.
- Science
Visit the team pages for the scientists working on invasive annual grasses.
- Data
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
- Multimedia
Below are downloadable images related to cheatgrass and medusahead.
- Publications
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
Filter Total Items: 35Fungal and bacterial contributions to nitrogen cycling in cheatgrass-invaded and uninvaded native sagebrush soils of the western USA
AimThere is interest in determining how cheatgrass (Bromus tectorum L.) modifies N cycling in sagebrush (Artemisia tridentata Nutt.) soils of the western USA.MethodsTo gain insight into the roles of fungi and bacteria in N cycling of cheatgrass-invaded and uninvaded sagebrush soils, the fungal protein synthesis inhibitor, cycloheximide (CHX), and the bacteriocidal compound, bronopol (BRO) were comAuthorsNicole DeCrappeo, Elizabeth J. DeLorenze, Andrew T Giguere, David A. Pyke, Peter J. BottomleySeventy-five years of vegetation treatments on public rangelands in the Great Basin of North America
On the Ground Land treatments occurring over millions of hectares of public rangelands in the Great Basin over the last 75 years represent one of the largest vegetation manipulation and restoration efforts in the world.The ability to use legacy data from land treatments in adaptive management and ecological research has improved with the creation of the Land Treatment Digital Library (LTDL), a spaAuthorsDavid S. Pilliod, Justin L. Welty, Gordon ToevsFilling the interspace—restoring arid land mosses: source populations, organic matter, and overwintering govern success
Biological soil crusts contribute to ecosystem functions and occupy space that could be available to invasive annual grasses. Given disturbances in the semiarid shrub steppe communities, we embarked on a set of studies to investigate restoration potential of mosses in sagebrush steppe ecosystems. We examined establishment and growth of two moss species common to the Great Basin, USA: Bryum argenteAuthorsLea Condon, David A. PykeSoil moisture and biogeochemical factors influence the distribution of annual Bromus species
Abiotic factors have a strong influence on where annual Bromus species are found. At the large regional scale, temperature and precipitation extremes determine the boundaries of Bromus occurrence. At the more local scale, soil characteristics and climate influence distribution, cover, and performance. In hot, dry, summer-rainfall-dominated deserts (Sonoran, Chihuahuan), little or no Bromus is founAuthorsJayne Belnap, John Thomas Stark, Benjamin Rau, Edith B. Allen, Susan L. PhillipsPlant community resistance to invasion by Bromus species: The roles of community attributes, Bromus interactions with plant communities, and Bromus traits
The factors that determine plant community resistance to exotic annual Bromus species (Bromus hereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in particular ambient and soil temperaturAuthorsJeanne Chambers, Matthew J. Germino, Jayne Belnap, Cynthia Brown, Eugene W. Schupp, Samuel B St. ClairEcosystem impacts of exotic annual invaders in the genus Bromus
An understanding of the impacts of exotic plant species on ecosystems is necessary to justify and guide efforts to limit their spread, restore natives, and plan for conservation. Invasive annual grasses such as Bromus tectorum, B. rubens, B. hordeaceus, and B. diandrus (hereafter collectively referred to as Bromus) transform the structure and function of ecosystems they dominate. Experiments thatAuthorsMatthew J. Germino, Jayne Belnap, John M. Stark, Edith B. Allen, Benjamin M. RauLand uses, fire, and invasion: Exotic annual Bromus and human dimensions
Human land uses are the primary cause of the introduction and spread of exotic annual Bromus species. Initial introductions were likely linked to contaminated seeds used by homesteading farmers in the late 1880s and early 1900s. Transportation routes aided their spread. Unrestricted livestock grazing from the 1800s through the mid-1900s reduced native plant competitors leaving large areas vulnerabAuthorsDavid A. Pyke, Jeanne C. Chambers, Jeffrey L. Beck, Matthew L. Brooks, Brian A. MealorIntroduction: Exotic annual Bromus in the western USA
The spread and impacts of exotic species are unambiguous, global threats to many ecosystems. A prominent example is the suite of annual grasses in the Bromus genus (Bromus hereafter) that originate from Europe and Eurasia but have invaded or are invading large areas of the Western USA. This book brings a diverse, multidisciplinary group of authors together to synthesize current knowledge, researchAuthorsMatthew J. Germino, Jeanne C. Chambers, Cynthia S. BrownLong-term effects of seeding after wildfire on vegetation in Great Basin shrubland ecosystems
1. Invasive annual grasses alter fire regimes in shrubland ecosystems of the western USA, threatening ecosystem function and fragmenting habitats necessary for shrub-obligate species such as greater sage-grouse. Post-fire stabilization and rehabilitation treatments have been administered to stabilize soils, reduce invasive species spread and restore or establish sustainable ecosystems in which naAuthorsKevin C. Knutson, David A. Pyke, Troy A. Wirth, Robert S. Arkle, David S. Pilliod, Matthew L. Brooks, Jeanne C. Chambers, James B. GraceResilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America
Alien grass invasions in arid and semi-arid ecosystems are resulting in grass–fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native ecosystemsAuthorsJeanne C. Chambers, Bethany A. Bradley, Cynthia S. Brown, Carla D'Antonio, Matthew J. Germino, James B. Grace, Stuart P. Hardegree, Richard F. Miller, David A. PykeNitrogen limitation, 15N tracer retention, and growth response in intact and Bromus tectorum-invaded Artemisia tridentata ssp. wyomingensis communities
Annual grass invasion into shrub-dominated ecosystems is associated with changes in nutrient cycling that may alter nitrogen (N) limitation and retention. Carbon (C) applications that reduce plant-available N have been suggested to give native perennial vegetation a competitive advantage over exotic annual grasses, but plant community and N retention responses to C addition remain poorly understooAuthorsDana L. Witwicki, Paul S. Doescher, David A. Pyke, Nicole M. DeCrappeo, Steven S. PerakisEffects of resource availability and propagule supply on native species recruitment in sagebrush ecosystems invaded by Bromus tectorum
Resource availability and propagule supply are major factors influencing establishment and persistence of both native and invasive species. Increased soil nitrogen (N) availability and high propagule inputs contribute to the ability of annual invasive grasses to dominate disturbed ecosystems. Nitrogen reduction through carbon (C) additions can potentially immobilize soil N and reduce the competitiAuthorsMonica B. Mazzola, Jeanne C. Chambers, Robert R. Blank, David A. Pyke, Eugene W. Schupp, Kimberly G. Allcock, Paul S. Doescher, Robert S. Nowak - Web Tools
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
Land Treatment Exploration Tool
The Land Treatment Exploration Tool is designed for resource managers to use when planning land treatments. The tool provides useful summaries of environmental characteristics of planned treatment areas and facilitates adaptive management practices by comparing those characteristics to other similar treatments within a specified distance or area of interest. Provisional Software.
- News
Plain language descriptions for some related USGS products and publications.
New Invasive Annual Grass Book Addresses Critical Questions for the Western U.S.
BOISE, Idaho — Bromus species – such as cheatgrass – are exotic annual grasses that have become the dominant annual grasses in the western hemisphere. Their spread and impacts across the western U.S. continue despite the many attempts by land managers to control these species.Filter Total Items: 16 - Partners