WDC50: Ecology and Management of Invasive Grasses in Western Rangelands

(Multistate Research Coordinating Committee and Information Exchange Group)

Status: Active

WDC50: Ecology and Management of Invasive Grasses in Western Rangelands

Duration: 10/01/2019 to 09/30/2021

Administrative Advisor(s):

NIFA Reps:

Statement of Issues and Justification

Rangelands of the western U.S. are impacted by numerous stressors that affect their ability to provide ecosystem goods and services for society. Fire, energy development, exurban subdivision, the transportation network, climate variability, and changes in land use are all examples of disturbances that can impact rangeland vegetation, and often exacerbate the spread of invasive weed species. It is difficult to disentangle invasive grasses from these stressors because their establishment and spread is facilitated by altered disturbance regimes.

Invasive grasses pose a particularly difficult management challenge: how do land managers selectively remove a grassy weed from systems largely comprised of desirable grasses? Detecting, identifying, and mapping relatively cryptic grass species within a ‘sea’ of other grasses is more difficult than large, showy, flowering plants. Negative impacts of invasive grasses are not as intuitive to some landowners because they may view them as another source of forage, although data indicate their forage production is highly variable among years and not dependable.

Cheatgrass (Bromus tectorum) alone is estimated to impact over 100 million acres of western rangelands. Few other invasive plant species have such a broad ecological extent. Ventenata (Ventenata dubia) and medusahead (Taeniatherum caput-medusae) are rapidly expanding their range and colonizing habitats previously not impacted by cheatgrass. In the Southwest, species such as Lehmann lovegrass (Erogrostis Lehmanianna) and buffelgrass (Pennisetum cilare) outcompete valuable native forage grasses and increase fire frequency. Species previously considered ‘crop weeds,’ such as jointed goatgrass (Aegilops cylindrica), are now invading rangelands. Already a prominent resource concern by the early 1940s, the invasive grass issue continues to become more complex and difficult to manage.

Recent developments in ecological understanding, available technology, and government policies may make successful long-term, landscape-scale management a reality. A coordinated effort, integrating research, education, and outreach,  is needed to enhance communication among western states to tie together related research programs focused on ecology and management of invasive grasses in rangelands.

Justification for forming a Multistate Research Project: Invasive grasses impact rangelands across the western U.S. The extent and severity of the issue necessitates that research spans ecoregions and operates at landscape scales. Formation of a Multistate Research Project will facilitate co-created experimental design and implementation among states to better elucidate regionally-specific differences in ecology and treatment efficacy and patterns that are consistent across ecoregions that may be broadly adaptable. Example projects that this group may pursue include: 1) reciprocal transplant or common garden studies across the region to better understand how local adaptation leads to higher invisibility or improved restoration success and 2) evaluation of management practices dispersed across a wide geography to elucidate consistency of approaches under diverse climatic and invasion conditions.

Potential duplication in efforts in existing committees:  The most similar western regional Multistate Project is WERA77 – Managing Invasive Weeds in Wheat. While some of the species of focus overlap, the proposed WDC will focus on rangelands, forests, and natural areas – all sufficiently different from wheat production systems that a different approach and ecological underpinning for invasive grass management is needed. Additionally, management practices in wheat systems are often not available or incompatible with management regimes in natural rangeland ecosystems.

The committee will work on the following objectives as they develop a full proposal. 


  1. Increase knowledge around basic biology and ecology of species that drives invasion across the west
  2. Apply invasive plant ecology principles to managing invasive grasses in rangelands
  3. Further develop detection and monitoring networks for new invasive grass populations
  4. Increase communication and cooperation among land grant universities and research partners (government agencies, landowners, NGOs, etc.) in the West
  5. Decrease the science-practice gap around managing invasive grasses
  6. Conduct collaborative research to strengthen our ability to manage one of the most impactful natural resource issues in the western U.S.

Procedures and Activities

Expected Outcomes and Impacts

Projected Participation

View Appendix E: Participation

Educational Plan


Literature Cited


Land Grant Participating States/Institutions


Non Land Grant Participating States/Institutions

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