Management of the annual grass medusahead is needed in rangelands because it is an invasive species. Medusahead competes with desired grasses and flowering plants for nutrients, forms a dense mat that prevents establishment of desired species, and increases the risk of wildfire.
Systematic research reviews identify patterns of management success across multiple research studies. Reviews of this type, however, may not yield the specific information needed by wildland managers. UCCE Specialist and Affiliated IPM Advisor Jeremy James sought to do both.
James, Cooperative Extension’s Joe DiTomaso, Josh Davy, Morgan Doran, Theresa Becchetti, David Lile, and Philip Brownsey, and UC Davis researchers Elise Gornish and Emilio Laca conducted a systematic review of medusahead IPM. James then compared his review results with an assessment of stakeholder needs to identify critical knowledge gaps in medusahead management.
The systematic review covered research published from 1960 to 2013. Twenty-two studies assessed how IPM combinations of herbicides, burning, seeding, and grazing impacted medusahead on rangeland dominated by either annual or perennial vegetation. All combinations for both annual and perennial vegetation provided significant short-term control of medusahead.
Medusahead competes with desired grasses and flowering plants for nutrients, forms a dense mat that prevents establishment of desired species, and increases the risk of wildfire.
James also convened a group of over 93 stakeholders to assess their management information needs. Stakeholders listed grazing as a preferred IPM tool. James’s systematic review determined on annual rangeland an almost 2-fold reduction in medusahead abundance by stocking the area with high numbers of livestock, such as sheep or cattle, at the same time when medusahead is most susceptible to defoliation. Insufficient data was available to evaluate the effects of grazing on medusahead on perennial rangeland.
Based on the systematic review and stakeholder survey, four major information needs emerged:
James’s systematic review increased the understanding of key knowledge gaps and economic constraints that limit adoption of IPM practices by stakeholders. Knowing the gaps means research can be targeted to better understand this lack of information. Through the systematic review, public land managers and conservation groups have a synopsis of management results from all recent research, rather than having to distill it themselves from numerous research papers and presentations. It is expected that making science-based management guidance easier to understand will result in an increase in end users who use these IPM practices.