Application of Lessons Learned from NRCS Rangeland CEAP: A site-specific, Low Cost System for Medusahead Control

Over the course of this project, we have developed decision support tools, produced technical guides on low-cost medusahead management, and implemented demonstration projects on ranches that were be used as the basis for workshops and the development of peer-learning networks.

Decision Support Products

We have published a paper that analyzes the body of scientific knowledge on the effectiveness of practices to reduce medusahead dominance in both the intermountain west and the California annual grassland with a meta-analysis approach, “Managing medusahead (Taeniatherum caput-medusae) on rangeland: A meta-analysis of control efforts and assessment of stakeholder needs” (James et al 2015). This paper distills the body of knowledge as it exists in a variety of papers into one analysis that assesses the effects of practices (including grazing, fire, herbicide, mowing, and seeding) individually and in combination with respect to their effectiveness 1 and 2 to 3 years after implementation to help compare and clarify what the benefits of each alternative practice are.

We have published two papers (Brownsey et al. 2016a, Brownsey et al. 2016b) that analyze the susceptibility of medusahead and barb goatgrass to grazing and mowing treatments and related this to phenological stages with data on the timing of these stages to help inform range managers with targeting the precise timing when either of these two treatment tools would be most effective at achieving the goal of reducing abundance of barb goatgrass or medusahead.

We have presented a several talks and workshops on treating medusahead and barb goatgrass, how one chooses treatment options and the costs-benefits of IPM approaches, including initial findings on the effect of medusahead abundance on livestock production in weight gain terms.

Demonstration Ranch Projects

At the Glenn County demonstration ranch we collected data to evaluate the effectiveness of broadcast seeding on a 330 acre pasture. Using these data we will be comparing vegetation composition and productivity on this pasture to a comparable 380 acre pasture on the same property. This area was substantially affected by the recent drought and there is the possibility of investigating whether this kind of seeding strategy may also serve as a post-drought recovery practice, as well.

At the Stanislaus County demonstration ranch we assessed the effects of drill seeding annual ryegrass and targeted grazing on livestock production, vegetation composition, and forage production. At this site we also continued to work with the rancher to develop an IPM strategy for managing medusahead. Implementing this strategy, we broadcast seeded and harrowed three 25 to 30 acres with annual ryegrass in the fall of 2015. We will be comparing vegetation composition, productivity, and animal performance on these pastures to two comparable, adjacent 25 and 30 acre pastures on the same property. In the spring of 2015, all five of these pastures werel be grazed with randomly assigned stocker cattle at the same stocking rates to measure grazing days as well as cattle weight gains, and this will be integrated with other work on the effects of vegetation composition on steer performance to further illuminate our understanding of the benefits of rangeland seeding treatments. In the fall of 2016, the same pastures at this ranch were broadcast seeded with annual ryegrass with pasture harrowing in an effort to contrast the relative costs and benefits of this method with using a seed drill.

Both demonstration ranches in Oregon were photo-sampled in July to track changes in vegetation composition and medusahead abundance. These ranches were significantly affected by drought during the past year. At the Grant County demonstration ranch, fall targeted grazing on medusahead was conducted for a second consecutive year using supplement blocks to manage livestock distribution. At the Crook County demonstration ranch, water improvements were completed to allow greater flexibility in grazing management, including improved livestock distribution for increased grazing on medusahead.

Peer-Learning Networks

We have hosted four field workshops for ranchers and land managers, reaching about 60 people. In these workshops, we outlined approaches to medusahead management and discussed our experiences implementing practices at the demonstration ranches while also providing a venue for ranchers and land managers to share their experiences managing medusahead. An additional two field workshops are planned at the Oregon demonstration ranches.

In an effort to better understand how ranchers and rangeland managers access and use information on invasive plant management to make management decisions, we conducted face-to-face semi-structured interviews with private ranchers and people with rangeland management responsibilities for public lands and landtrusts (UC Davis IRB ID 773400-1). We selected initial interviewees based on existing contacts with University of California Cooperative Extension Livestock Advisors and used these initial interviewees to inform the selection of further interviewees using a snowball technique, until we reached 43 interviews. These interviewees were dispersed geographically from Tehama to Fresno County, roughly encompassing the extent of medusahead invasion in annual rangeland in California. These interviews will provide information on how best to address the information needs of ranchers and rangeland managers as well as how best to deliver advice based on best available research so that it can be incorporated into decision-making. These interviews will also assess the adoption of current research and identify real or perceived barriers to adoption of effective treatment practices.

Measuring Ecosystem Services

To measure the correlation between medusahead abundance and provision of several ecosystem services from rangelands, we set up a series of observational plots across the state, from Tehama to Monterey County. At a total of 28 plots, we have measured vegetation composition—including medusahead abundance—and insect community composition in the spring and early summer of 2015 and 2016. Similar data is being collected at the Stanislaus County demonstration site. Following the arthropods collections in 2015, we have cataloged 9,000 specimens from about 76 families. These plots will provide information to begin to form hypotheses on the effects of medusahead on vegetation diversity arthropod diversity, abundance of beneficial and pest arthropods, and forage production. Analysis and publication of these results is ongoing.

At an additional 5 sites (Tehama, Yuba, Stanislaus, and Contra Costa Counties), we are testing the relationship between medusahead abundance and nitrogen cycling by comparing plots of differing initial levels of medusahead by tracking stable isotopes of nitrogen added to the plots in the fall of 2015 before germination and again mid-winter before the rapid growth period of spring. Analysis and publication of these results is ongoing.