Invasive Medusahead Causes Significant Issues in the US Great Basin

Restoring rangelands degraded by invasive annual grasses has proven to be a difficult task across the western United States Great Basin. A new study in the journal Invasive Plant Science and Management helps identify the role certain plant species can play in the rehabilitation of rangelands, which can improve habitat for wildlife and livestock, along with reducing soil erosion and fire risk.

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Volume 7, Issue 2  (April-June 2014)

Volume 7, Issue 2 (April-June 2014)

This study demonstrates that early-establishing plants may have the ability to suppress exotic invasive grasses and help restore native ecosystems.

(PRWEB) July 07, 2014

Invasive Plant Science and Management—Restoring rangelands degraded by invasive annual grasses has proven to be a difficult task. Even with reseeding help, native species have found it hard to compete with invaders across the western United States Great Basin, an area that includes most of Nevada, and parts of California, Oregon, and Utah. A new study helps identify the role certain plant species can play in the successful rehabilitation of rangelands. Restoring more diverse native plants can improve habitat and forage for wildlife and livestock, along with reducing soil erosion and fire risk.

The study in the current issue of Invasive Plant Science and Management, compares performance of two mixes of native seeds against medusahead, an exotic grass from southwestern Europe which has invaded the Great Basin. Invasive grasses, such as medusahead, decrease native species biodiversity and increase fire frequency.

Two seed mixes of native species, each containing grasses, forbs, and shrubs, were tested for their performance against medusahead. Establishment, above-ground biomass, and seed production of each plant type was measured during the first year of growth. The experiment was conducted in two types of soil—clay loam and sandy loam.

An early seral seed mix containing bristly fiddleneck and squirreltail was more successful in establishing against medusahead, than a late seral seed mix which contains more spring emerging, slower maturing plant species such as gooseberryleaf, globemallow, and Wyoming big sagebrush. The early mix emerged in the fall and contained faster maturing plant species. This early mixture reduced biomass of medusahead plants and seed production by 16 and 17 percent, respectively.

This study demonstrates that early-establishing plants may have the ability to suppress exotic invasive grasses and help restore native ecosystems. This is an important weapon in the arsenal of native species restoration because, as the study also found, medusahead can successfully establish and produce seeds in different soil types. This information may be critical in decreasing potential grass fires in the Great Basin area.

The native annual forb, bristly fiddleneck, was particularly effective against medusahead in both soil types. This study opens the door for future research that can better determine which native species to pit against the invading exotics and what optimal seeding density is needed for bristly fiddleneck and other native plants to suppress medusahead.

Full text of the article “First-year Establishment, Biomass and Seed Production of Early vs. Late Seral Natives in Two Medusahead (Taeniatherum caputmedusae) Invaded Soils,” Invasive Plant Science and Management, Vol. 7, No. 2, April–June 2014, is available at http://www.wssajournals.org/doi/full/10.1614/IPSM-D-13-00068.1.

About Invasive Plant Science and Management:

Invasive Plant Science and Management is a broad-based journal that focuses on invasive plant species. It is published by the Weed Science Society of America, a non-profit professional society that promotes research, education, and extension outreach activities related to weeds; provides science-based information to the public and policy makers; and fosters awareness of weeds and their impacts on managed and natural ecosystems. For more information, visit http://www.wssa.net/.