|Johnson, Dustin - Oregon State University|
|Nafus, Aleta - Oregon State University|
Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2015
Publication Date: 5/18/2015
Publication URL: http://handle.nal.usda.gov/10113/60920
Citation: Davies, K.W., Boyd, C.S., Johnson, D.D., Nafus, A.M., Madsen, M.D. 2015. Success of seeding native compared with introduced perennial vegetation for revegetating medusahead-invaded sagebrush rangeland. Rangeland Ecology and Management. 68:224-230. doi: 10.1016/j.rama.2015.03.004.
Interpretive Summary: Medusahead, an exotic annual grass, is invading millions of acres of rangelands. Medusahead can be controlled with prescribed burning followed with a pre-emergent herbicide application. After medusahead control there is a need to establish perennial vegetation to limit re-invasion of medusahead. The success of seeding native compared to introduced perennial vegetation after medusahead control is relatively unknown. We compared seeding native and introduced perennial vegetation after medusahead control with prescribed burning and pre-emergent herbicide application at five sites. Native perennial vegetation generally failed to establish and medusahead was the dominant vegetation by the third year post-seeding. In contrast, introduced perennial vegetation established in high numbers and was limiting medusahead re-invasion. These results suggest that seeding introduced compared to native perennial vegetation is more likely to successfully revegetate medusahead-invaded rangeland after medusahead control.
Technical Abstract: Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle &Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity. Revegetation of medusahead-invaded sagebrush plant communities is needed to restore ecosystem services. Disagreement, however, exists over whether to seed native or introduced perennial species to revegetate communities after controlling medusahead. Though native species generally don’t establish as well as introduced species, interference from co-seeded introduced species has often been attributed to the limited success of natives. Thus, the potential for seeding natives to revegetate communities after medusahead control is relatively unknown because they have been largely co-seeded with introduced species. We compared seeding native and introduced perennial species after controlling medusahead with prescribed burning followed with an imazapic herbicide application at five sites. Perennial bunchgrass cover and density was 5- and 10-fold greater in areas seeded with introduced compared to native species three years post-seeding. In contrast, exotic annual grass cover and density were less in areas seeded with introduced compared to native species. Seeded introduced and native shrubs largely failed to establish. High perennial bunchgrass density (15 individuals•m-2) in areas seeded with introduced species in the third year post-seeding suggests that the succession trajectory of these communities has shifted to becoming perennial-dominated. Average perennial bunchgrass density of 1.5 individuals•m-2 with seeding native species will likely not limit medusahead and appear to already be converting back to exotic annual grass-dominated communities. These results suggest that seeding introduced compared to native species after medusahead control will likely be more successful. Our results also imply that if natives are selected to seed after medusahead control that additional resources may be needed to re-control medusahead and repeatedly sow native species.