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Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/16/2010 Publication Date: 9/22/2010 Citation: Davies, K.W. 2010. Revegetation of medusahead invaded sagebrush steppe. Rangeland Ecology and Management. 63:564-571 Interpretive Summary: Medusahead is an exotic annual grass invading western rangelands. Revegetation of medusahead invaded plant communities is needed to increase livestock forage production and improve wildlife habitat. This study evaluated herbicide (imazapic) application, prescribe burning, and their combinations at controlling medusahead and promoting seeded bunchgrasses. Medusahead was best controlled when prescribed burned and then treated with imazapic. Prescribed burning followed by imazapic application treatments also had greater large perennial bunchgrass cover and density compared to other treatments. The results of this study question the long-term effectiveness of using imazapic in revegetation efforts of medusahead infested sagebrush steppe without first prescribed burning the infestation. Effective control of medusahead appears to be needed for establishment of seeded perennial bunchgrasses. The results of this study demonstrate that seeding bunchgrasses can successfully revegetate rangeland infested with medusahead when medusahead has been controlled with prescribed fire followed by fall application of imazapic. Land managers will find this information useful to revegetate plant communities that have been invaded by medusahead and other exotic annual grasses. Technical Abstract: Medusahead (Taeniatherum caput-medusae (L.) Nevski) is an exotic annual grass invading western rangelands. Invasion by medusahead is especially problematic because it decreases livestock forage production, degrades wildlife habitat, reduces biodiversity, and increases fire frequency. Revegetation of medusahead invaded plant communities is needed to increase ecosystem and economic productivity. However, most efforts to revegetate medusahead infested plant communities are unsuccessful because perennial bunchgrasses rarely establish after medusahead control. The effects of prescribed burning (spring or fall), fall imazapic application, and their combinations were evaluated for medusahead control and the establishment of seeded large perennial bunchgrasses. One growing season after treatments were applied desert wheatgrass (Agropyron desertorum (Fisch. ex Link) Schult.) and squirreltail (Elymus elymoides (Raf.) Swezey) were drill seeded into the treatment plots, except for the control treatment. Vegetation characteristics were measured for two years post-seeding (2nd and 3rd year post-treatment). Medusahead was best controlled when prescribed burned and then treated with imazapic (P < 0.05). These treatments also had greater large perennial bunchgrass cover and density compared to other treatments (P < 0.05). The prescribed burned followed by imazapic application treatments had greater than 10- and 8-fold more perennial bunchgrass cover and density than the control treatment, respectively. Prescribed burning, regardless of season, was not effective at controlling medusahead or promoting establishment of perennial bunchgrasses. The results of this study questions the long-term effectiveness of using imazapic in revegetation efforts of medusahead infested sagebrush steppe without first prescribed burning the infestation. Effective control of medusahead appears to be needed for establishment of seeded perennial bunchgrasses. The results of this study demonstrate that seeding desert wheatgrass and squirreltail can successfully revegetate rangeland infested with medusahead when medusahead has been controlled with prescribed fire followed by fall application of imazapic. |
