Author
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Submitted to: Weed Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/19/2007 Publication Date: 5/1/2008 Citation: Sheley, R.L., Bates, J.D. 2008. Restoring western juniper infested rangeland after prescribed fire. Weed Science. 56:469-476. Interpretive Summary: Restoring range sites dominated by Juniperus occidentailis is central to maintaining healthy functioning shrub-steppe ecosystems. On sites without adequate species composition to respond favorably to juniper control, revegetation is necessary. We tested the hypotheses that the highest density of native desired species seeded after control of J. occidentalis using fire would occur at the highest seeding rate, and seeding a rich mixture of species would provide densities and biomass equal to or greater than species seeded as monocultures. Treatments were applied in 2003, which was one year following 100% J. occidentailis removal using a cut and burn procedure. Treatments included seeding six native species in monocultures, seeding a mixture of all six species at four rates (16.8, 22.4, 28.0, or 33.6 kg/ha of pure live seeds), and a nonseeded control applied on a Sagebrush/wheatgrass and Snowberry/fescue site. We found that Agropyron spicatum, Festuca idahoensis, Poa ampla, Achillea millifolium, and Linum perenne density ranged from 450 to 700 plants/m2, which was over 6-fold that of the control in 2004 at both sites. The density of P. ampla nearly doubled by 2005. Among the grasses, the highest plant density always resulted from seeding a rate higher than the lowest rate (16.8 kg/ha). The only response of forbs was that seeding 16.8 kg/ha produced the highest density of L. perrene. The density of the seeded species in plots where a combination of species were seeded essentially mimicked the pattern of those sown as monocultures, but tended to optimize plant diversity and richness. Technical Abstract: Restoring range sites dominated by Juniperus occidentailis is central to maintaining healthy functioning shrub-steppe ecosystems. On sites without adequate species composition to respond favorably to juniper control, revegetation is necessary. We tested the hypotheses that the highest density of native desired species seeded after control of J. occidentalis using fire would occur at the highest seeding rate, and seeding a rich mixture of species would provide densities and biomass equal to or greater than species seeded as monocultures. Treatments were applied in 2003, which was one year following 100% J. occidentailis removal using a cut and burn procedure. Treatments included seeding six native species in monocultures, seeding a mixture of all six species at four rates (16.8, 22.4, 28.0, or 33.6 kg/ha of pure live seeds), and a nonseeded control applied on a Sagebrush/wheatgrass and Snowberry/fescue site. We found that Agropyron spicatum, Festuca idahoensis, Poa ampla, Achillea millifolium, and Linum perenne density ranged from 450 to 700 plants/m2, which was over 6-fold that of the control in 2004 at both sites. The density of P. ampla nearly doubled by 2005. Among the grasses, the highest plant density always resulted from seeding a rate higher than the lowest rate (16.8 kg/ha). The only response of forbs was that seeding 16.8 kg/ha produced the highest density of L. perrene. The density of the seeded species in plots where a combination of species were seeded essentially mimicked the pattern of those sown as monocultures, but tended to optimize plant diversity and richness. |
