Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/30/2007
Publication Date: 2/9/2007
Citation: Davies, K.W., Sheley, R.L., Bates, J.D. 2007. Invasibility of Sagebrush-Bunchgrass Communities Four Years Post-Burn [abstract]. Society for Range Management. Paper No.110 Interpretive Summary:
Technical Abstract: Large areas of the Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis (Bettle & A. Young) S.L. Welsh) alliance have been converted to cheatgrass (Bromus tectorum L.) dominated grasslands, particularly in the Intermountain West as a reult of increased wildfire frequencies. However, the invasibility of prescribed burned, late seral Wyoming big sagebrush-bunchgrass communties by cheatgrass after an initial recovery period has not been investigated. Treatments were fall prescribed burned (burned)four growing seasons prior to introducing cheatgrass and not burned (control). Cheatgrass was broadcast seeded at 10,000 seeds * m-2 in each of the six treatment replications. Cheatgrass density and cover, soil water, soil inorganic nitrogen, and herbaceous cover, density, and biomass were compared between treatments. Cheatgrass density was bout 300 % higher in the control than burned treatment (P<0.05). Soil inorganic nitrogen was also higher in the control compared to the burned treatment (P<0.05). Herbaceous biomass, density, and cover were higher in the burned than control treatment (P<0.05). Soil water content and cheatgrass cover was not different between treatments (P>0.05). Our results suggest that prescribed burning of late seral sagebrush communities can increases their long-term resistance to cheatgrass invasion. The increase in herbaceous vegetation following the prescribed burn probably decreased the susceptibility of the community to cheatgrass invasion. Our result may have been drastically different if cheatgrass would have been introduced to the area immediately after prescribed burning, herbaceous vegetation had experienced long-term negative impacts from burning, or the community had been in a lower seral stage prior to burning. Plant communities that evolved with infrequent disturbances may need disturbances to maintain ecosystem integrity.