Date of Award:

8-2021

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Committee Chair(s)

Kari E. Veblen

Committee

Kari E. Veblen

Committee

Eric Thacker

Committee

Thomas A. Monaco

Abstract

Approximately 10-20% of global dryland ecosystems are severely degraded, an amount that is expected to increase, threatening the environment and ecosystem services that 38% of the global population relies upon. Human activities such as agriculture, livestock grazing, mining and urban development have contributed to the degradation and loss of rangelands worldwide. A need for reestablishing sagebrush in disturbed landscapes across the Western United States, including dryland pastures, has been identified but traditional, primarily seeding-based, restoration methods have largely been unsuccessful. To improve restoration outcomes, there has been increased interest in the planting of containerized greenhouse “tubelings”, but transplanting of mature plants, “wildlings”, remains relatively unexplored. Survival of tubelings vs. wildlings and under what conditions these techniques might be suitable are unclear. Here we tested establishment of mountain big sagebrush (A. tridentata ssp. vaseyana) from planting tubelings vs. wildlings. Research was conducted in southeastern Idaho where vegetation was dominated by two non-native grasses which are a concern for land managers. Following seedbed preparation and application of herbicide, the study area was drill-seeded with a mix of rangeland grasses and forbs. We then established thirty-six research plots, each of which received one of three sagebrush establishment methods: tubelings vs. wildlings, plus seeding for comparison over the long term. Another six plots were established as controls (no sagebrush). In addition to assessing planting quality and frost heaving at the time of planting, we recorded plant survival the summer and fall after planting, as well as other measures such as percent green leaves present, plant height, physical damage, and reproduction. Survival of wildlings one year after planting was significantly higher than that of tubelings (92% and 17% respectively). Tubeling mortality had a significant association with the poor planting variable (e.g., exposed roots or air pockets in the soil), indicating that quality of planting performed by vegetation crews needs to be more closely examined. The results of this study illustrate that wildlings can yield very high one-year survival rates (especially compared to tubelings) and suggest that, when conditions are appropriate, wildlings may be a more cost-effective method for establishing sagebrush.

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