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Vegetation Characteristics Of Wyoming Big Sagebrush Communities Historically Seeded With Crested Wheatgrass In Northeastern Great Basin, Usa, Justin Rodney Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) is one of the most commonly seeded grass species in the western United States and dominates thousands of hectares in the Great Basin. Although many degraded Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) plant communities have been seeded with crested wheatgrass, successional pathways, influence of soil attributes, and cultivation history on the vegetation of these communities have not been fully characterized. I sought to identify community phases, vegetative differences, and soil attributes that explain variation among 35 Wyoming big sagebrush communities historically seeded with crested wheatgrass. All communities were more than …

Seed Banks Of Sagebrush Communities Seeded With Crested Wheatgrass, Kevin L. Gunnell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) is one of the most commonly seeded exotic species in the western United States. Although many degraded Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) plant communities have been seeded with crested wheatgrass during rehabilitation efforts, seed banks of these communities have not been characterized. I sought to characterize and explain the variation among 33 seeded communities in the northeastern Great Basin. Hierarchical clustering and principal components analysis identified four possible seed bank categories in these communities. Seed bank categories varied from high to low crested wheatgrass dominance. The crested wheatgrass-dominated category …

Impact Of Root Competition On Survival And Growth Of Seedlings Of Important Great Basin Species, Günther Reichenberger

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Belowground competition is pronounced in the arid Great Basin sagebrush ecosystem. Plant demographic and root exclusion approaches were used to examine the influence of roots of adult Artemisia tridentata, Agropyron desertorum, and Agropyron spicatum individuals on seedling survival of Ar. tridentata, Ag. desertorum, Ag. spicatum, and Bromus tectorum. Furthermore, growth rates of Ar. tridentata seedlings and seed production of B. tectorum were assessed.

The probability of a seedling being alive versus dead significantly depended on the seedling species, the neighboring adult species, and on the depth to which root competition was excluded. As seedlings, …