Date of Award:

1986

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Advisor/Chair:

Frederick D. Provenza

Abstract

A short duration-high intensity grazing trial was conducted in spring of 1985 to determine whether shrub establishment in crested wheatgrass pastures could be enhanced through spring grazing by cattle, or by fertilization of shrub seedlings. Data was collected on diet selection by cattle during spring grazing, and on subsequent shrub growth and survival. Shrubs studied were transplants of sagebrush, Artemisia tridentata, fourwing saltbush, Atriplex canescens, bitterbrush, Purshia tridentata, and one year old bitterbrush seedlings.

Cattle did not browse sagebrush or fourwing saltbush transplants, but utilization of bitterbrush transplants and seedlings averaged 15 and 42 percent, respectively. Shrub selection by cattle was unaffected by grazing pressure or fertilization.

Fertilization increased growth of sagebrush transplants but had no effect on survival. Trampling of shrubs was greater than anticipated. Trampling reduced growth in sagebrush, and reduced survival of both bitterbrush and sagebrush transplants. Browsing reduced growth of bitterbrush seedlings, but increased growth and survival of bitterbrush transplants. Despite adverse effects from trampling and browsing on some shrubs, the overall effect of spring grazing of crested wheatgrass by cattle was to enhance establishment of fourwing saltbush and bitterbrush transplants. Spring grazing had no measurable effect on establishment of sagebrush transplants or on survival of one year old bitterbrush seedlings.

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