Degree Name

Master of Science

Document Type

Thesis

Date Created

8-2021

Department

College of Natural and Health Sciences, Biological Sciences, Biological Sciences Student Work

Abstract

Cattle grazing has influenced the environment in the western United States since European settlement in the 1800’s. Continuous and heavy grazing on arid and semi-arid rangelands has resulted in decreased biodiversity, changes in vegetation structure, and vulnerability to exotic plant invasion. Heavy grazing has also been linked to decreased cryptobiotic soil due to trampling and susceptibility to erosion. With a lack of effective means of successful habitat restoration, there is a rising concern among land managers to maintain these intricate systems, notably under the threat of climate change. Consequently, there is a critical need to understand these system’s response to grazing pressure and resilience once released from such pressure, especially on a long-term scale. To address this problem, we studied various attributes (i.e., cryptobiotic soil, vegetation, and soil properties- among seven exclosure locations on the rangeland of Capitol Reef National Park, Utah. These exclosures were built in the 1980’s, were monitored for six years, and have not been observed since initial monitoring from 1984-1989. We found observable differences when comparing inside versus outside the exclosures under a variety of grazing histories. Treatment differences included percent ground cover, vegetation trends, soil stability, and cryptobiotic soil attributes. Additionally, we found significant changes in these attributes over time. One of the more notable changes was that of significant increase in cryptobiotic soil cover over all treatments across the park. Finally, we found that drought may have an overarching, greater influence over rangeland communities than grazing or grazing history. Future long-term research on arid/semi-arid landscapes should further examine the relationship of vegetation and cryptobiotic soil under both heavy grazing regimes and long-term drought conditions. Greater understanding of these changes on disturbed lands, especially under the threat of climate change, will better equip land managers to make sustainable and successful landscape decisions.

Keywords

Cattle grazing; Rangelands; Colorado Plateau; Capitol Reef National Park; Cryptobiotic soil; Long-term resilience

Rights Statement

Copyright is held by the author.

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