The degradation of Western rangelands has emerged as a crucial issue in the modern environmental movement. However, despite the contentiousness of the subject, the actual ecology of the situation has been largely overlooked. Ranchers claim to be managing lands appropriately, whereas environmental advocates see grazing as a significant force of degradation. A large part of the debate hinges on the ability to accurately assess the health of Western rangelands.

In this thesis I present a history of the rangeland health assessment system. The assumption of this thesis is that a detailed understanding of the history of rangeland health assessment is a prerequisite for informed debate on the current situation. The assumptions underlying current assessment practice draw heavily on the work of Frederic Clements, an ecological theorist active in the 1920's who believed that nature was both stable and predictable. My thesis analyzes the ways in which these idealized Clementsian theories were originally incorporated into range management, and how they have been modified in the decades since. I parallel ecological history with the history of range management in order to demonstrate that range management has not kept pace with changing science, but has instead relied heavily on outdated theories.

My thesis then analyzes how the theories of Clements have poorly served the modern range manager. A belief in the inherent stability of nature has given both ranchers and environmentalists an incomplete understanding of the actual condition of the land. The assessment of rangeland health is based not in current ecological theory, but in relation to the idealized stable climax proposed by Clements. In the thesis I analyze the ramifications of the specific management practices prompted by Clementsian thinking.

Finally, I consider several suggestions for bringing range management into line with current scientific thinking. I analyze the advantages and drawbacks of several new models of rangeland health assessment and address the problem of translating these models into practice in the field. The debate over Western rangelands has rested on ill-defined terms. In my thesis I wish to vilify or defend neither ranchers nor regulators, but to demonstrate that neither side can accurately argue their position without an understanding of the historical weight of their assumptions.