THE LIFE-CYCLE OF THE RANGE CONDITION CONCEPT

Recent concerns about range condition measures are not the first concerns about measuring the health of rangelands. To examine why change has not occurred in this area, this paper explores the historical development of the range condition concept in the context of the life cycle of a scientific theory. Dyksterhuis' contribution and significant impact on the concept of range condition reflects the close tie between an underlying ecological theory of the time, that grazing alters species composition in a predictable manner, and his field method which measured that change as the difference between the relative composition of the current and climax vegetation. The evolution of the range condition concept differs in significant ways from the evolution of scientific theories such as Clements' climax theory. These differences include the lack of an intellectual center for research on range condition and reflect the institutionalization of technology to measure range condition. Success of alternative models for range condition may require an underlying theory linked to a field method to successfully capture the consensus of the range community.