Rangeland Ecology & Management

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Rangeland Evaluation

Introduction | General Principles | Sampling Concepts | Vegetation Attributes
Rangeland Evaluation | Management Applications | Chapter Outline

Rangeland evaluation is the process of determining the status of natural rangeland resources. Historically, data describing vegetation attributes is collected by sampling in an inventory and monitoring program. From this information, the status of rangeland vegetation can be rated. Repeated measurements over time provides an indication of whether the vegetation is improving or declining compared to predetermined standards or goals.

Originally, these procedures were developed to offer guidelines for ranch management requirements, such as grazing management, reseeding or brush control. Today, however, public pressure demands more complex assessments based on appropriate ecological standards, in addition to land use demands. Furthermore, a good deal of intuition is required to reconcile interpretations of rangeland assessment with the practical management of livestock or wildlife. For example, a single evaluation provides little information concerning causes of current condition or of appropriate management responses, although the immediate impacts from grazing are often inferred. Even with repeated measurements over time, it is difficult to isolate grazing effects from climatic fluctuations, site variability and sampling error. Approaches that attempt to directly address grazing issues, namely the evaluation of utilization patterns and of carrying capacity, are discussed under Management Implications.

The following sections discuss important concepts associated with conventional methods employed to evaluate the status of rangeland resources, as well as selected initiatives proposed to alleviate weaknesses in the current approaches. Variations adopted by different land management agencies (Natural Resources Conservation Service, Forest Service, and Bureau of Land Management) are not discussed in specific detail, although such inconsistencies represent a major problem when comparing rangelands held under different tenure.

References and Further Reading:

Pearson, H.A., and J.W. Thomas. 1984. Adequacy of inventory data for management interpretations. In: National Research Council/National Academy of Sciences. Developing strategies for rangeland management. Westview Press. pp. 745-763.

Smith, E.L. 1984. Use of inventory and monitoring data for range management purposes. In: National Research Council/National Academy of Sciences. Developing strategies for rangeland management. Westview Press. pp. 809-842.

Task Group on Unity in Concepts and Terminology. 1995. New concepts for assessment of range condition. Journal of Range Management 48:271-282.

West, N.E., McDaniel, K., Smith, E.L., and S. Leonard. 1994. Monitoring and interpreting ecological integrity on arid and semi-arid lands of the western United States. Range Improvement Task Force, Las Cruces, NM. pp. 1-15.