Rangeland inventory or monitoring programs usually concentrate on sampling only a few important species or species groups that serve as indicators of status and/or trend for the entire vegetation. Key species should be selected to satisfy program objectives, such as rare species or important forage plants. This approach permits more efficient sampling and interpretation, because measuring all species is time consuming and often provides greater detail than required.
Because most inventory and monitoring programs have typically evaluated the impact of livestock grazing on rangelands, important forage plants have traditionally been selected as key species. Consequently, when the key species concept is commonly applied to determine utilization levels, selection of plants could vary according to dietary preferences associated with the type of animal using the rangeland and time of sampling. In this situation, the utilization of key species is extrapolated to judge the proper use of other species at the site. Therefore, key species should generally be abundant, productive and palatable components of the vegetation, and moderately sensitive to grazing.
However, key species can be selected to meet any management objective. For example, key species may be chosen in relation to their role in watershed protection, or as threatened or endangered species requiring special attention. Furthermore, if the management goal is to improve low range condition, key species may not be abundant in the existing vegetation, but should still possess a seed source and be known as an indicator of improving range condition.
References and Further Reading
Bureau of Land Management. 1996. Sampling vegetation attributes. Interagency Technical Reference, BLM/RS/ST-96/002+1730. pp 4-5.
Holechek, J.L., Pieper, R.D., and C.H. Herbel. 1995. Range management principles and practices. Prentice Hall, Englewood Cliffs, NJ. 2nd ed. pp 204-205.
Nevada Range Studies Task Group. 1984. Nevada rangeland monitoring handbook. Soil Conservation Service, Forest Service, Bureau of Land Management, University of Nevada Reno, Agricultural Research Service and Range Consultants. September 1984. pp 2-3, 10.
Roberts, B.R., and D.P.J. Opperman. 1974. Veld management recommendations, a reassessment of key species and proper use factors. Proceedings of the Grassland Society of Southern Africa 9:149-155.
Smith, A.D. 1965. Determining common use grazing capacities by application of the key species concept. Journal of Range Management 18:196-201.