Carrying Capacity
Carrying capacity describes the number of grazing animals a management unit is able to support without depleting rangeland vegetation or soil resources. While stocking rates may fluctuate in the short-term in response to fluctuations in the amount and quality of forage, carrying capacity reflects the average level of sustainable production over the long-term.
Determining carrying capacity is a fundamental component of rangeland evaluation, because it is an important management tool that connects forage supply and forage consumption.
Evaluating carrying capacity is an important application of rangeland inventory and monitoring programs, because it represents the key management tool to ensure sustainable use of natural resources. Although carrying capacity is a concept that typically relate to rangeland grazing for livestock production, wildlife considerations are equally relevant under the objectives of conservation and multiple use.
Inventories to determine carrying capacity form the basis of the stocking rate decisions that are particularly important for public land management agencies (eg., Forest Service, and Bureau of Land Management) seeking an objective platform for arbitrating grazing use. Information regarding the carrying capacity of a management unit is also useful for interpreting potential economic returns on ranch developments, such as developing watering points to improve livestock distribution or enhancing wildlife habitat. Moreover, an assessment of carrying capacity forms the basis of ranch value on the real estate market.
Monitoring trends in carrying capacity and stocking rates can often form the basis for changes in livestock management. For example, a decline in carrying capacity is usually interpreted as an indicator of poor resource management and a typical response would be to determine a carrying capacity that would improve range condition.
Although carrying capacity has important implications to management, shortcomings associated with its application should also be recognized. The primary complication in interpreting carrying capacity involves the incorporation of spatial and temporal variability. That is, both forage and animal intake are dynamic factors that vary according to site selection, time of sampling, species composition of the vegetation, utilization patterns, dietary preferences, livestock nutritive requirements, and resources available to the manager. Therefore, an evaluation of carrying capacity should be treated as a preliminary gauge to animal numbers for the management unit that will be revised in the light of monitoring information and immediate forage conditions.
Terminology Related to Carrying Capacity
These are some important terms and concepts related to carrying capacity.
Measurement Techniques and Statistical Analysis
References and Further Reading
Holechek, J.L., R.D. Pieper, and C.H. Herbel. 1995. Range management principles and practices. Prentice Hall, Englewood Cliffs, NJ. 2nd ed. pp. 177-214.
Vallentine, J.F. 1990. Grazing management. Academic Press. San Diego, CA. pp. 294-320.