Productivity refers to the biomass produced at a site over a given period of time. Most vegetation assessments are actually limited to estimating net above-ground primary productivity, by ignoring contributions from consumers (livestock, wildlife, microbial populations, etc.). It also circumvents complicated measurements to account for plant respiration and below-ground contributions.
Productivity is used to indicate energy and nutrient dynamics in the vegetation. Comparisons of productivity from different areas provide an indication of site potential, but in most rangeland areas, moisture availability has the greatest effect on year-to-year fluctuations in productivity.
Sampling date is a critical consideration to obtain reliable estimates of productivity.
References and Further Reading
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Biondini, M.E., Lauenroth, W.K., and O.E. Sala. 1991. Correcting estimates of net primary production: Are we overestimating plant production in rangelands. Journal of Range Management 44:194-198. (pdf)
Daubenmire, R. 1968. Plant communities: A textbook on plant synecology. Harper Row, New York, NY. pp 51-52.
Defosse, G.E., and M.B. Bertiller. 1991. Comparison of four methods of grassland productivity assessment based on Festuca pallescens phytomass data. Journal of Range Management 44:199-203. (pdf)
Holechek, J.L., Pieper, R.D., and C.H. Herbel. 1995. Range management principles and practices. Prentice Hall, Englewood Cliffs, NJ. 2nd ed. pp 135-136.
Martin, M.H., Cox, J.R., and F.F. Ibarra. 1995. Climatic effects on buffelgrass productivity in the Sonoran Desert. Journal of Range Management 48:60-63.