Methods to Determine Frequency

There is only one general approach to determining frequency and it is based on identifying key species in each quadrat. It does not require that individuals are distinguished or counted. Therefore, variations of the basic method to determine frequency relate to properties of the sample unit and data manipulation.

Sample Units to Determine Frequency

Frequency data is usually collected using a sample unit with defined boundaries (some type of quadrat) because we need a clearly defined area within which to decide whether the species will be recorded as present.

Data Recording and Calculations to Determine Frequency

References and Further Reading

Bonham, C.D. 1989. Measurements for terrestrial vegetation. John Wiley Son, New York, NY. pp. 90-96.

Despain, D.W., Ogden, P.R., and E.L. Smith. 1991. Plant frequency sampling for monitoring rangelands. In: G.B. Ruyle. (ed). Some methods for monitoring rangelands and other natural area vegetation. University of Arizona, College of Agriculture, Extension Report 9043. pp. 7-25.

Mueller-Dombois, D., and H. Ellenburg. 1974. Aims and methods of vegetation ecology. John Wiley Sons, New York, NY. pp. 72-76.