User Tools

Site Tools


field_methods:estimate_population_size

Report a bug, broken link, or incorrect content

Estimate of Population Size


written by Jason Karl

Method Type

Abundance - Qualitative

Other Names

Estimated population count, population estimate

Description and Uses

This technique involves making rapid assessments of the number of individuals in a population at a site by visual estimate. A quick, gross indicator of the size of a population, this technique can sometimes be used for coarse assessments of population trends over time if the change is large. Often, population size can be estimated while collecting presence/absence data. The establishment of protocols and size classes can help remove some of the subjectivity of this method and increase repeatability. Size and visibility of the plants being counted need to be considered as this method breaks down if many individuals are not detected.

Advantages and Limitations

The main advantage of this method is that it is a quick way to collect information on population abundance. The disadvantages to this method are:

  1. it is highly subjective and repeatability is low
  2. there can be a large amount of variation between observers
  3. cryptic species or those difficult to see due to surrounding vegetation can cause significant underestimation.

Manuals/Instructions

Technical and Application References

  • Muir, P. S. and R. K. Moseley. 1994. Responses of Primula alcalina, a threatened species of alkaline seeps, to site and grazing. Natural Areas Journal 14: 269-279.

Similar Approaches

Quantitative estimates of population size can be obtained using frequency or density methods like [quadrat frequency], [nested frequency], or [density quadrats].

Additional Information

Web Search Results

Loading...
Loading...

Discussion/Comments

You must have an account and be logged in to post or reply to the discussion topics below. Click here to login or register for the site.

field_methods/estimate_population_size.txt · Last modified: 2012/03/08 15:34 by jgillan