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field_methods:estimate_population_size

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Estimate of Population Size

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

Similar Approaches

Additional Information

field_methods/estimate_population_size.1253571620.txt.gz · Last modified: 2012/02/22 13:28 (external edit)