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Publication Information

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Title: No safety in numbers

Author: Beissinger, Steven R.; Flather, Curtis H.; Hayward, Gregory D.; Stephens, Philip A.;

Date: 2011

Source: Frontiers in Ecology and the Environment. 9: 486.

Publication Series: Scientific Journal (JRNL)

Description: Clements et al. (Front Ecol Environ 2011; 9[9]: 521-525) proposed a single metric that describes a "species' ability to forestall extinction" (referred to by the acronym "SAFE") as a "scientifically defendable rule of thumb for when complete demographic data are unavailable" to rank the relative threat status of a species. SAFE is calculated on a logarithmic scale and reflects the difference between a species' current population size and 5000, the estimate for a universal minimum viable population (MVP) promoted by Traill et al. (2010). Clements et al. advocated SAFE as a useful tool for triage to allocate resources in conservation, and as a measure of population viability that would be more easily understood by the public than the IUCN Red List categories (Mace et al. 2008). We believe that SAFE is not a useful metric to guide conservation planning for three main reasons.

Keywords: species' ability to forestall extinction (SAFE), minimum viable population (MVP)

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.



Beissinger, Steven R.; Flather, Curtis H.; Hayward, Gregory D.; Stephens, Philip A. 2011. No safety in numbers. Frontiers in Ecology and the Environment. 9: 486.


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