Skip to main content
SLU publication database (SLUpub)

Research article2010Peer reviewedOpen access

A method for inferring extinction based on sighting records that change in frequency over time

Jaric Ivan, Ebenhard Torbjörn


It is a very important, but also a very difficult task, to establish how long a certain species has to remain unregistered before we can declare it extinct. The wrong assumption regarding species extinction could result in a type I or type II statistical error, leading to inappropriate management actions or even species extinction. Recent development of the methods for inferring the threat of extinction, when the only available information is a record of sightings, has enabled a quantitative approach to the problem. In our study we present an index that infers extinction probability based on trends in sighting intervals. Our study comprises a description of the sighting trend index, a sensitivity analysis and an application of the index to the sighting record of the black-footed ferret Mustela nigripes. The main advantage of this method could be its sensitivity to changes in sighting frequency within the sighting record. However, further testing of the method on different data sets could be important for gaining additional knowledge regarding its adequate application in the field of conservation biology


black-footed ferret; extinction probability; modelling; Mustela nigripes

Published in

Wildlife Biology
2010, Volume: 16, number: 3, pages: 267-275

    Associated SLU-program

    SLU Swedish Biodiversity Centre

    Sustainable Development Goals

    SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss

    UKÄ Subject classification

    Environmental Sciences related to Agriculture and Land-use

    Publication identifier


    Permanent link to this page (URI)