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Research article - Peer-reviewed, 2010

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

Authors' information

Jaric, Ivan
Swedish University of Agricultural Sciences, Swedish Biodiversity Centre

Sustainable Development Goals

SDG15 Life on land

UKÄ Subject classification

Environmental Sciences related to Agriculture and Land-use

Publication Identifiers


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