How the Red List is compiled
The Norwegian Biodiversity Information Centre compiles the Red List of Species in cooperation with a wide range of experts from scientific institutions and individuals with special expertise. The assessments for this edition of the Red List were made by 19 expert committees with a total of 94 members.
- Which species are evaluated?
Species are evaluated against a set of criteria developed by the International Union for Conservation of Nature (IUCN). The criteria and guidelines for using them ensure that evaluations are standardised, verifiable and objective. All species are evaluated against the following five criteria:
A. Population size reduction (past, present and/or projected)
B. Geographic range size, and fragmentation, few locations, decline or fluctuations
C. Small and declining population size, and fragmentation, fluctuations, or few subpopulations
D. Very small population or very restricted distribution
E. Quantitative analysis of extinction risk
The criteria are used to assign species to one of the categories shown below. The categories reflect the level of risk that a species will go regionally extinct if conditions remain unchanged. Species in the categories Critically Endangered (CR), Endangered (EN) and Vulnerable (VU) are described as threatened species.
Which species are evaluated?
All species, as well as subspecies and varieties in vascular plants and mosses, can be considered for the Norwegian Red List if they meet one of the intitial requirements:
- Is a native species documented or assumed to have an established reproducing population in Norway. A population is considered established reproducing if more than 20 individuals reproduce* in Norway over more than 10 consecutive years in the period 1800-2021.
- Is an alien species that is documented or assumed to be established reproducing in Norwegian nature before year 1800, i.e., is natualized. Alien species established after the year 1800 are not evaluated for the Red List, but assigned to the category Not Applicable.
- Is a visiting species, defined as a species in which more than 2 % of the global population regularly visits Norway (such as migrating and overwintering species).
* Completes the entire reproductive cycle or any essential part of it within Norway, per the definition of breeding population in the IUCN Guidelines for Application of IUCN Red List Criteria at Regional and National Levels, version 4.0.