Categories and Criteria
The ecosystem types are assessed on the basis of the categories, criteria and guidelines of the International Union for Conservation of Nature (IUCN). Based on these assessments, the ecosystem types are assigned to different categories that indicate their risk of collapse.
- Innhold
- Categories
- Criteria
Categories
On the basis of the assessments the ecosystem types are classified depending on the degree of their risk of collapse. The ecosystem types are assigned to one of the following eight categories:
Red List Categories
CO Collapsed: An ecosystem type is Collapsed in Norway if there is considerable certainty that it has lost its abiotic and biotic characteristics and the original type has ceased to exist. The ecosystem type is collapsed when it can no longer regenerate naturally.
CR Critically Endangered: An ecosystem type is Critically Endangered when the best available information indicates that at least one of the criteria A to E for being Critically Endangered is met. There is an extremely high risk of collapse for the ecosystem type in Norway.
EN Endangered: An ecosystem type is Endangered when the best available information indicates that at least one of the criteria A to E for being Endangered is met. There is a very high risk of collapse for the ecosystem type in Norway.
VU Vulnerable: An ecosystem type is Vulnerable when the best available information indicates that at least one of the criteria A to E for being Vulnerable is met. There is a high risk of collapse for the ecosystem type in Norway.
NT Near Threatened: An ecosystem type is Near Threatened when the best available information indicates that at least one of the criteria A to E for being near threatened is met. The ecosystem type does not meet any of the criteria A to E for CR, EN, or VU but is close to doing so.
DD Data Deficient: An ecosystem type is assigned to the category Data Deficient when there is considerable uncertainty regarding the correct classification. The possible categories for this ecosystem type range from CR to LC.
Ecosystem types which are assessed as Critically Endangered, Endangered or Vulnerable are all considered to be threatened ecosystem types.
Other categories
LC Least Concern: An ecosystem type is of Least Concern when it does not meet any of the criteria for the categories CR, EN, VU or NT, and is not assigned to the categories DD or NE. The category of Least Concern does not indicate anything about the historic distribution of the ecosystem type, neither does it indicate whether the ecosystem type is undisturbed.
NE Not Evaluated: An ecosystem type is Not Evaluated when it has not been assessed against the Red List criteria. This may be due to very poor data and knowledge, or a lack of available expertise.
The categories Collapsed CO, Critically Endangered CR, Endangered EN, Vulnerable VU, Near Threatened NT and Data Deficient DD comprise the Red List categories. Ecosystem types are of Least Concern LC when declines in the geographic distribution, or the degree of environmental degradation, do not meet the threshold values for red-listing.
Criteria
Red List assessments of ecosystem types in Norway are carried out using five criteria. The method, developed by the International Union for Conservation of Nature (IUCN), emphasizes the objectivity and verifiability of the assessments.
All species are assessed against these five criteria, and the classification is determined by the criterium, or criteria, that indicates the highest risk of collapse for the ecosystem. The assessments against criteria A, B and D are made based on the development of an ecosystem over a 50-year period; the past 50 years, 50 years into the future, or any 50-year period that extends beyond 2018.
The five criteria can be summarized as follows:
A - Reduction in geographic distribution
Reduction in the geographic distribution (total area) of the ecosystem type in the course of a 50-year period.
B - Restricted geographic distribution
B1 The area of distribution (extent of occurence, EOO) and/or B2 number of 10 x 10 km2 grid cells (area of occupancy, AOO) where the ecosystem type currently exists. In addition, at least one of the three subcriteria must be met.
C - Environmental degradation
Proportion of the geographic distribution (total area) that is degraded by abiotic factors and the degree of degradation, in the course of a 50-year period.
D - Disruption of biotic processes and interactions
Proportion of the geographic distribution (total area) that is degraded by the disruption of biotic processes and interactions, and the degree of degradation, in the course of a 50-year period.
E - Quantitative risk analysis
Indicates the estimated probability of collapse for an ecosystem type.
Red List assessments are essentially quantitative. Changes in the area (geographic distribution) of an ecosystem type; how much of the area has disappeared (collapsed) or is degraded; and the degree of degradation, can all be quantified. The threshold values determine the category to which an ecosystem type is assigned. Adequate quantitative information is only available for a minority of ecosystem types, and therefore the assessments must be based on less accurate information combined with the views of experts.
Certain adaptations to the method have been made to suit Norwegian conditions. These are outlined in the Norwegian Red List of Ecosystem Types – Guide to Red List Assessment (Norwegian language only).