Definitions and delimitations

• Innhold
• Do the assessments cover all species in Norway?
• What does 'known in Norway' mean?
• What does 'estimated number' of species mean?
• Species numbers in terms of environment type
• How is knowledge status defined?
• Knowledge status report Picture and dowload

An overview of the most important definitions and delimitations follows. Further information (Norwegian language only) is available in the Knowledge Report (Elven and Søli 2016).

Do the assessments cover all species in Norway?

The assessments include native species (naturally reproducing in Norway), regular guests and vagrants, as well as alien species that have become established to some degree, outside cultivated areas. Alien species that do not reproduce outside cultivated areas have been excluded.

In the Norwegian Biodiversity Information Centre's Species Nomenclature Database (Artsnavnbasen), there are registrations of many species that do not reproduce outside cultivated areas. This applies in particular to vascular plants. The Species Nomenclature Database also contains species that have become extinct. The number of known species in the Knowledge Report therefore deviates from the number of species registered in the database.

In a few cases the number of species and knowledge status on the website of the Norwegian Biodiversity Information Centre deviates from the numbers in the Knowledge Report (Elven and Søli 2016). This is due to new assessments being made after the completion of the report.

What does 'known in Norway' mean?

The term 'known' is used when stating the number of species. 'Known in Norway' means that there is documentation that the species has been found on Norwegian territory (with the exception of Norwegian territory in Antarctica). This documentation can be, for example, an article in a publication or a specimen in a public or private collection.

What does 'estimated number' of species mean?

For every species group the estimated number of species is assessed. This figure comprises the number of known species as well as an estimate of the number of unknown species in Norway. This last figure comprises species that we believe currently exist in Norway but which have not yet been discovered. This can include undiscovered species in poorly surveyed species groups, species that have recently come to Norway, or new species that may be discovered through genetic studies.

There is often considerable uncertainty concerning the estimate of undiscovered species. For some poorly studied species groups, such as sporozoans, ciliates and many groups of microalgae and macroalgae, the number of unknown species is not estimated at all. The estimated number of species in Norway is therefore an estimated minimum number.

Species numbers in terms of environment type

For most of the groups, the numbers of known species in saltwater, freshwater and terrestrial environments have been provided. A source of uncertainty is that many species can be difficult to assign unambiguously to one of these environments. This applies to species that inhabit brackish water, species that can be found in more than one environment, and species that spend different phases of their life-cycle in different environments. Species that can be found in more than one environment have been assigned to that environment type in which they have their most important ecological role i.e. where the majority of the population exist or where the majority of their life cycle is spent. Species that cannot be assessed in this way have been divided between the relevant environment types. Parasites have been assigned on the basis of the environment in which the host lives.

How is knowledge status defined?

Knowledge status is assessed separately for each of the parameters of taxonomy, distribution and ecology. For some superior taxa that lack knowledge status assessments, the report editors (Hallvard Elven and Geir Søli) have suggested an assessment. These estimates are based on the specialists' assessment of the sub-levels and are stated in parentheses in the tables presented under each kingdom. A detailed description of how these estimates are calculated is available in the Knowledge Report (Norwegian language only).

The knowledge status for taxonomy, distribution and ecology is assessed using 6 grades.

Taxonomy

No knowledge (0) The taxonomy of the group has not been clarified for the species groups that are found in Norway

Very poor knowledge (1) The taxonomy of the group is very poor for the species groups that are present in Norway. Nomenclature is unstable at the species level. Unclarified synonyms and/or unclear species delimitations are common and contribute considerably to uncertainty about the number of species in Norway.

Poor knowledge (2) The taxonomy of the group is generally poor for the species groups that are present in Norway. Nomenclature is generally unstable at the species level. Unclarified synonyms and/or unclear species delimitations contribute to uncertainty about the number of species in Norway.

Acceptable knowledge (3) The taxonomy of the group is generally satisfactory for the species that are present in Norway, and nomenclature is relatively stable at the species level. Unclarified synonyms and/or unclear species delimitations nonetheless contribute in many cases to uncertainty about the number of species in Norway.

Good knowledge (4) The taxonomy of the group is predominantly good for the species groups that are present in Norway. Nomenclature is stable at the species level. Species delimitation is predominantly good and there are at most only a handful of undescribed species in Norway.

Definite knowledge (5) The taxonomy of the group is complete for the species that are present in Norway. Nomenclature is stable both at the species level and higher taxonomic level. Species delimitation is good and it is most unlikely that new species will be described in Norway.

Distribution

No knowledge (0) We know little or nothing about the distribution of known species in Norway.

Very poor knowledge (1) The knowledge of the distribution of known species in Norway is generally very poor. For the majority of species there are only sporadic finds that give little insight into the total distribution.

Poor knowledge (2) The knowledge of the distribution of known species in Norway is unsatisfactory. There are a considerable number of species where we only have sporadic finds that give little insight into the total distribution.

Acceptable knowledge (3) The distribution of known species in Norway is reasonably well known. For the majority of species we have general knowledge about their total distribution in Norway but we often lack detailed knowledge about populations within the area of distribution.

Good knowledge (4) The distribution of known species in Norway is generally well known. For the majority of species we have detailed knowledge about the area of distribution in Norway but individual populations within the area of distribution may be unknown.

Definite knowledge (5) The distribution of known species in Norway is known with certainty. It is highly unlikely that there are any unknown populations.

Ecology

No knowledge (0) Nothing is known about the ecology of known species in Norway. We have no knowledge or minimal knowledge about their ecological niche, behaviour, and interaction with other organisms.

Very poor knowledge (1) The knowledge of the ecology of known species in Norway is very poor. In general, we lack essential knowledge about their ecological niche, behaviour, and interaction with other organisms.

Poor knowledge (2) The knowledge of the ecology of known species in Norway is unsatisfactory. For the majority of species we lack important knowledge about their ecological niche, behaviour, and interaction with other organisms.

Acceptable knowledge (3) The ecology of known species in Norway is relatively well known but we still have many unanswered questions with regard to their ecological niche, behaviour, and interaction with other organisms.

Good knowledge (4) The ecology of known species in Norway is quite well known. We have satisfactory knowledge about the ecological niche and behaviour of known species, and their interaction with other organisms.

Definite knowledge (5) The ecology of known species in Norway is very well known. We have reliable knowledge about the ecological niche and behaviour of known species, and their interaction with other organisms. 

Categories 0 – 5 for taxonomy, distribution and ecology, are first and foremost most suitable for use with homogenous species groups i.e. groups where there is little variation in the level of knowledge within the group. For more heterogenous groups, the contributors have, to a greater degree, exercised some discretion in making the assessments. As a guideline, categories 0 – 2 have been used for species groups where the knowledge level is, on average, less than satisfactory, while categories 3 – 5 are used to indicate a level of knowledge that is, on average, satisfactory or better.