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Overview
Conservation status ranks are assigned to Elements at the global, national and subnational levels. Elements added to the Alberta Conservation Information Management System (ACIMS) database are assigned Subnational Ranks (S-Ranks) for Alberta according to NatureServe Methodology. S-Ranks are calculated using the NatureServe Rank Calculator.
S-Ranks can be calculated for all types of Elements, including species, subspecies, and ecological communities.
Conservation status ranks
Assigning conservation status ranks
The process of assigning S-Ranks involves integrating all available data on an Element, to provide a picture of the Element’s conservation status. The data available can vary widely between Elements.
Although methods are standardized, ranking Elements with low data availability involves uncertainty. In some cases, there is not enough data to assign a rank, in other cases a range of ranks is provided to reflect uncertainty regarding the status of the Element (see Table 2, below). Ranks are assigned based on the best available information and are refined over time.
NatureServe ranking methodology
The NatureServe ranking methodology involves assessing the conservation status of an Element. Up to 8 rank factors can contribute to rank calculation:
- Range extent
- Area of occupancy
- Population size
- Number of occurrences
- Number of occurrences with “Good” viability
- Long term trend
- Short term trend
- Threats (severity, scope, impact and timing)
The data is analyzed using the NatureServe Rank Calculator and S-Ranks are calculated. These calculated ranks must be reviewed and accepted by an expert.
- Learn more about NatureServe Conservation Status Assessment, where the NatureServe Rank Calculator can also be downloaded.
Species Elements
Most S-Ranks in the ACIMS database for species Elements are assigned through the General Status of Wild Species process by taxonomic experts. Through this process, taxonomic experts compile lists of species reported for Alberta and calculate their S-Ranks using NatureServe methodology and rank calculator.
Vertebrate species
For status ranking of vertebrate species in Alberta – for example, mammals, birds, fish, reptiles, amphibians – also check the General status of Alberta wild species.
Ecological community Elements
Historically, a committee on ecological communities would meet at regular intervals to review and update S-Ranks. Many ecological communities in Alberta are under sampled, making them difficult to rank.
Rank definitions
Subnational conservation status ranks (S-Ranks)
Table 1. Standard S-Rank abbreviations and definitions (adapted from NatureServe*).
| Rank | Definition |
|---|---|
| SX | Presumed extirpated – Element is believed to be extirpated from the province. Not located despite intensive searches of historical sites and other appropriate habitat. Virtually no likelihood that it will be rediscovered. |
| SH | Possibly extirpated – known from only historical records but still some hope of rediscovery. Evidence that the taxon may no longer be present but not enough to state this with certainty. |
| S1 | At very high risk of extirpation in the jurisdiction due to very restricted range, very few populations or occurrences, very steep declines, severe threats, or other factors. |
| S2 | At high risk of extirpation in the jurisdiction due to restricted range, few populations or occurrences, steep declines, severe threats, or other factors. |
| S3 | At moderate risk of extirpation in the jurisdiction due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors. |
| S4 | At a fairly low risk of extirpation in the jurisdiction due to an extensive range and/or many populations or occurrences, but with possible cause for some concern as a result of local recent declines, threats, or other factors. Taxon is uncommon but not rare. |
| S5 | Taxon is common, widespread, and abundant. Very low or no risk of extirpation in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. |
Variant Subnational Ranks
Table 2. Variant S-Rank abbreviations and definitions.*
| Rank | Definition |
|---|---|
| S#S# | Range rank – A numeric range rank is used to indicate a range of uncertainty about the status of the taxon. Example, S2S3 or S1S3. Ranges cannot skip more than 2 ranks. Example, SU is used rather than S1S4. |
| SU | Unrankable – Taxon is currently unrankable due to lack of information or substantially conflicting information. Example, native versus non-native status not resolved. |
| SNR | Unranked – Conservation status not yet assessed. |
| SNA | Not applicable – A conservation status rank is not applicable because the species or ecosystem is not a suitable target for conservation activities. Example, introduced species or hybrid without conservation value. |
Subnational qualifiers
Table 3. Subnational qualifier rank abbreviation and definition.*
| Qualifier | Definition |
|---|---|
| S#? | Inexact numeric rank – Applied when a specific rank is most likely appropriate but for which some conflicting information or unresolved questions remain. |
Subnational breeding status qualifiers
Table 4. Subnational breeding status qualifier abbreviation and definition.*
| Rank | Definition |
|---|---|
| B | Breeding – Conservation status refers to the breeding population of the Element. |
| N | Non-breeding – Conservation status refers to the non-breeding population of the Element. |
| M | Migrant – Migrant species occurring regularly in the jurisdiction, which may warrant conservation attention. Conservation status refers to the aggregating transient population of the species. |
* NatureServe. 2025. Conservation Status Categories. NatureServe, Arlington VA. Available at https://explorer.natureserve.org/AboutTheData/DataTypes/ConservationStatusCategories. (Accessed: 2025-03-20).
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