The Saskatchewan Conservation Data Centre is responsible for evaluating and assigning a conservation rank to each taxon, resident or transient, found in the province. The process of conservation ranking involves the review of information housed in the SKCDC database as well as scientific and government literature, natural history publications, consultations with recognized experts and highly knowledgeable amateur naturalists as well as field work. The goal of this process is to arrive at a subnational or S-rank, based on the best available information, that best characterizes the extirpation risk of an element in the province. This subnational or S-rank serves to focus conservation concerns.
Ranks are calculated using a standardized procedure set forth by NatureServe, which allows the SKCDC to follow a standardized, repeatable, and transparent procedure for categorizing the province’s flora and fauna.
Each species assessment considers not just rarity, but also trends and threats:
A minimum number of factors, and a minimum of certain types of factors, are needed to calculate a rank. The factors are scaled and weighted according to their impact on risk, and points are used to score the contribution of each factor to the risk. The final overall score is equated with a rank.
Ranks are given as the letter that represents the geographic scale followed by a number that represents the taxon’s risk of extirpation. A higher S-rank (e.g., S5) indicates that a species is more common, more stable, and less threatened than a species with a lower S-rank (e.g., S1), which would indicate that a species is rarer, declining, facing a high threat level, or a combination of these factors.
1 |
Critically Imperiled/ Extremely rare | At very high risk of extinction or extirpation due to extreme rarity, very steep declines, high threat level, or other factors. |
2 |
Imperiled/Very rare | At high risk of extinction or extirpation due to a very restricted range, very few populations, steep declines, threats, or other factors. |
3 |
Vulnerable/Rare to uncommon | At moderate risk of extinction or extirpation due to a restricted range, relatively few populations, recent and widespread declines, threats, or other factors. |
4 |
Apparently Secure | Uncommon but not rare; some cause for long-term concern due to declines or other factors. |
5 |
Secure/Common | Demonstrably secure under present conditions; widespread and abundant; low threat level. |
A range rank (such as S3S4) is used when the taxon straddles the criteria for more than one rank (i.e., S3 and S4). Letters in the rank are referred to as modifiers and can have various meanings:
| A - | accidental or causal in the province, including species recorded infrequently that are far outside their range (birds and butterflies) |
| B – | for a migratory species, applies to the breeding population in the province |
| N – | for a migratory species, applies to the non-breeding population in the province |
| M – | for a migratory species, rank applies to the transient (migrant) population |
| H – | historical occurrence of the taxon, without recent verification (e.g., 20-40 years or older) |
| U – | status is uncertain in Saskatchewan because of limited or conflicting information (unrankable) |
| X – | believed to be extinct or extirpated from the province |
| NR – | rank is not yet assigned, or species has not yet been assessed (not ranked) |
| NA – | conservation status is not applicable to the species (e.g., it may have been determined to have been introduced in Saskatchewan) |
A “?” following a rank means that there is some uncertainty associated with it. For example, a rank of S3? means that it is believed to be most likely an S3, but there is a significant chance that it could be an S2 or S4.
The SKCDC prioritizes taxa for ranking based on a five-year rotation. Information on each taxon is gathered and compiled prior to assessing the rank factors. Once a rank is calculated, it is reviewed by SKCDC staff and other experts (e.g., members of the Botanical Assessment Working Group for plants), and can be adjusted if the reviewers feel that it is necessary. The ranks are only as good as the information that is put into the calculator, so it is important for the SKCDC to have all the most up-to-date information on a taxon before ranking it. External data may play a role in adjusting the rank, but, if possible, the SKCDC will incorporate such data into its database prior to the rank calculation.
Where data is scarce, the SKCDC may rely on expert opinion to inform a conservation rank.
Why are these ranks important? Conservation activities are focused on taxa that have a rank of S1, S2 or S3. Taxa with a rank including S3 or less are tracked by the SKCDC and locations of conservation significance are mapped. Locations of these species are made available through websites such as HABISask for uses that include project planning of developments on the landscape. Taxa that are not ranked S1, S2 or S3 may still be tracked if special circumstances warrant.
Species conservation rankings (S-Ranks) can be found in any of the SKCDC's species lists.
Many of the subnational and national conservation ranks in the SKCDC’s database have been assessed/reassessed as a result of the General Status of Species in Canada program. The National General Status Working Group, comprised of government representatives as well as Conservation Data Centre specialists and ex officio members, contracts experts to review the statuses of specific taxon groups. These taxon groups can include any wild species – bees, flowers, slime molds, you name it! Every five years, the General Status of Species in Canada program releases a Wild Species report that provides a snapshot of the status of wild species in Canada.
These reports can be downloaded from the Wild Species website.
