Ranking Criteria
Ecological communities are ranked on a global, national and subnational scale of 1 to 5. ACIMS does this using a system similar to the NatureServe conservation ranking. Examples
- G1 (Global 1) indicates that a community is of high conservation concern at the global scale due to rarity, endemism and/or threats.
- G5 (Global 5) indicates that a community is demonstrably widespread and abundant.
- N1 (National 1) or S1 (Subnational 1) indicates that a community is of high conservation concern at the national level.
- S1 (Subnational 1) indicates that a community is of high conservation concern at the state or provincial level.
The two major criteria in determining a community's rank
- Total number of occurrences
- Total area (hectares) of the community range-wide
Additional ranking factors that may be considered when assigning a rank
- Geographic range
- Trends in status - expanding or shrinking range
- Trends in condition - declining condition of remaining hectares
- Threats and fragility
Estimating Ranks
The SRank is provided for all ecological communities on the tracking list. The definition of each rank is provided below. Some ecological communities have been crosswalked with types that are also recognized in the United States. For these, GRanks are also provided.
The criteria used to assign a rank to a particular community are documented using a standardized format: Community ranking attempts to integrate all available information. The amount of information for the ranking factors varies for each community.
- A preliminary ranking is generally necessary as information is usually incomplete.
- Ranks are assigned based on the best available information. They are refined over time.
- Although the methods are standardized, applying conservation ranks to communities is still a subjective process.
- This ranking procedure provides a reasonable estimate of the community rarity. Some degree of error is inherent.
Ecological Community Conservation Ranks
| Rank |
Definition |
| S1 |
- 5 or fewer occurrences or very few remaining hectares.
|
| S2 |
- 6 - 20 occurrences or few remaining hectares.
|
| S3 |
- 21 - 80 occurrences.
- May be rare and local throughout its range or found locally, even abundantly, in a restricted range. Example - e.g. a single county or Natural Sub-region.
|
| S4 |
- Apparently secure province-wide.
- May be quite rare in parts of its range, especially at the periphery.
|
| S5 |
- Demonstrably secure globally province-wide.
- May be quite rare in parts of its range, especially at the periphery.
|
| SNR |
|
| SU |
- Unrankable.
- Currently unrankable due to lack of information or substantially conflicting information about status or trends.
|
| SNA |
- Not Applicable.
- A conservation status rank is not applicable because the community is not a suitable target for conservation activities.
|
| S#S# |
- Ranks can be combined to indicate a range. Example - S2S3 = may be between 6 to 80 occurrences throughout Alberta but the exact status is uncertain.
- Ranges cannot skip more than one rank (e.g., SU is used rather than S1S4).
- Combined ranks indicate a larger margin of error than ranks assigned a "?" qualifier (see below).
|
| Qualifier |
Definition |
| Q |
- Can be added to any global rank to denote questionable taxonomy. Example - G2Q = 6 to 20 known occurrences but questions exist concerning the classification of this type.
- Cannot be used with provincial ranks.
|
| ? |
- Can be added to any rank to denote an inexact numeric rank. Example - S1? = believed to be 5 or less occurrences but some doubt exists concerning status.
|
