Changes in species status
One of the important achievements of this report is to update the status assessments of taxonomic groups that were included in previous Wild Species reports. Among the taxonomic groups that were reassessed in this report, a total of 626 species had a change in their Canada rank.
In total, 15% of the changes involved species moving into a rank with an increased level of risk (95 changes, table 42), 27% involved species moving into a rank with a reduced level of risk (166 changes), and 16% involved species moving into or out of the Undetermined, Not Assessed, Exotic or Accidental ranks (102 changes). Updates have also resulted in the addition of 162 new species to the national list (26% of the changes). Just as importantly, 101 species have been removed from the national list (16% of changes). Updating the national species lists in this way keeps the General Status program and the Wild Species series abreast of the latest scientific knowledge.
Most of these changes were due to improved knowledge of the species (table 43). This reason accounted for more than half of all the changes observed in the Canada ranks. Taxonomic changes, biological changes, and changes due to new COSEWIC detailed assessments also accounted for an important part of the reasons of the changes.
Table 42. Changes (n = 626) in the level of risk for species in taxonomic groups that were reassessed in the Wild Species 2010 report.
| Taxonomic group | Number of species with increased level of risk | Number of species with reduced level of risk | Number of species changed from/to ranks 5, 6, 7, or 8* | Number of new species | Number of deleted species |
|---|---|---|---|---|---|
| Vascular plants | 54 | 132 | 84 | 131 | 94 |
| Freshwater mussels | 4 | 1 | 2 | 0 | 1 |
| Odonates | 1 | 14 | 6 | 3 | 1 |
| Tiger beetles | 3 | 1 | 0 | 1 | 0 |
| Butterflies | 3 | 13 | 3 | 11 | 2 |
| Crayfishes | 0 | 0 | 0 | 0 | 0 |
| Amphibians | 1 | 1 | 0 | 1 | 0 |
| Reptiles | 4 | 1 | 0 | 1 | 0 |
| Birds | 23 | 1 | 4 | 12 | 1 |
| Mammals | 2 | 2 | 3 | 2 | 2 |
| TOTAL | 95 (15%) |
166 (27%) |
102 (16%) |
162 (26%) |
101 (16%) |
* Note: 5 = Undetermined, 6 = Not Assessed, 7 = Exotic, 8 = Accidental.
Table 43. Summary of the reasons for changes in the status of species between the last assessment and the current report.
| Code | Description | Number of species | Proportion of all changes |
|---|---|---|---|
| B | Change due to biological change in species' population size, distribution or threats. | 63 | 10% |
| C | Change due to new COSEWIC assessment. | 64 | 10% |
| E | Change due to error in previous ranks. | 10 | 2% |
| I | Change due to improved knowledge of the species. | 343 | 54% |
| P | Change due to procedural changes. | 16 | 3% |
| T | Taxonomic change. | 130 | 21% |
| TOTAL | 626 | 100% |