Red crossbill, percna subspecies (Loxia curvirostra) recovery strategy: appendix 1
APPENDIX 1
Threat Classification Table
| Stress | Threata | Causal certaintyb | Timing | Frequency | Extent | Severityb | Level of concernb | ||
|---|---|---|---|---|---|---|---|---|---|
| Local | Range-wide | Local | Range-wide | ||||||
| Reduced population | C: Habitat loss or degradation G: Habitat disease S: White pine blister rust / Scleroderris canker |
Medium | Medium | Historic/ current | Continuous | Widespread | High (1) | High | High |
| Reduced population | C: Habitat loss or degradation G: Fire S: Forest fire |
High | Low | Historic/ current | Recurrent | Localized | High | Low | Low |
| Reduced population | C: Habitat loss or degradation G: Insects S: Tree loss |
High (2) | Medium (2) | Historic/ current | Continuous | Widespread | High | Unknown (3) | Medium |
| Reduced population | C: Exotic species G: Food competition S: Red squirrels |
Medium (5) | Medium (5) | Current | Continuous | Widespread | Unknown | Unknown | Medium |
| Reduced population | C: Natural processes G: Nest predation S: Interspecific nest predation (jays and squirrels) |
Low | Low | Current | Seasonal | Widespread | Unknown | Unknown | Low |
| Reduced population | C: Habitat loss or degradation G: Fire suppression S: Forest conversion |
High | Low | Current/ anticipated | Seasonal | Localized | High | Low | Low |
| Reduced population | C: Habitat loss or degradation G: Spruce budworm S: Reduced cone production |
High | High | Historic/ anticipated | One-time | Widespread | High (4) | High (4) | High |
| Reduced population | C: Habitat loss or degradation G: Loss of forest cover S: Urbanization |
Medium | Low | Current/ anticipated | Continuous | Localized | Medium | Low | Low |
| Reduced population | C: Habitat loss or degradation G: Loss of forest cover S: Agricultural expansion |
Medium | Low | Current/ anticipated | Continuous | Localized | Medium | Low | Low |
| Reduced population | C: Habitat loss or degradation G: Forestry S: Commercial harvest |
High | Low (6) | Historic/ current | Continuous | Widespread | High | Unknown | High |
| Reduced population | C: Habitat loss or degradation G: Forestry S: Domestic harvest |
Medium | Low | Historic/ current | Continuous | Widespread | Medium | Low | Low |
| Reduced population | C: Natural processes G: Not applicable S: Allee effect |
Low | Low | Current/ anticipated | Continuous | Widespread | Unknown | Unknown | Medium (7) |
| Reduced population | C: Natural processes G: Interspecific competition S: Seed-eating finches |
Low | Low | Current/ anticipated | Continuous | Widespread | Unknown | Unknown | Medium (7) |
| Cumulative effects | All, some, or many of the above |
||||||||
a C = threat category; G = general threat; S = specific threat.
b Qualifiers:
1 – High if eastern white pine is deemed important.
2 – This may need to be revisited if an insect is discovered to impact red pine.
3 – Severity is dependent upon the effectiveness of monitoring and control programs.
4 – Dependent upon Red Crossbill food preference.
5 – In areas of black spruce.
6 – Dependent upon forestry statistics to indicate management practices of forests to ensure perpetual availability of viable habitat for Red Crossbills.
7 – Level may change if research indicates that there is an increased level of importance for this threat.
APPENDIX 1.1
Clarification of terms used in Threat Classification Table. [1]
Potential threat categories:
- Habitat loss or degradation
- Consumptive use
- Pollution
- Exotic species
- Modification of natural processes
- Changes in ecological dynamics
- Accidental mortality
- Disturbance and persecution
- Climate and natural disasters
- Natural processes and activities
Potential causal certainty categories:
- High – Evidence causally links the threat to stresses on population viability.
- Medium – The correlation between the threat and population viability is derived from expert opinion.
- Low – Considered a putative or plausible threat only.
Potential timing categories:
- Historic – Likely contributed to population declines, but is no longer affecting the species.
- Current – Is likely affecting the species at the present time.
- Imminent – Is expected to affect the species in the near future unless mitigation is undertaken.
- Anticipated – May affect the species in the future.
- Unknown – Unknown if factor has affected or will affect the species.
Potential frequency categories:
- One-time occurrence
- Seasonal – Either because the species is migratory or the threat occurs only at certain times of the year
- Continuous – Ongoing
- Unknown
Potential severity categories:
- High – Very large population effect expected.
- Medium – Intermediate population effect expected.
- Low – Very low population effect expected.
[1]The list of categories below is representative of all potential categories. Not all categories listed below are used in the table.