White wood aster (Eurybia divaricata) COSEWIC assessment and status report: chapter 12
TECHNICAL SUMMARY
| Eurybia divaricata (L.) Nesom | |
White wood aster Heart-leaved aster |
aster divariqué |
| Occurrence in Canada: | Ontario and Quebec |
| Extent and Area information | ||
| · extent of occurrence (EO)(km²) | <1500 | |
| · specify trend (decline, stable, increasing, unknown) | In Ontario, populations appear to be stable presently but have declined in the past. Infrequent data collection for populations in Quebec makes it hard to predict trends. | |
| · are there extreme fluctuations in EO (> 1 order of magnitude)? | No | |
| · area of occupancy (AO) (km²) | <50 | |
| · specify trend (decline, stable, increasing, unknown) | Stable | |
| · are there extreme fluctuations in AO (> 1 order magnitude)? | No | |
| · number of extant locations | 25 | |
| · specify trend in # locations (decline, stable, increasing, unknown) | Increase in reported number of locations in Ontario. Increase in reported number of locations in Quebec. |
|
| · are there extreme fluctuations in # locations (>1 order of magnitude)? | No | |
| · habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitat | Unknown | |
| Population information | ||
| · generation time (average age of parents in the population) (indicate years, months, days, etc.) | Unknown | |
| · number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values) | 8000-9000 individuals in scattered populations | |
| · total population trend: specify declining, stable, increasing or unknown trend in number of mature individuals | Stable | |
| · if decline, % decline over the last/next 10 years or 3 generations, whichever is greater (or specify if for shorter time period) | ||
| · are there extreme fluctuations in number of mature individuals (> 1 order of magnitude)? | No | |
| · is the total population severely fragmented (most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange, i.e., < 1 successful migrant / year)? | Yes | |
| · list each population and the number of mature individuals in each | See Tables 1 & 2 | |
| · specify trend in number of populations (decline, stable, increasing, unknown) | Increasing | |
| · are there extreme fluctuations in number of populations (>1 order of magnitude)? | No | |
| Threats (actual or imminent threats to populations or habitats) | |
| - Habitat destruction | |
| - Invasive species | |
| - Browsing by deer | |
| - Weevil predation | |
| - Trampling | |
| · does species exist elsewhere (in Canada or outside)? | Yes |
| · status of the outside population(s)? | Stable |
| · is immigration known or possible? | Not known |
| · would immigrants be adapted to survive here? | Possibly |
| · is there sufficient habitat for immigrants here? | Possibly |
| Quantitative Analysis | |
Page details
- Date modified: