Lakeside daisy (Hymenoxys herbacea) COSEWIC assessment and update update status report: chapter 11
Technical Summary
Hymenoxys herbacea
Lakeside Daisy – Hyménoxys herbacé
Extent and Area Information
Extent of occurrence:
75,246 km²
Area of occupancy:
about 14 km²
Population information
Total number of individuals in the Canadian population:
471 million rosettes (ramets)
Number of mature reproducing individuals in the Canadian population:
> 6.8 million flowering rosettes
Generation time:
16 years (mean age at which new plants produce offspring)
Total population trend:
unknown, but some populations known to be declining
Rate of decline for total population:
- ____% in 10 years or three generations,
- _____ % decline in ____ years.
Number of known populations:
39 in Canada
Is the total population fragmented?
Yes
number of individuals in smallest population:
50 rosettes
number of individuals in largest population:
202,013,200 rosettes
number of extant sites:
38
number of historic sites from which species has been extirpated:
1
Does the species undergo fluctuations in numbers?
not significantly
If yes, what is the
- maximum number? ______
- minimum number? ______
Are these fluctuations greater than one order of magnitude?
No
Threats
Habitat destruction (quarry activity, cottage construction, human traffic and trampling), habitat availability.
Rescue Effect
Does the species exist outside of Canada?
Yes
Is immigration known or possible?
No? ~ 0.6 migrants/generation among Canadian populations. Migration rate between Canadian and U.S. populations unknown, but highly unlikely. The two isolated U.S. populations are separated by large water bodies from suitable habitat in Canada. This species does not disperse well and propagules would be unlikely to reach suitable habitat from U.S. populations
Would individuals from the nearest foreign population be adapted to survive in Canada?
Probably
Would sufficient suitable habitat be available for immigrants?
Yes, at least on Manitoulin Island and the Bruce Peninsula
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