Gulf of St. Lawrence aster COSEWIC assessment and status report: chapter 13
Technical summary
Gulf of St. Lawrence Aster
Aster du Saint-Laurent
Range of Occurrence in Canada: Gulf of St. Lawrence, Quebec (Magdalen Islands [MI]), Prince Edward Island (PEI), New Brunswick (NB)
Extent and area information
(Based on GIS calculation of a polygon in which all points at outer limits of range are included.)
(Declines noted in NB and PEI may not be long term trends but may possibly reflect periodic fluctuations due to such significant impacts as major storm events.)
Possibly declining in PEI Fluctuating, possibly declining in NB
(Area of occurrence fluctuates depending on such impacts as major storm events; recent declines noted may reflect temporary changes but this is uncertain.)
Population information
Total: ~12 000 000
Threats (actual or imminent threats to populations or habitats)
- all-terrain vehicles (ATVs) in its habitat (dune slacks); filling of the habitat for construction or development work
- covering of populations with sand during storm events
- high water levels
Rescue effect (immigration from an outside source)
Quantitative Analysis
Not Applicable
Other status
Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Special Concern (1989)
Quebec: Menacée
New Brunswick: Endangered
Prince Edward Island: rare but not officially listed
Status and reasons for designation
Reasons for Designation: An annual halophyte of maritime littoral habitats endemic to the Gulf of St. Lawrence. It is found at nearly 30 extant sites with some very large populations, especially on the Magdalen Islands, but has a very small total area of occupancy of much less than five square kilometres. Many of the populations are subject to natural fluctuations in size and at times suffer important losses due to severe storm events. On-going impacts also exist from human recreational activities and losses of habitat due to development activities.
Applicability of criteria
Criterion A (Declining Total Population): Not Applicable. Declines in NB and PE are relatively small in relation to huge population size in Magdalen Islands; some new populations have also been found in NB and the Magdalen Islands due to increased search effort and the recent losses of populations due to storm events are too recent to recognize as being permanently extirpated since the seeds of the species have a longevity of as much as 10 years.
Criterion B (Small Distribution, and Decline or Fluctuation): Not Applicable. Although possessing small EO and AO there is uncertainty as to whether the populations are severely fragmented due to the plants manner of seed dispersal and the uncertainty, over the long term, of the impact of fluctuating population sizes and the impact of storm events.
Criterion C (Small Total Population Size and Decline): Not Applicable. Total minimum population is too large.
Criterion D (Very Small Population or Restricted Distribution): Threatened under D2 with an area of occupancy <5 km2.
Criterion E (Quantitative Analysis): Not Applicable.
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