Dwarf hackberry (Celtis tenuifolia) COSEWIC assessment and status report: chapter 12
Technical Summary
Celtis tenuifolia
Dwarf hackberry – micocoulier rabougri
Range of Occurrence in Canada:
Ontario
Extent and Area Information
Extent of occurrence (EO) (km²)
Based on polygon around sites, excluding the large area between the southwestern and eastern Ontario populations. <5000 km²
Specify trend in EO :
Stable
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km²)
Based on an approximation of habitats occupied. <20 km²
Specify trend in AO :
Stable
Are there extreme fluctuations in AO?
No
Number of known or inferred current locations :
6
Specify trend in # :
increase, but likely reflecting old populations not previously known vs. expansion
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat :
Stable
Population Information
Generation time (average age of parents in the population) :
several decades
Number of mature individuals :
893 (based on counts and additional estimates)
Total population trend: Stable
% decline over the last/next 10 years or 3 generations.
N/A
Are there extreme fluctuations in number of mature individuals?
No
Is the total population severely fragmented?
Ontario populations and others at northern range widely separated
Specify trend in number of populations :
Slow increase based on new discoveries of old sites
Are there extreme fluctuations in number of populations?
No
List populations with number of mature individuals in each:
- Pelee Island: 5
- Point Anne: 2
- Point Pelee: 136
- Sterling Slope: 24
- Ipperwash-Pinery: 724
- Lonsdale: 2
Threats (actual or imminent threats to populations or habitats)
- Bark beetles (10% mortality/year: Dunster, 1992).
- Loss of habitat through limestone quarrying, sand extraction and cottage development.
Rescue Effect (immigration from an outside source)
Status of outside population(s)?
USA: Imperilled, vulnerable to apparently secure.
Is immigration known or possible?
Possible, via migratory birds
Would immigrants be adapted to survive in Canada?
Yes, if from northern populations
Is there sufficient habitat for immigrants in Canada?
Yes
Is rescue from outside populations likely?
Possible but unlikely
Quantitative Analysis
N/A
Current Status
COSEWIC: Threatened
Status and Reasons for Designation
Status: Threatened
Alpha-numeric code: Met criteria for Endnagered, B1ab(iii,v)+2ab(iii,v) but was designated Threatened, B1ab(iii,v)+2ab(iii,v); C2a(i)’ D1_2. because it is not at imminent risk of extirpation.
Reasons for Designation: A shrub of dry sandy or calcareous alvar woodlands habitats found at only six disjunct and fragmented sites adjacent to the Great Lakes. Fewer than 1000 plants have been documented. Threats include potential loss of habitat due to quarrying operations and sand pit expansion in eastern Ontario sites and significant losses in some years due to beetle infestations.
Page details
- Date modified: