Wood-poppy (Stylophorum diphyllum) COSEWIC assessment and status report: chapter 11

Technical Summary

Stylophorum diphyllum

Wood-poppy – Stylophore à deux feuilles

Range of Occurrence in Canada:
southern Ontario

Extent and Area Information

Extent of occurrence (EO)(km²):
150 km²
Specify trend in EO :
stable
Are there extreme fluctuations in EO?
no
Area of occupancy (AO)
[Actual area occupied by the three populations is <1 ha] :
3 km²based on a 1x1 km grid overlay and 12 km² based on a 2x2 km grid
Specify trend in AO :
decline
Are there extreme fluctuations in AO?
no
Number of known or inferred current locations :
3
Specify trend in # :
stable
Are there extreme fluctuations in number of locations?
no
Specify trend in area, extent or quality of habitat :
decline

Population Information

Generation time (average age of parents in the population):
5 years
Number of mature individuals :
~530
Total population trend:
Major decrease followed by stable or slight increase
 % decline over the last/next 10 years or 3 generations.
~35%
Are there extreme fluctuations in number of mature individuals?
no
Is the total population severely fragmented?
yes
Specify trend in number of populations :
stable
Are there extreme fluctuations in number of populations?
no

List populations with number of mature individuals in each:

London:
~250
Fanshawe:
24
Ilderton:
255

Threats (actual or imminent threats to populations or habitats)

  1. Habitat destruction and modification
  2. Development
  3. Invasive species
  4. Seed predation
  5. Trespass and recreation
  6. Genetic contamination
  7. Trampling
  8. Collection

Rescue Effect (immigration from an outside source)

Status of outside population(s)? USA:
[other jurisdictions or agencies] :
See Table 1

Is immigration known or possible?
not known, very unlikely
Would immigrants be adapted to survive in Canada?
yes
Is there sufficient habitat for immigrants in Canada?
yes
Is rescue from outside populations likely?
no

Quantitative Analysis

n/a

Current Status

COSEWIC: Endangered (2000, 2007)

MNR: Endangered

Status and Reasons for Designation

Status: Endangered

Alpha-numeric code: Endangered B1ab(iii)+2ab(iii)

Reasons for Designation: A showy perennial herb of Carolinian woodlands restricted to 3 small and highly fragmented populations occupying very limited areas. The habitat is declining in quality due to the presence of invasive plants and habitat disruption due to recreational activities that increase the risk of trampling. Further potential habitat disruption may occur with the expansion of housing development and other commercial activities adjacent to two of the sites. The species is widely available from nurseries but garden-grown plants cultivated in Canada likely originate from U.S. stocks. Cultivated plants are not included in the COSEWIC assessment.

Applicability of Criteria

Criterion A (Declining Total Population): Threatened A2ace A 35% decline in populations in under 3 generations and continuing decline in habitat quality with ongoing threats from invasive exotic plants and other factors.

Criterion B (Small Distribution, and Decline or Fluctuation): Endangered B1ab(iii)+2ab(iii) EO and AO below limits for endangered and only 3 severely fragmented locations with continuing decline in quality of the habitat.

Criterion C (Small Total Population Size and Decline): Threatened C2a(i) No population with >1000 mature individuals but nearly meeting endangered with only 1 population barely exceeding 250 mature individuals.

Criterion D (Very Small Population or Restricted Distribution): Threatened D1+2<1000 mature individuals and only 3 populations with an AO <20 km².

Criterion E (Quantitative Analysis): None available.

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