Eastern prairie fringed-orchid COSEWIC assessment and status report: chapter 14

Technical summary

Platanthera leucophaea

Eastern prairie fringed-orchid – platanthère blanchâtre de l’Est

Range of occurrence in Canada:

Ontario

Extent and area information

Extent of occurrence (EO) (km²)

>20,000 km²

Specify trend in EO :

unchanged

Are there extreme fluctuations in EO?

no

Area of occupancy (AO) (km²)

<10 km²

Specify trend in AO :

decline

Are there extreme fluctuations in AO?

no

Number of extant locations :

20

Specify trend in # more localities are now known due to increased search effort but with habitat loss there is likely an overall decline :

likely some decline

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) :

3-7 years to flowering

Number of mature individuals

>1000

Total population trend:
% decline over the last/next 10 years or 3 generations.

(comparative data are unavailable for nearly half of 20 populations but some, like the Big Creek population have declined by 60-80%) : sizeable declines at some of the larger populations

Are there extreme fluctuations in number of mature individuals?

yes

Is the total population severely fragmented?

yes

List populations with number of mature individuals in each :

Specify trend in number of populations :

increase due to greater search effort

Are there extreme fluctuations in number of populations?

no

Threats (actual or imminent threats to populations or habitats)

  • habitat loss;
  • likely decline in pollinators due to habitat size reduction;
  • successional changes;
  • invasive species;
  • human impacts on water table;
  • natural hybridization;
  • grazing by increased deer population

Rescue effect (immigration from an outside source)

Status of outside population(s)?

USA:

  • SX (extirpated) in MO, NJ, PA;
  • SH (historical) in NY, OK;
  • S1 (critically imperiled) in IA, IL, IN, ME, MI, WA, WI;
  • S2 (imperiled) in OH

Is immigration known or possible?

unknown and unlikely

Would immigrants be adapted to survive here?

possibly

Is there sufficient habitat for immigrants here?

limited

Is rescue from outside populations likely?

no

Quantitative analysis

none

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