Verna's flower moth (Schinia verna) COSEWIC assessment and status report: chapter 12

Technical Summary

Schinia verna

Verna’s Flower Moth – Héliotin de Verna

Canadian population : Southeastern Alberta, west-central Saskatchewan and southwestern Manitoba

Extent and Area information

extent of occurrence (EO)km²):
128,000 km² maximum
specify trend (decline, stable, increasing, unknown) :
probably declining due to habitat loss
are there extreme fluctuations in EO (>1 order of magnitude)?
unknown
area of occupancy (AO) (km²):
16,000 km² maximum, but very likely <2000 km²
specify trend (decline, stable, increasing, unknown) :
probably declining due to habitat loss
are there extreme fluctuations in AO (> 1 order magnitude)?
unknown
number of extant locations :
1 known
specify trend in # locations (decline, stable, increasing, unknown) :
unknown
are there extreme fluctuations in # locations (>1 order of magnitude)?
unknown
habitat trend:  specify declining, stable, increasing or unknown trend in area, extent or quality of habitat :
probably declining

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.) :
one year
number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values) :
unknown
total population trend: specify declining, stable, increasing or unknown trend in number of mature individuals :
unknown
if decline, % decline over the last/next 10 years or 3 generations, whichever is greater (or specify if for shorter time period) :
N/A
are there extreme fluctuations in number of mature individuals (>1 order of magnitude)?
probably
is the total population severely fragmented (most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange, i.e., < 1 successful migrant / year)?
unknown
list each population and the number of mature individuals in each:
Jenner, AB – # unknown
specify trend in number of populations (decline, stable, increasing, unknown) :
unknown
are there extreme fluctuations in number of populations
(>1 order of magnitude)?
unknown

Threats

Loss of native grassland habitat

Rescue Effect (immigration from an outside source)None
does species exist elsewhere (in Canada or outside)?
Not known outside Canada
status of the outside population(s)?
N/A
is immigration known or possible?
N/A
would immigrants be adapted to survive here?
N/A
is there sufficient habitat for immigrants here?
probably

Quantitative Analysis

insufficient data

Current Status

COSEWIC: Threatened (May 2005)

Status and Reasons for Designation

Status: Threatened

Alpha-numeric code: B2ab(iii)

Reasons for Designation: This moth is found only in the Canadian prairies, with one extant site in southeastern Alberta. The species is known historically from very few locations despite its relatively large size, distinctive markings and day-flying habit. It has a small total range in suitable native prairie that is fragmented and declining in quality and extent.

Applicability of Criteria

Criterion A (Declining Total Population): Insufficient information

Criterion B (Small Distribution, and Decline or Fluctuation): Met criterion B2ab(iii) and likely 2c(iv) for Threatened. The AO is small (<2000 km²), the species is known from <5 fragmented sites and its prairie habitat is declining. Extreme fluctuations in the number of mature individuals are likely.

Criterion C (Small Total Population Size and Decline): Insufficient information

Criterion D (Very Small Population or Restricted Distribution): Insufficient information

Criterion E (Quantitative Analysis): Insufficient information

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