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COSEWIC Assessment and Status Report on the White Flower Moth (Schinia bimatris) in Canada

Technical Summary

Schinia bimatris

White Flower Moth – Héliotin blanc satiné

Range of Occurrence in Canada: Southwestern Manitoba

Extent and Area information

extent of occurrence (EO) (km²): Max 250 km²
specify trend (decline, stable, increasing, unknown) : unknown
are there extreme fluctuations in EO (> 1 order of magnitude)?unknown
area of occupancy (AO) (km²): 5 km²
specify trend (decline, stable, increasing, unknown) : Has undergone serious declines until recent past, possibly stabilized or even increasing slowly due to sand dune re-activation as a result of drought, but (a) this may only be a fluctuation, and (b) hotter, drier conditions may be unsuitable.
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 : Unknown.  Dune re-activation may be occurring due to climate change, but the hotter, drier conditions may not be suitable for the moth.

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):100 – 5,000
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):unknown
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)? probably
list each population and the number of mature individuals in each: Spirit Dunes: 100 – 5,000
specify trend in number of populations (decline, stable, increasing, unknown) : stable, as far as is known
are there extreme fluctuations in number of populations (>1 order of magnitude)? unlikely

Threats (actual or imminent threats to populations or habitats)

The habitat requirements are not known for Canadian populations, but habitat loss through dune stabilization and changing dune microhabitat may be threats.

Rescue Effect (immigration from an outside source)extremely low
does species exist elsewhere (in Canada or outside)? yes
status of the outside population(s)? unknown
is immigration known or possible? highly unlikely (nearest known pop in Nebraska ~1000 km away)
would immigrants be adapted to survive here? unknown
is there sufficient habitat for immigrants here? unknown

Quantitative Analysis

Current Status

COSEWIC:Endangered (May 2005)

Status and Reasons for Designation

Status:  Endangered

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

Reasons for Designation: This moth is associated with dune habitats and is known from a small number of scattered sites in North America, with only one extant site in Canada. Most dune habitats in Canada appear to be too dry for this species. Dune habitat has undergone serious declines and the moth has likely declined as well.

Applicability of Criteria

Criterion A (Declining Total Population): Insufficient data.

Criterion B (Small Distribution, and Decline or Fluctuation): Meets B1ab(iii)c(iv)+2 ab(iii)+(c)(iv) for endangered.  The extent of occurrence is much less than 5,000 km², the area of occupancy is much less than 500 km², with a population that is very likely severely fragmented and occurring at only one known location (reasonable confidence that it occurs at one, maybe two locations) with serious declines in suitable habitat and probable extreme fluctuations in the number of mature individuals, based on existence of such fluctuations in more southern populations of the species.

Criterion C (Small Total Population Size and Decline):  Not applicable.

Criterion D (Very Small Population or Restricted Distribution): Meets D2 for threatened.  It occupies and area of less than 20 km²and is known to occur at less than 5 locations.

Criterion E (Quantitative Analysis): Insufficient data.