Fringed bat COSEWIC assessment and status report: chapter 12

Technical Summary

Myotis thysanodes

Fringed Bat – Chauve-souris à queue frangée

Range of Occurrence in Canada:

British Columbia

Extent and Area information

extent of occurrence (EO) (km²) :

8,650 km²

specify trend (decline, stable, increasing, unknown) :

Unknown

are there extreme fluctuations in EO (> 1 order of magnitude)?

Unknown

area of occupancy (AO) (km²) :

Unknown

specify trend (decline, stable, increasing, unknown)

-

are there extreme fluctuations in AO (> 1 order magnitude)?

-

number of extant locations :

33*

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

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.) :

2

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)

-

are there extreme fluctuations in number of mature individuals (> 1 order of magnitude)?

-

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)?

No

list each population and the number of mature individuals in each

-

specify trend in number of populations (decline, stable, increasing, unknown)

-

are there extreme fluctuations in number of populations (>1 order of magnitude)?

-

Threats

  • disturbance of maternity colonies and night roosts
  • loss of riparian habitat
  • impacts of pesticides on invertebrate prey

Rescue Effect (immigration from an outside source)

Moderate

does species exist elsewhere (in Canada or outside)? Yes

status of the outside population(s)?

  • Uncommon
  • Idaho S1?
  • Montana S3
  • Washington S3?

is immigration known or possible?

Yes

would immigrants be adapted to survive here?

Yes

is there sufficient habitat for immigrants here?

Yes

Quantitative Analysis

* 33 occurrences; 18 element occurrences. An element occurrence for small bats is defined by the Heritage Ranking System as sites occupied historically or at present that are separated by 10 km or more. 

Other Status

COSEWIC: Special Concern 1988

British Columbia: S2S3

Status and Reasons for Designation

Status: Data Deficient

Reasons for Designation: This species is rarely reported in its Canadian range. There are, however, a few sites in the Okanagan Valley where they regularly can be captured during the summer. There is a lack of data about the extent of its Canadian range and the habitat that is important for foraging and roosting. We also do not know the population size or trends, nor any key demographic characteristics, such as population structure, reproduction or survival rates. It is not known if this species overwinters in Canada or migrates south for the winter; however, there are maternity colonies recorded in Canada.

Applicability of Criteria

  • Criterion A (Declining Total Population): Population sizes unknown. 
  • Criterion B (Small Distribution, and Decline or Fluctuation): Extent of distribution unknown. 
  • Criterion C (Small Total Population Size and Decline): No evidence of population decline. 
  • Criterion D (Very Small Population or Restricted Distribution): Unknown. 
  • Criterion E (Quantitative Analysis): Probability of extinction in Canada, unknown.

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