Spotted bat (Euderma maculatum) COSEWIC assessment and status report: chapter 12
Technical Summary
Euderma maculatum
Spotted Bat – Oreillard maculé
Extent and Area information
Population information
(> 1 order of magnitude)?
found within small and relatively isolated (geographically or
otherwise) populations between which there is little exchange,
i.e., < 1 successful migrant / year)?
increasing, unknown)
(>1 order of magnitude)?
Threats (actual or imminent threats to populations or habitats)
- disturbance to cliff roosting sites
- loss of riparian foraging habitat
- impact of pesticides on the moth prey base
status of the outside population(s)?
- Rare
- Idaho S2
- Montana S1
- Washington S3
Quantitative Analysis
- *80 occurrences;
- 40 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: S3S4
Status and Reasons for Designation
Status: Special Concern
Alpha-numeric code: [The estimated Canadian population (<1000 adults) met criterion for Threatened D1, but it was designated Special Concern because there is a possibility of rescue effect from neighbouring populations in the United States. Foraging and roosting habitats appear to be secure in Canada.]
Reasons for Designation: In Canada, this species occurs in the intermontane grasslands of southern British Columbia. It is a distinctively coloured bat that is unmistakable to identify. Unlike any other Canadian species of bat, it has echolocation calls that are within the range of human hearing. It roosts in crevices in large cliff faces. It is considered the most easily and best censused species of bat in Canada. Population estimates, based on relatively good census effort, suggest that there are fewer than 1000 adults. At this time, numbers appear to be stable, and there are relatively few threats to populations or habitats. Perhaps the biggest threat to this species is its small population size. Use of pesticides on its prey, loss of foraging habitat, and disturbance at roosting sites by rock climbers are potential threats. Rescue may be possible from neighbouring populations in the United States; however, movements of individuals between Canadian and US populations are not documented.
Applicability of Criteria
Criterion A (Declining Total Population): < 1000 adults in Canada.
Criterion B (Small Distribution, and Decline or Fluctuation): 10600 km² in Canada.
Criterion C (Small Total Population Size and Decline): No evidence of population decline.
Criterion D (Very Small Population or Restricted Distribution): Meets the criterion for Threatened under D1. < 1000 adults in Canada.
Criterion E (Quantitative Analysis): Probability of extinction in Canada, unknown.
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