Western toad (Bufo boreas) COSEWIC assessment and status report: chapter 12

Technical Summary

Bufo boreas

Western Toad – Crapaud de l’Ouest

Range of Occurrence in Canada:

YT NT BC AB Parks YFWMB

Extent and Area information

extent of occurrence (EO) (km²)

Based on map Fig. 3 in report: Ca. 1,300,000 km²

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

Stable

are there extreme fluctuations in EO?

No

area of occupancy (AO) (km²):

Ca. 130,000 km²

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

Decline especially on Vancouver Island and adjacent mainland

are there extreme fluctuations in AO ?

No

number of extant locations:

A great many

specify trend in #:

Decline especially on Vancouver Island and adjacent mainland

are there extreme fluctuations in # locations?

No

habitat trend:

Declining quality & extent especially on Vancouver Island and adjacent mainland

Population information

generation time:

3 – 4 yrs

number of mature individuals:

unknown

total population trend:

Decline especially on Vancouver Island and adjacent mainland

% decline over the last/next 10 years or 3 generations.

unknown

extreme fluctuations in number of mature individuals?

Most probably

is the total population severely fragmented?

yes

list populations with number of mature individuals in each:

unknown

specify trend in number of populations: Decline especially on Vancouver Island and adjacent mainland

are there extreme fluctuations in number of populations?

no

Threats (actual or imminent threats to populations or habitats)

  • agricultural and urban development
  • road traffic
  • habitat deterioration, including fragmentation and the creation of unsuitable but attractive breeding ponds
  • introduced exotic predators and competitors, especially bullfrogs and predatory fish
  • diseases (Saprolegnia, chytridiomycosis)
  • unknown factors implicated in US declines
  • agricultural and urban development
  • road traffic
  • habitat deterioration, including fragmentation and the creation of unsuitable but attractive breeding ponds
  • introduced exotic predators and competitors, especially bullfrogs and predatory fish
  • diseases (Saprolegnia, chytridiomycosis)
  • unknown factors implicated in US declines

Rescue Effect (immigration from an outside source)?

negligible

does species exist elsewhere (in Canada or outside)?

yes

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