AN INTRODUCTION TO THE AMPHIBIANS
OF BRITISH COLUMBIA
Columbia Spotted Frog (Rana luteiventris), photo by Werner Eigelsreiter.
Visit the Amphibian Atlas Pages
The word "amphibian" means "double life," and
refers to the tendency of most amphibians (frogs, toads, and salamanders) to have an aquatic, gill-bearing
larval stage (i.e. tadpole stage for frogs) and an air-breathing adult stage that
may live partially or almost entirely on land.
There are three
extant (living) orders or main groups of amphibians in the world:
- the relatively poorly-known
aquatic or soil-dwelling caecilians--legless, tailless, tropical amphibians--(Order Gymnophonia),
- the more
familiar frogs and toads (Order Anura-- meaning tailless),
- salamanders and newts (Order Caudata--meaning tailed).
Amphibians are vertebrate animals, possessing
a backbone and other elements of an internal bony skeleton. They
are ectothermic, or "cold-blooded," meaning that their
internal body temperature is dependent on the temperature of their
surroundings. The skin of most amphibians is delicate, and can
absorb water. Most amphibians respire partially through their skin. Because of this, water-borne pollutants and pathogens
can cause serious damage to amphibian populations.
are declining in numbers. Experts believe the factors responsible include:
- introduction of foreign species (animal and plant)
to amphibian habitats,
- over-collection and other exploitation,
- climate change, including increased levels of UVB insolation and
local effects of global warming,
- spread of fungal and viral pathogens,
- the synergistic interplay of all of these factors.
Red-legged Frog (Rana aurora), photo by Brian Klinkenberg
Amphibians in British Columbia
There are thirteen species of frogs and toads (anurans) and nine species of salamanders in British
Columbia. Many of our BC species are southern species that are more common in the United States. For these species, our BC populations are peripheral, occurring at the northern edge of their range. Others, however, are
widely distributed within B.C. and are not peripheral species.
Most species are found at low elevations
in and near wetlands or riparian habitats. However, there are species
of both frogs and salamanders in BC that are adapted to life in fast-flowing
mountain streams. There is also one desert-adapted frog, the Great
Basin Spadefoot, which occurs in dry southern interior areas, particularly
within the Thompson, Okanagan and Similkameen Valleys.
Some British Columbia species of amphibians do not have the typical aquatic-terrestrial
life history. The Western
Red-backed salamander, Cour d'Alene Salamander, Wandering Salamander,
and Ensatina lay eggs in damp places on land, and lack an aquatic
larval stage. Coastal Giant Salamanders, Northwestern Salamanders, and Tiger Salamanders have neotenic life stages,
which retain gills and remain aquatic throughout their life after reaching sexual maturity.
Coastal Giant Salmander (Dicamptodon tenebrosus), photo by Hugh Griffith
It is partly because many amphibian species require both
particular aquatic and terrestrial habitats that amphibians throughout
the world are in decline, since loss or degradation of either habitat
can eradicate a population. Aquatic stages are particularly vulnerable
to environmental changes. Any slight alteration of water temperature,
turbidity, dissolved oxygen levels, other characteristics of water
chemistry, predatory regime, or physical complexity of habitat,
can be harmful. Because embryos develop in eggs that are laid in
shallow water, it is also possible that increased ultraviolet radiation,
caused by depletion of the earth's ozone layer, plays a role in
mortality (Blaustein et al., 1998; Trenham and Diamond, accessed 2005). Most amphibians have moist, sensitive
skin, which is involved in both drinking and dermal respiration.
Industrial pollution and pesticide run-off are thus threats at
any life stage. Recently, amphibian populations worldwide have
been found to be infected with chytridiomycete fungi (Weldon et al., 2004), which causes dermal damage and
mortality in terrestrial forms. Another fungus (Saprolegnia
ferax), introduced into bodies of water during fish stocking,
has been linked to the death of amphibian eggs (Kiesecker et al., 2001).
In British Columbia, habitat destruction and range fragmentation
are endangering a number of species. Draining of wetlands, and
flood-control measures in expanding urban and agricultural areas,
remove vast areas of habitat, and break historical distributions
into disconnected fragments. Clearing of forests, and secondary
effects from logging practices, impact both larval and adult stages.
Several species have very restricted, relictual ranges which make
them highly vulnerable to aquatic habitat degradation or the introduction
of predatory game or baitfish into breeding lakes.
The amphibians of British Columbia are listed
in the following tables, with links to discussions of species that
are threatened or endangered in the province.
Western Red-backed Salamander (Plethodon vehiculum), colour morphs.
Photo by Hugh Griffith.
Visit the Amphibian Atlas Pages
Table 1: Ecoprovince Occurences of BC Frogs and Toads
Rocky Mountain Tailed Frog
||Southern Interior Mountains
Coastal Tailed Frog
||Northern Boreal Mountains, Coast and Mountains, Georgia Depression
||Coast and Mountains, Georgia Depression, Central Interior, Southern Interior, Southern Interior Mountains
|Boreal Chorus Frog
|| Northern Boreal Mountains
| Red-legged Frog
||Georgia Depression, Coast and Mountains
|Columbian Spotted Frog
||Northern Boreal Mountains, Sub-boreal Interior, Central Interior, Southern Interior, Southern Interior Mountains
| Northern Leopard Frog
| Oregon Spotted Frog
||Northern Boreal Mountains, Taiga Plains, Boreal Plains, Central Interior, Southern Interior, Southern Interior Mountains
||Northern Boreal Mountains, Coast and Mountains, Georgia Depression, Taiga Plains, Boreal Plains, Central Interior, Southern Interior, Southern Interior Mountains
| Great Basin Spadefoot Toad
Ensatina (Ensatina eschscholtzii). Photo by Hugh Griffith.
Table 2: Ecoprovince Occurrences of BC Salamanders
||Coast and Mountains, Georgia Depression
|Western Long-toed Salamander
||Coast and Mountains, Georgia Depression, Sub-boreal
Interior, Central Interior, Southern Interior, Southern Interior
| Tiger Salamander
| Coastal Giant Salamander (formerly known as the Pacific Giant Salamander)
| Wandering Salamander
||Coast and Mountains (s. Vancouver Island)
Coeur d'Alene Salamander
||Southern Interior, Southern Interior Mountains
|Western Redback Salamander
||Coast and Mountains, Georgia Depression, Southern
||Coast and Mountains, Georgia Depression
||Coast and Mountains, Georgia Depression
Blaustein, A. R., J. M. Kiesecker, D. P. Chivers, D. G. Hokit, A. Marco, L.K. Beldon, and A. Hatch. 1998. Effects of ultraviolet radiation on amphibians: field experiments. American Zoologist 38: 799-812.
Kiesecker, J. M., A. R. Blaustein and C. L. Miller. 2001. Transfer of a pathogen from fish to amphibians. Conservation Biology 15: 1064-1070.
Trenham, P.C. and S.A. Diamond. 2005. UV and Amphibians in Wetlands. Coordinated studies of ultraviolet radiation and lentic breeding amphibians. Accessed December 2005.
Weldon C, du Preez L. H., Hyatt A. D., Muller R., Speare R. Origin of the amphibian chytrid fungus. Emerging Infectious Diseases [serial on the Internet]. 2004 Dec [cited 2005 Dec]. Available: http://www.cdc.gov/ncidod/EID/vol10no12/03-0804.htm
Adama, D. B., K. Lansley, and M. A. Beaucher.
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rearing and reintroduction in Southeast British Columbia, 2003.
Report to the Columbia Basin Fish and Wildlife Compensation Program.
Nelson, BC. 26 pp.
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Basin Ecosystems from 1827 to 1990. Environmental Management 21:
B.C. Conservation Data Centre. 2005. Conservation
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Resource Management. Available: http://srmapps.gov.bc.ca/apps/eswp/
Collins, J. T. and T. W. Taggart. 2002. Standard
Common and Current Scientific Names for North American Amphibians,
Turtles, Reptiles and Crocodilians. 5th Edition. Center for North
American Herpetology, Lawrence Kansas. iv + 44 pp.
Corkran, C. and C. Thoms. 2006. Amphibians of Oregon, Washington and British Columbia. A Field Identification Guide. Lone Pine. Vancouver. 176 pp.
Green, D. M. and W. Campbell. 1984. Amphibians
of British Columbia. Royal British Columbia Museum Handbook. Victoria, BC.
Green, D. M., H. Kaiser, T. F. Sharbel, J. Kearsley
and K. R. McAllister. 1997. Cryptic species of spotted frogs, Rana pretiosa complex,
in western North America. Copeia 1997: 1-8.
Haycock, R. D. 2000. COSEWIC status report on
the Oregon spotted frog Rana pretiosa in Canada. Committee
on the Status of Endangered Wildlife in Canada. Ottawa, Ontario.
Jackman, T. R. 1998. Molecular and historical
evidence for the introduction of clouded salamanders (genus Aneides) to
Vancouver Island, British Columbia, Canada, from California. Canadian
Journal of Zoology 76: 1570-1580.
Johnston, B. Coastal Giant Salamander. 2004.
Accounts for Managing Identified Wildlife. BC Ministry of Environment, Lands and Air Protection, Vancouver, BC.
Johnston, B. and L. Frid. 2002. Clearcut logging
restricts the movements of terrestrial Pacific giant salamanders
(Dicamptodon tenebrosus Good). Canadian Journal of Zoology 80: 2170-2177.
Mallory, A. 2004. Coastal Tailed Frog Ascaphus
truei. Accounts and Measures for Managing Identified Wildlife. B.C. Ministry of Water, Land and Air Protection, Vancouver BC.
Matsuda, B. M., D. M. Green and P. T Gregory. 2006. Amphibians and Reptiles of British Columbia. Royal BC Museum Handbook. Victoria. 266 pp.
Maxcy, K. A. 2004. Red-legged Frog. Accounts
and Measures for Managing Identified Wildlife. B.C. Ministry of
Water, Land and Air Protection. Vancouver BC. Accounts V. 2004.
12 pp. PDF
Natureserve Explorer, 2005. www.natureserve.org.
Northern Prairie Wildlife Research Center. 1997.
Checklist of Amphibian Species and Identification Guide. An Online
Guide for the Identification of Amphibians in North America north
of Mexico. North American Reporting Center for Amphibian Malformations.
Jamestown, ND: Northern Prairie Wildlife Research Center Home Page.
http://www.npwrc.usgs.gov/narcam/idguide/ (Version 30 Sept., 2002).
Ovaska, K. and L. Sopuck. 2004. Update COSEWIC
Status report on the Red-legged Frog, Rana aurora, in
Canada. Report prepared for the Committee on the Status of Endangered
Wildlife in Canada. Ottawa, Ontario. 46 pp.
Reimchen, T. E. 1990. Introduction and dispersal
of the Pacific treefrog, HYLA REGILLA, on the Queen Charlotte Islands,
British Columbia. Canadian Field Naturalist 105:288-290.
Richardson, J. S. and W. E. Neill. 1998. Headwater
amphibians and forestry in British Columbia: Pacific Giant Salamanders
and Tailed frogs. Northwest Science 72: 122-123.
Ritland, K., L. A. Dupuis, F. L. Bunnell, W. L. Y.
Hung and J.E. Carlson. 2000. Phylogeography of the tailed frog
(Ascaphus truei) in British Columbia. Canadian Journal
of Zoology 78: 1749-1758.
Schock, D. M. 2001. COSEWIC Status Report on
the Tiger Salamander, Ambystoma tigrinum, in Canada. Committee
on the Status of Endangered Wildlife in Canada. 43 pp.
Seburn, C.N.L. and D. Seburn. 2000. Status Report:
northern leopard frog (Rana pipiens) (Western population).
Committee on the Status of Endangered Wildlife in Canada. 43 pp.
Waye, H. 1999. Status report on the Northern
red-legged frog, Rana aurora, in Canada. Report prepared for the
Committee in the Status of Endangered Wildlife in Canada. Ottawa.
Wind, E. and L. A. Dupuis. 2002. COSEWIC status
report on the western toad Bufo boreas in Canada. Committee
on the Status of Endangered Wildlife in Canada. Ottawa. 31 pp
Pacific Tree-Frog, photo by David Blevins
The Centre for North American Herpetology
accounts of amphibian species worldwide, including causes for declines
and conservation status rankings.
Diseases Home Page
to the Amphibia - from UC Berkeley, including Fossil History,
Life History and Ecology, Syetematics and Ecology.