BC Conservation Data Centre: Conservation Status Report
Ambystoma mavortium
Western Tiger Salamander
| Scientific Name: | Ambystoma mavortium |
|---|---|
| Scientific Name Synonyms: |
Ambystoma tigrinum
|
| English Name: | Western Tiger Salamander |
| English Name Synonyms: |
Barred Tiger Salamander
Blotched Tiger Salamander Tiger Salamander |
| Provincial Status Summary | |
| Status: | S2 |
| Date Status Assigned: | June 01, 1996 |
| Date Last Reviewed: | December 21, 2021 |
| Reasons: | This species' restricted distribution and its vulnerability to introductions of fish, drainage of wetlands and rapid and extensive loss of terrestrial habitats put it at risk. |
| Range | |
| Range Extent: | D = 1,000-5,000 square km |
| Range Extent Estimate (km2): | 3944 |
| Range Extent Comments: | This salamander occurs in the dry southern interior region of the province, south of Peachland. It is restricted to scattered, isolated populations in the South Okanagan, Lower Similkameen, and Kettle River watersheds with the range extending south to the U.S. border (COSEWIC 2012g). The range estimate (convex hull) was calculated to be 3944 km2, based on CDC mapped occurrences, current to 2018. |
| Area of Occupancy (km2): | E = 26-125 |
| Area of Occupancy Estimate (km2): | 368 |
| Area of Occupancy Comments: | The area of occupancy was calculated to be 368 km2 (92 2km x 2km grid cells) based on CDC mapped occurrences, current to 2018. |
| Occurrences & Population | |
| Number of Occurrences: | C = 21 - 80 |
| Comments: | This salamander is restricted to the Okanagan - Similkameen, midway and Grand Forks. The BC Conservation Data Centre has 57 mapped occurrences (based on NatureServe mapping specifications) which are current to 2018. |
| Number of Occurrences with Good Viability / Ecological Integrity: | BC = 1 - 12 |
| Comments: | A few occurences are ranked as having good viability (BC CDC 2006). Although population viability analysis has not been conducted on any local populations, there are virtually no populations that are not impacted by predatory fish, traffic mortality, or water levels that are so low that extended periods of drought prevent reproduction. |
| Number of Occurrences Appropriately Protected & Managed: | Rank Factor not assessed |
| Comments: | In British Columbia, 14 breeding sites (16.2% of 86 known sites) are within protected areas in parks (9 sites) or in Wildlife Habitat Areas on Crown land (5 sites). An additional 23 sites (26.7%) receive or are expected to receive some form of protection through voluntary stewardship agreements (COSEWIC 2012g). |
| Population Size: | E = 2,500 - 10,000 individuals |
| Comments: | It is difficult to estimate adult numbers because of the probability of great population fluctuations, and because of their secretive nature, however the estimate likely falls within the parameters of "E"; i.e. 2500 to 10,000. Successful breeding can produce large numbers of offspring but survivorship to breeding age likely is low. |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | AB = Very high - high |
| Comments: | "Threats include direct harm and habitat fragmentation from roads, predation from non-native species (fish, amphibians), diseasecausing organisms, pollution, agricultural activities causing habitat loss and pollution, housing and urban area development, dams and water management, and climate change (drought)." (Southern Interior Reptile and Amphibian Working Group 2016). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | U = Unknown |
| Comments: |
From COSEWIC 2012g: Tiger Salamanders have suffered greater than 50% loss of available breeding habitat, largely through degradation and stocking with predatory fish. Human population growth in the region is also resulting in significant loss of habitat for terrestrial adults. There is an inferred decline in the number and size of populations in the Southern Mountain region in British Columbia. From Sarell (1996): Tiger Salamanders have disappeared from several lakes due to the introduction of fish and numbers have dramatically declined in others. Extended periods of droughts have made many breeding sites unsuitable, impacting reproduction and recruitment. |
| Long-Term Trend: | U = Unknown |
| Comments: | Tiger Salamanders are likely to perisist in isolated areas where the areas are protected and impacts are limited, while the remainder of the range is being fragmented by development and impacts are extensive. |
| Other Factors | |
| Intrinsic Vulnerability: | B=Moderately vulnerable |
| Comments: | Tiger Salamanders are most vulnerable when they move between breeding and terrestrial habitats. During these movements they can encounter traffic, pitfalls and domestic predators. They are also susceptible to predation and many breeding sites from introduced fish and earthmoving activities at their terrestrial sites. Tiger Salamanders may be affected by pesticides which can occur in soils at terrestrial habitats and may be concentrated at some breeding sites. |
| Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
| Comments: | Tiger Salamanders have a reasonably broad tolerance of habitat conditions. The most specific are paedogenic populations that require permanent waterbodies for their entire lives. All known paedogenic populations have been impacted by the introduction of fish to these lakes. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | Continue taxonomic research to determine relationships between this population and others in the A. mavortium - A. tigrinum complex. Studies are needed of habitat needs and seasonal ranges of terrestrial adults. |
| Inventory Needs: | Thorough long-term inventories of immigrating and emigrating adults need to be done at key waterbodies in order to establish population estimates. In other waters, inventories to determine presence are needed to further establish range and estimate total numbers. Further inventories are required to determine the extent of their range, especially in the Thompson, Princeton, and Santa Rosa areas. |
| Stewardship | |
| Protection: | Stewardship agreements are needed where breeding sites occur on private properties. |
| Management: | Permanent, fish-free areas where salamanders occur should be protected and maintained as fish-free. Waterbodies within grazed lands should be at least partially fenced or managed in such a way to avoid extensive cattle use. Underpassess are required to reduce mortality where roads intersect migration routes. |
| Version | |
| Author: | M. Sarell, L. Westereng and L. Gelling |
| Date: | November 16, 2016 |
| References | |
|
BC Conservation Data Centre: Conservation Data Centre Mapping Service [web application]. 2006. Victoria, British Columbia, Canada. Available: http://maps.gov.bc.ca/imf50/imf.jsp?site=cdc.
|
|
|
Geraghty, C., and R. Willey. 1992. Current habitat status of and anthropogenic impacts on the tiger salamander, AMBYSTOMA TIGRINUM NEBULOSUM. Abstract, 6th Annual Meeting of the Society for Conservation Biology, p. 61.
|
|
|
Green, D.M. 1999. British Columbia Amphibians: A taxonomic catalogue. B.C. Minist. Environ., Lands and Parks, Victoria. Wildl. Bull. No. B-87. 22pp.
|
|
|
Green, D.M., and R.W. Campbell. 1984. The Amphibians of British Columbia. Royal B.C. Mus. Handb. No. 45. 101pp.
|
|
|
Irschick, D.J., and H.B. Shaffer. 1997. The polytypic species revisited: morphological differentiation among Tiger Salamanders (Ambystoma tigrinum) (Amphibia: Caudata). Herpet. 53(1):30-49.
|
|
|
Leonard, W., H. Brown, L. Jones, K. McAllister, and R. Storm. 1993. Amphibians of Washington and Oregon. Seattle Audubon Soc., The Trailside Ser., Seattle, WA. 168pp.
|
|
|
Matsuda, B.M., D.M. Green and P.T. Gregory. 2006. Royal BC Museum handbook amphibians and reptiles of British Columbia. Royal B.C. Mus., Victoria, BC. 266pp.
|
|
|
Sarell, M.J. 1995. Status of the tiger salamander (Ambystoma tigrinum) in British Columbia. Unpubl. rep. submitted to B.C. Environ., Wildl. Branch, Victoria. 18pp.
|
|
|
Sarell, M.J. 1996. Status of the Tiger Salamander (Ambystoma tigrinum) in British Columbia. Prepared for B.C. Minist. Environ., Lands and Parks, Victoria. 18pp.
|
|
|
Southern Interior Reptile and Amphibian Working Group. 2016. Recovery plan for the Blotched Tiger Salamander (Ambystoma mavortium) in British Columbia. Prepared for the B.C. Ministry of Environment, Victoria, BC. 39 pp.
|
|
Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2016. Conservation Status Report: Ambystoma mavortium. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Oct 7, 2025).