Status of the northern leopard frog (Rana pipiens) in Alberta

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The northern leopard frog (Rana pipiens [Lithobates pipiens]) has been designated a “Red List” species in Alberta since 1991. In January 1997 it was afforded legal designation and protection as an “endangered” species under the provincial Wildlife Act. The species was formerly widely distributed and locally abundant in the prairies, foothills, and central parkland in the southern half of the province, but abrupt and dramatic population declines were noted in the late 1970s and early 1980s. Populations have remained at a low level since that time. The species now appears to be extirpated over most of central Alberta and, with the exception of one repatriated population, is apparently now absent from the entire North Saskatchewan River drainage. In southern Alberta, populations are absent or greatly reduced. Since 1981, the northern leopard frog has been reported from 84 locations in the province, although evidence of breeding has only been reported from 27 sites, and only seven sites in southeastern Alberta are considered to support major breeding populations. The vast majority of these records have occurred since 1990. Monitoring data suggest that at least three of the major breeding populations are stable and reproducing successfully on an annual basis. The cause(s) of population declines in Alberta is (are) unknown. Although little studied, the decline in Alberta does not appear to be part of a regular cycle. Instead, it appears to be related to a singular, widespread factor affecting the survivorship of the species. The abrupt declines observed in Alberta appear to follow a similar pattern of sudden and massive declines witnessed in the upper Midwestern states and prairie provinces during the 1970s. Small population recoveries have been noted recently in Saskatchewan and Manitoba, providing promise that recoveries may also occur in Alberta. Re-establishment of populations in formerly occupied areas with suitable habitat may occur as a result of dispersal from the remaining populations in southern Alberta. However, our understanding of dispersal in the northern leopard frog is limited, and it is difficult to predict the extent to which recolonization will occur. In some instances, frogs may have to be transplanted from existing populations in order to establish populations elsewhere. This may be particularly true for central Alberta, which is separated from the remaining populations in southern Alberta by vast stretches of arid land.

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ELECTRONIC FILE - Zoology: Herps

Recommended citation ("may be cited as"): Wagner, G. 1997. Status of the Northern Leopard Frog (Rana pipiens) in Alberta. Alberta Environmental Protection, Wildlife Management Division, Wildlife Status Report No. 9. Edmonton, AB. 46 pp.

SWAP (2/19/2016) citation:
Wagner G. 1997. Status of the northern leopard frog (Rana pipiens) in Alberta. Edmonton (AB): Alberta Environmental Protection, Wildlife Management Division. 46 p. Wildlife Status Report 9. [accessed 2015 Jun 01]. http://esrd.alberta.ca/fish-wildlife/species-at-risk/species-at-risk-pub...