Species at Risk

Banff Springs Snail

Physella johnsoni

Why is the Banff springs snail in danger?


A colony of snails clinging to dead leaves on a mat of purple bacteria.
By bathing or dipping their hands in the water, people may unintentionally disturb or kill snails as well as their eggs.
© Parks Canada / M. & L Degner / 2002

The world's entire population of Banff springs snails is confined to tiny patches of rare, unique and fragile habitat. In fact, the snail's entire habitat amounts to an area the size of an average Canadian house-170 m2 - all of it within Banff National Park.

The Banff springs snail could easily become extinct unless we protect its habitat. It has already disappeared from some of its historic range. The population seesaws dramatically, with the numbers at their lowest from March to June. This makes the snail especially vulnerable at the beginning of the main tourist season, when human activities pose the greatest threat.

Any factor that affects the thermal spring ecology could harm this species. By bathing or dipping their hands in the water, people may unintentionally disturb or kill snails as well as their eggs. Even minor movements in the water can upset the floating microbial mats on which the snails feed and lay their eggs. Chemicals such as insect repellants and deodorants on people's skin can also harm the snails and their habitat, as can changes in water levels.

Natural threats to the snail may include competition from soldier fly larvae and predation by waterfowl, thrushes, garter snakes and robins, as well as the drying up of thermal springs resulting from global climate change and drought.