Although the climate and conditions are harsh in the Canadian Rockies, a handful of amphibian species somehow manage to survive in the mountain national parks.
Parks Canada recently announced they had stumbled across two previously unknown high-elevation locations that are home to boreal toads in Banff National Park.
The discovery was made during work on an ecological restoration project at Devon Lakes, a chain of four lakes that form the source of the Clearwater River, about 80 kilometres north of the Banff townsite.
Charlie Pacas, an aquatics expert for Banff National Park, said they found toads and tadpoles in a cool spring tributary entering the Clearwater River.
“We found adult toads in the area every year, and in the marginally warmer water found above the coldwater spring, we always found tadpoles well into late September and October,” said Pacas.
“We always wondered what would happen to those tadpoles as fall and winter progressed.”
The second location in this harsh environment was a relatively large, yet shallow wetland pond.
Pacas said that on some occasions, researchers would find literally tens of thousands of boreal toad tadpoles along the shoreline margins of the pond.
“On one memorable visit in 2009, we also saw large black masses of emergent tadpoles which numbered well into the many thousands,” he said.
“It appeared as if thousands of these individuals all piled onto each other and many were also sunning themselves. On our way out of the wetland we also encountered nine adults.”
There are four families of amphibians, represented by three frog species, two toads and two salamander species, in Banff, Kootenay and Yoho Parks, and Rocky Mountain House National Historic Site.
One frog species – the northern leopard frog – has recently disappeared from this region and is now considered locally extinct. It was found in Kootenay National Park.
Toads are terrestrial amphibians. In the mountain national parks, boreal toads are found at all elevations and prefer damp conditions, from meadows to forests.
They are active in spring around lakes, ponds, streams and rivers. They lay their eggs in very shallow water– about four to 15 centimetres deep – in temporary or permanent ponds and lake edges.
Boreal toads have short legs and will walk as well as hop.
The call of an adult toad is a rapid, high-pitched peeping. Large oval poisonous parotid glands are located behind the eyes and their skin is dry and rough, with round, often reddish warts.
The body is green to brown with blotches of brown, grey, green or red, with a light stripe down the back. Underside is pale with dark mottling. Colour is variable between males and females.
Egg laying at a site is synchronized with all females laying eggs within a week, and each female laying as many as 16,500 eggs, which hatch in three to 12 days.
Large numbers of tadpoles will congregate in warm, shallow water before transforming into juvenile toads six to eight weeks after they have hatched.
