TEXT VERSION - "The day of the salamander."
The summer of the salamander. How the little amphibian forced a big highway project in southwestern Manitoba to work around it, or face legal consequences.
by Larry Powell.
Just as a multi-million dollar road improvement project was about to begin - between Shoal Lake and Hamiota in July - salamanders were found in the wetlands along the right-of-way.
And not just any salamanders. These were the prairie population of tiger salamanders (Ambystoma tigrinum), considered a “species of concern” under the Federal Species at Risk Act.
|Tiger salamanders in captivity. A Wikipedia photo.|
|"Turbidity curtains." A PinP photo.|
As a result, so-called “turbidity curtains” (above) were strung along the area affected. They prevent sediment created in this “hot zone” of construction, from spreading throughout the entire slough. That meant, salamanders trapped within the curtains, had to be caught and moved.
|Luke Roffey. AAE Tech Services. A PinP photo.|
Luke Roffey (above), a biology student at the University of Winnipeg, works for a company hired by the main highway contractor to make sure provisions of the Act are upheld.
He tells PinP the salvage operation is going well, with more than 11 hundred salamanders trapped and relocated. At this writing, that operation was continuing.
Minnow traps baited with “glow-sticks” proved an effective method of capture. But that took longer than expected, delaying the construction project somewhat, but, says Roffey, “not by much.”
|Minnow trap with glow-stick. Photo by Luke Roffey.|
He says he got the distinct impression that construction crews would not have “made way” for the salamanders if the federal legislation had not required them to do so. And, he believes, “Many of the 11 hundred would not have survived,” proving the value of the law.
Salamanders are considered a key part of nature’s food web. Before they emerge from the water, they eat lots of harmful larvae like mosquitoes. And, after they move to their “on-land” (terrestrial) stage, they, themselves become important food for cranes, foxes, pelicans and many other animals.
The Committee on the Status of Endangered Wildlife in Canada, a government advisory body, says the pressures placed on the habitats of this prairie population by farming, oil development and other human activity, are “immense.”
So the salamander larvae eat aquatic invertebrates, such as mosquito larvae, midge larvae, small crustaceans, beetles, and worms. They will also eat the tadpoles of frogs and toads if they occur in the same wetland. And large larvae will even cannibalize smaller ones in overcrowded ponds. When the water is drying up fast, cannibalism helps the larger larvae grow fast enough to be able to become terrestrial before their pond evaporates completely.
Adults eat mainly beetles, crickets, and earthworms. But any creature small enough to fit in their mouth is potentially on the menu.
The aquatic larvae are eaten by garter snakes, herons, cormorants, pelicans, cranes, and mink. On land they are eaten by all these same predators but also badgers, skunks, foxes and owls.
They don't tend to breed in ponds with fish because pike, bass and perch are such effective predators of the larvae.