August 12, 2008

Study Aims To Protect Rattlesnakes From Canadian Roads

A Canadian graduate student is exploring why rattlesnakes in southeastern Alberta slither onto, and often die, on the asphalt blacktop of the regions roads.

Adam Martinson, a University of Calgary student working on a Masters degree, has come to Dinosaur Provincial Park, listed as a United Nations World Heritage site, to further study this odd phenomenon.

"Road mortality is a significant factor of influencing snake populations around the world," Martinson said. "In southern Alberta it's particularly important because the snakes aren't moving very fast across the roads and there is a huge amount of development."

He said snakes are pressured by both oil and gas exploration in the Western Canadian province's semi-desert southeast, but also by residential development in the booming region.

Roads are often a deadly hazard for prairie rattlesnakes, considered to be potentially a "species at risk" by the Alberta government, and bull snakes, their nonvenomous cousins.

These snakes tend to slither onto roads looking for safety, food, mates and the heat absorbed by the asphalt. However, when a vehicle approaches the snakes don't move.

They coil themselves up in a defensive posture and the rattlers shake their tails to warn off the danger.

This strategy, which has served them well for millions of years, is not match, however, for an oncoming motor vehicle.

Martinson said snakes are run over almost every day.

More than 80 percent of timber rattlesnakes that tried to cross roads traveled by 2,000 or more vehicles a day were killed, according to one South Carolina study.

Martinson said the research is an attempt to learn "how we can design roads and plan for roadways that are going to have less of an impact on snakes."

For the study, Martinson is first trying to get a firmer handle on just how many bull and rattlesnakes there are in southern Alberta. Both species are considered "data deficient" by wildlife conservation agencies, meaning that no one really knows how many of the reptiles live in the region.

The snakes are a key to the area's ecosystem, keeping a check on rodent populations. They are also prey for other creatures.

Martinson traps snakes within the park and releases them onto a control road, where he tracks how fast they move across the surface and at what angle.

The data he collects will be used to create a model to predict the probability of a snake being killed based on traffic density.

But in an area rich in beds of dinosaur fossils, it's clear that industry is a risk for the reptiles.

Part of a daily routine, conservation officers stop their trucks and scoop up the dead serpents and throw them into the vehicle's bed.

It's another statistic for Martinson's study.


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