Snake Research in Dinosaur Provincial Park
Updated: June 9, 2010
Recent studies estimate that one million vertebrates are killed on roads every day in the United States. In Australia up to five million reptiles and amphibians are killed on roads each year. Here in Alberta most reptile species are at or near the edge of their range and road mortality is a potentially serious issue for their conservation. For prairie rattlesnakes and bullsnakes, which are commonly found dead on prairie roads in southern Alberta, we don’t fully understand the impacts of road mortality on populations. However, there is strong evidence that the effects are significant.
To address the lack of sound information on prairie rattlesnakes and bullsnakes in Alberta, ongoing monitoring of both species is occurring at Dinosaur Provincial Park. Currently, over 200 prairie rattlesnakes and over 100 bullsnakes have been fitted with microchip implants known as ‘passive integrated transponders’ (or PIT tags) for identification if recaptured. Through this type of long-term study important factors such as population levels, reproduction success and mortality rates can help determine trends for both species in the province.
Another component of this research examined snake behavior when encountering roads, and used this information to predict the probability of individuals being killed when crossing. The results were shocking: on a road that averages only 353 vehicles per-day prairie rattlesnakes had an 18% chance of being hit by a vehicle when attempting to cross. When this unnatural source of mortality is consider in addition to natural (and other human-induced) causes of death, there may well be consequences for the long-term conservation of the population as a whole.
By analyzing the number of prairie rattlesnakes and bullsnakes captured in specially designed traps throughout Dinosaur Provincial Park, movement patterns could be compared to local weather. Understanding how weather influences snake behaviour is important because this information can be used to predict when snakes are most likely to encounter and cross roads.
With this knowledge Park planners and managers can develop strategies to ensure that snakes get safely to the other side.
By installing crossing structures such as tunnels, culverts, or cattle-guards, and by limiting speed on high-risk roads, or at high-risk times, Alberta Parks can reduce the impacts of vehicle mortality on established roads. Where new roads or recreational infrastructure is being planned, snake mortality can be reduced by including effective buffer zones around hibernacula (dens), and by limiting development to low-risk areas.
Unfortunately, road signs to raise driver awareness have proven to be ineffective in other areas. Sadly, when some people are more aware of snakes on the road, they are more likely to deliberately drive over them! Clearly, for any protection strategy to succeed, it is important that people be informed on the topic, which hopefully will increase both their concern for snakes and other wildlife, and their support of effective conservation measures.
Adam Martinson (M.E.Des.) collected field information at Dinosaur Provincial Park for his masters degree in environmental science with the Faculty of Environmental Design at the University of Calgary.
You can find more information on the status prairie rattlesnake and conservation efforts in Alberta at these sites:
- Adam Martinson’s site: www.iBrakeForRattleSnakes.com