Bruce Peninsula Herptile Road Kills
Field Notes (July 2010)
– Rod Steinacher
We’ve all seen them; crushed herptiles (snakes, frogs, salamanders, and turtles) along the roads of the upper Bruce Peninsula. Just last weekend, I removed two dead Eastern Massasauga Rattlesnakes from the Cape Hurd Road, and submitted them for DNA analysis as part of a species at risk program. High vehicle speeds and traffic levels are experienced in the area during the months of June, July, and August, when snakes and frogs are most likely to be found on area roads. Any creatures on the road are at a very real risk, whether they have four legs, two legs, or no legs.
A recent study (Reed & McKenzie, 2010), completed along a 20.3 kilometer stretch of the Dyers Bay and Cabot Head Roads, and covering 65 afternoons between the middle of August and the end of October 2009, found 247 dead snakes of nine species on the roads. The numbers become even more significant when the nearly 400 km of roads on the northern Bruce Peninsula (20 times as much as in the study area) are considered! Road kills were noted anywhere that suitable snake habitat was found adjoining the roads, and were not noticeably focused in any particular “hot spots”.
Between 1983 and 2008, a series of studies of herptile mortality along the 5.5 kilometers of the Cyprus Lake Road were completed for Bruce Peninsula National Park. After correlating the results across these studies, 245 road kills were analyzed. 46% of the deaths, or 114 individuals, were frogs (Bull Frog, Green Frog, Spring Peeper, Gray Treefrog, and Northern Leopard Frog). 105 snakes, representing 43% of all of the road kills, (Brown Snake, Common Garter Snake, Massasauga Rattle Snake, and Milk Snake) were detected. Seven Common Snapping Turtles were killed, along with 15 salamanders and newts (Eastern Red-backed Salamander, Four-toed Salamander, Jefferson Salamander “complex”, and Eastern Newt). A lot of numbers, which basically say that these populations are likely being impacted significantly by the roadway.
Having taken a look at the grim toll, the immediate question is how can these numbers be mitigated, or reduced? In other areas, such as the Netherlands, Manitoba, New York State, and in Killbear Provincial Park in Ontario, a combination of public awareness signage and speed reduction techniques (including speed bumps) have proven very useful in reducing the number of deaths. Closer to home, Bruce Peninsula National Park is proceeding with its own mitigation program, as part of the Cyprus Lake revitalization project. A report (Gunson, 2010) tabled for the park in June, also suggested the use of one or more “eco-passages” under the busy Cyprus Lake Road, in addition to signage and speed reduction measures. A road kill “hot spot” has been identified at about 1 kilometer along the Cyprus Lake Road from Highway #6, and will likely be the site of an eco-passageway. These passageways are essentially culverts, often made of concrete, with low fencing guiding herptiles into the it from as much as 200 meters along the side of the road in either direction. A grate in the top of the passageway provides light and moisture inside to encourage the herptiles to travel through it. The park considers public education as one of its major mandates, and the eco-passageway project should demonstrate the benefits of mitigating road kills to both park visitors and local residents.
On a personal level, what can residents of the Bruce Peninsula do to reduce the number of animals killed on area roads? These animals are rarely the cute, cuddly types and most people feel that they can get along just fine without them. However, it is worth remembering that, whatever our own personal opinion is of “creepy crawlers”, they are an important part of any healthy ecosystem. Simply reducing vehicle speed is one of the main fixes, and awareness of what is on the road during the summer months is also important. While swerving to avoid an animal on the road is not recommended, it is often possible to avoid them without endangering a vehicle and its occupants. It is possible for individuals to do their part in preserving an important part of the Bruce Peninsula’s varied wildlife.
For further reading and action on the subject of road kills in herptiles, and other animals, see:
1. Dyer’s Bay Snake Road Kill Study
– Glenn Reed & Theresa McKenzie (March 2010)
2. “Roads–Pathways for Humans, Barriers for Functioning Ecosystems” – examines issues around Ontario’s roadways and the environment
4. “Eastern Massasauga Rattlesnake Recovery Team”
* report rattlesnake sightings to http://nhic.mnr.gov.on.ca/MNR/nhic/species/species_report.cfm
(and select sistrurus catenatus)