Road Mortality on Ontario Highways

 

As you drive along a highway through the Muskoka region you may notice something peculiar on the highway. Something like a road bump, but a bit more green, reptilian, and moving.

Turtles, as well as frogs and other species are at risk of death from highway collisions with cars.

Unfortunately, these small and beloved pond creatures don’t stand a chance against a literal ton of metal, glass, steel, and plastic moving at more than 100 kilometres per hour.

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Jackie Litzgus is a professor in the Department of Biology and a faculty member at Laurentian University’s Centre for Evolutionary Ecology and Ethical Conservation.

Jackie’s lab uses basic and applied science approaches in both the field and the lab to address questions related to the evolutionary ecology and conservation biology of reptiles. Her lab looks at maternal investment, spatial and road ecology, and habitat selection, amongst other areas.

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David Lesbarrères is an Associate Professor in the Biology Department and the Dean of Graduate Studies at Laurentian University.

David’s research on ecology and evolution focuses on host-parasite interactions and road ecology. Combining fundamental and applied evolutionary ecology, his work has lead to to projects looking at infectious diseases, conservation genetics, road mitigation techniques, and mass-mortality events.

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Jackie and David took some time to answer a few questions we had about protecting reptile and amphibian species from untimely death as a result of highway collisions on Ontario roads.

What is the field of road ecology?

 

JL: Road ecology is the study of the impacts of roads on flora and fauna, and the development of strategies to mitigate their negative effects.

 

DL: Road ecology is a relatively recent field, starting in the mid-nineties when scientists tried to understand how far the road effect was extending beyond the asphalt. While we have a good understanding of the various effects associated with roads, from the loss of biodiversity to the genetic isolation of populations, much of today's road ecology research focus on improving our mitigation strategies.

 

 

What are the biggest road ecology issue in Ontario?

 

JL: A high priority right now for Ontario is implementing mitigation whose effectiveness has been rigorously assessed and quantified. There is also a need for financial support to undertake such assessments and implement such mitigation.

 

DL:  In my opinion, the biggest challenge is to make road ecology part of the road design and construction. Too often it has been an afterthought in the process, leaving only a few options once the road is in place. Knowing that the density and expansion of roads is only to increase, the location of roads and the mitigation of their effects should be scientifically—and not just economically—planned from early on.

 

Why do certain at-risk species cross highways?

 

JL: Individuals tend to cross because their migration and dispersal paths intersect highways. These roadways have fragmented habitats used by turtles, so in order to access the resources they need, turtles are forced to cross roads.

 

DL: Amphibians are also heavy users of roads as they migrate long distances through the year, which puts them at risk of road mortality.

 

Why are reptiles and amphibians in particular at risk of road mortality?

 

JL: Adult female turtles are typically those making migrations for nesting. Reproductive females are the most important life stage for population persistence—when they are killed on roads, all their future offspring are lost as well. And because turtles live for decades, that’s a lot of recruitment that won’t happen. Populations can decline quickly as a result of loss of females.

 

DL: In the case of amphibians, they are equally affected by roads as they migrate from their hibernation sites to their breeding ponds in high numbers in the spring (and vice-versa in the fall). This makes them very susceptible to road mortality. In a project conducted in Presqu'Ile Provincial Park over 4 summer months, we recorded more than a thousand frogs killed over a five kilometre stretch of road. Not only are these numbers striking, but also very little is known about the further consequences of this death toll on the populations.

 

 

What role do scientists play in protecting these species from road mortality?

 

JL: Scientists can collect and analyze the data to rigorously inform mitigation. Funds to support conservation actions are limited, so we should back up decisions with good data, to effectively use those limited dollars.

 

DL: The use of scientific data in infrastructure planning is not new, yet ecological data has been far removed from the conversation for too long. Economists, engineers, planners, and policy makers have all made use of some data when planning road construction; however, it is time that ecologists take part in the conversation so that roads are not another factor in the decline of biodiversity worldwide. By being involved early, ecologists can study where the roads will have less impact on wildlife and provide the best design to accomodate movements across the roads. And in the case of road rehabilitation, they can inform where the mitigation is best located to suit the needs of the existing species.

 

Can you give a brief description of the work you are doing in this field and what results you have seen so far?

 

JL: What we and others have found is that the key to successful road mortality mitigation is a good fence design, one that effectively funnels the animals to ecopassages—structures that allow animals to bypass infrastructure like roads. And these fences have to be robust. If there are holes in the fences, the animals will go through them and get stuck on the unsafe road-side of the fencing—the exclusion fencing has to truly be excluding.
 

Exclusion fencing on an Ontario highway.

 

DL: There are several parts of a road issue that my group has been involved, from determining the hotspots of road mortality (and thus where to mitigate in priority), the design and testing of wildlife passages, exclusion fencing and other techniques to protect species from road mortality, and finally to test these measures in situ so that we improve our understanding of what works and what does not. Ultimately, I am working to provide rigorous data allowing decision makers to agree on gold-standards instead of ad-hoc solutions decided at the last minute as is too often the case.

 

What can motorists do to protect these species from mortality?

 

JL: Motorists can try to avoid hitting turtles on roads. And if possible, taking the time to help move turtles across the road—if it is safe to do so—will help protect both individuals and populations.

 

DL: Motorists need to be informed and sensibilized to the idea that their behaviour matters. We are making roads safe for them, they can in turn help make the roads safe for wildlife.

 

 

What can individuals who live along roads/live in areas with reptile populations do to protect species from road mortality?

 

JL: Along with the suggestions above, it’s helpful for individuals to participate in outreach opportunities to spread the word about the problem of road mortality.

 

DL: If residents notice a lot of mortality of nearby roads, they should lobby their local authorities to mitigate this issue. In Europe, several resident groups take upon themselves to develop outreach programs and to actively protect the movements of amphibians and reptiles during their migration. Not only it is a fun activity, but combined with outreach, it can provide the platform for long lasting changes in our policies for road development.

 

What are some ways policy changes could help protect these animal communities?

 

JL: The biggest help from a policy perspective is the enforcement of endangered species legislation. In addition, following-up on any overall benefit strategies will help protect individuals and populations.

 

DL: In my opinion, the biggest change that would make a difference is to enforce the early participation of ecologists in the design of the future roads. Only when these infrastructures are built with the equal protection of biodiversity and people in mind will we see reduction of this threat to amphibians and turtles.