Grant: Discovery Grants Program - Individual

Over the past 100 years roads have become a dominant landscape feature and this infrastructure continues to expand. Recently, concerns about the potential effects of roads and traffic on wildlife have been increasing. For example, roads and road kill are considered significant threats in the listing of several threatened species in Canada, and road mortality is the largest single component of mortality for some wildlife populations. However, to date there are almost no studies evaluating the relationship between road density and wildlife population sizes. My first objective is to determine the size of the impact of roads and traffic on wildlife populations, independent of and in comparison to other landscape changes such as habitat loss. Species that occur in low numbers, range widely over the landscape, and move onto roads irrespective of oncoming traffic should be most affected by traffic mortality. Species that avoid roads, i.e., they do not attempt to cross them, will be less susceptible to traffic mortality, but they may become cut off from required resources on the other side of the road, or their populations may become fragmented into smaller populations that are more vulnerable to extinction. On the other hand, species that do not avoid roads but avoid individual vehicles, i.e., wait for a break in traffic to cross the road, should be least susceptible to both road mortality and the barrier effects of roads. To date there has been almost no research aimed at testing these ideas. My second objective is to determine what kinds of organisms are most affected by roads and traffic at the population level. The proposed research directly addresses two important applied questions: (i) should government agencies (e.g., environment and transportation ministries) try to mitigate the impacts of roads and traffic on wildlife, i.e., are these effects generally large relative to other human impacts on wildlife, and (ii) in what situations should road expansion be avoided and current road effects be mitigated?