Passages For Wildlife! How To Reduce The Dramatic Effect Of Roads On Biodiversity By Margaux d’Ambly and Andréa Poiret Landscape fragmentation is known to be one of the main causes for the decline of biodiversity worldwide. The multiplication of transport infrastructures over the last decades has changed the landscape drastically, heavily affecting natural ecosystems and wildlife. Highways are acting as physical barriers, which hampers wildlife movements and disrupts habitat connectivity. Additionally, collisions with vehicles are direct sources of wildlife mortality, which can be catastrophic to some animal populations. The “barrier effect” The survival of animal populations relies on their ability to move freely across the landscape. Indeed, animals are always searching for food, a shelter or a partner to reproduce with. The construction of transport infrastructures enhances a “barrier effect,” induced by the fencing of roads and/or the noise and light pollution generated by car traffic. Consequently, the landscape is divided into small isolated “islands,” where natural habitats and populations find themselves disconnected from each other’s. This fragmentation of the environment reduces the quantity of available habitats, resources and sexual partners. Population isolation increases consanguinity, which weakens animal populations and can possibly result in local extinction in the long-term.