The lost road: Do transportation networks imperil wildlife population persistence?

The global road network is rapidly growing associated with human economic development. This growthalso entails a high toll for biodiversity, with several well-documented negative impacts on differentspecies. However, there is still a great lack of knowledge about the effects of roads on the persistenceof wildlife populations. Here, we aimed to summarize our current knowledge on this topic, based onsystematic reviews. We found that only a small proportion of studies (8%) focused on the effects of roadson population persistence. Most of these studies were about large mammals and were performed in high-income countries. Furthermore, these works studied only 2% of those species identified by the IUCN RedList as threatened by roads. Overall, our results show that we are far from understanding how roads affectthe long-term viability of wildlife populations inhabiting road-effect zones. Addressing this challenge willrequire modifying our conceptual perspective, from short-term to long-term studies, from single roadsections to focusing the landscape scale, and strive to obtain empirical data to support sound analysesto assess how road impacts affect the survival of wildlife populations, namely with information requiredto perform approaches such as population viability analyses. We highlight some key studies from ourreviews that have addressed this global conservation concern with population-oriented approaches.