Abstract: World-wide road expansion has engendered concerns regarding road effects on the landscape, particularly on vulnerable habitats and wildlife. Salamanders, critical components of ecosystems and useful bioindicators, are vulnerable to road impacts due to seasonal migrations, habitat loss, and reliance on stream health. Research has examined road impacts on salamanders but has largely viewed paved roads with fewer studies comparing road types or examining non-passenger vehicle paths. Here we summarize 155 studies on road effects on salamanders, including paved and unpaved roads, logging roads and skidder trails, railroads, hiking trails, and powerlines. We examine trends in road type, study area, location of study, salamander habitat association, and results; summarize current knowledge; and identify knowledge gaps. For literature searches, completed January 2023, we used Web of Science and collected papers related to salamanders and roads. We then reviewed and summarized the papers and used Chi-squared tests to examine trends. We found that roads had majority negative effects on salamanders through direct mortality, damaging habitat, and fragmenting populations. Higher traffic and wetlands proximity increased negative impacts, although even long-abandoned logging roads showed negative effects. Positive effects were rare and related to habitat creation along roads, which may be useful for mitigation of road effects. Additionally, well-designed under-road tunnels with drift fencing were an effective mitigation strategy for salamanders. Non-passenger vehicle roads were critically understudied, as were mitigation strategies such as bucket brigades and habitat creation. Considering the expansion of road networks and declines in salamander populations, managers must account for road effects at landscape scales. Managers should incorporate mitigation strategies and work to reduce road impacts on vulnerable wildlife.
