Benefits and impacts of road removal

federal lands to facilitate resource extraction, recreation, and transportation (Havlick 2002) – enough to drive to the moon and back. While these roads provide important services, their construction and presence can also influence the hydrology, geomorphology, and ecosystem processes. They can substantially alter hillslope hydrology by reducing soil infiltration, concentrating water through road drainage structures, and converting subsurface flow to surface flow (Luce 2002). Overland flow can cause geomorphic changes, including chronic erosion (Megahan and Kidd 1972), extended channel systems (Wemple et al. 1996), and increased risk of landslides (Swanson and Dyrness 1975), thereby decreasing aquatic habitat quality. Roads also influence the ecology of terrestrial and aquatic ecosystems through direct habitat loss, fragmentation, and associated human impacts as a result of increased access (Wisdom et al. 2000). Recognition of these wide-ranging effects has recently thrust roads into the forefront of research, resulting in the publication of books (eg Forman et al. 2003; Havlick 2002), reviews (eg Gucinski et al. 2001; Trombulak and Frissell 2000), special journal issues (eg Conservation Biology 14[1], Earth Surface Processes and Landforms 26[2 and 3], and Water Resources Impact 3[3]), and thousands of peer-reviewed studies. Increasingly, roads are being removed to mitigate these problems. However, to date surprisingly little attention has been given to the shortand long-term benefits and impacts of road removal. Here we describe three methods of road removal, summarize research that has been conducted, and identify knowledge gaps and research needs in this emerging field.