The importance of U.S. national forest roadless areas for vulnerable wildlife species

Abstract

Inventoried roadless areas (IRAs) in national forests in the contiguous United States (CONUS) are public lands that are ecologically intact and could be prime candidates for addition to the protected-area system, thereby contributing to the goal of protecting 30% of the Earth by 2030. Despite calls both to protect roadless areas and to downgrade them, we know surprisingly little about the importance of IRAs as habitat for vulnerable wildlife species. We assessed the importance of IRAs—in total and individually—as habitat for wildlife species of conservation concern (SCCs) and, for context, compared their habitat value to that of other national forest lands and CONUS lands in general. We also quantified how well the protected-area system would provide habitat for wildlife SCCs if all unprotected IRAs were added to it. Of the 537 wildlife SCCs in CONUS, 308 species (57%) have at least some suitable habitat in one or more IRAs. The median IRA contains suitable habitat for 10 wildlife SCCs, with a maximum of 62 wildlife SCCs. Despite their geographic and elevational clustering and predominance of a single biome type, IRAs provide a larger proportion of suitable habitat for multiple wildlife SCCs than non-IRA CONUS lands. The median number of wildlife SCCs’ suitable habitat per 900-m2 pixel is also slightly higher in IRAs than in most national forest wilderness areas, national monuments, and other currently protected areas. If all IRAs were added to the protected-area system in CONUS, there would be a substantial decrease (−38) in the number of wildlife SCCs that are currently considered “poorly represented” in protected areas. In this study we provide quantitative information about the importance of IRAs as habitat for vulnerable wildlife species so that stakeholders, agency staff, and lawmakers can make informed choices about where to invest limited resources for conservation.