Where is Road Ecology going?

Abstract

The building of new roads is a recognized agent of landscape transformation with several conservation implications for almost all species worldwide, threatening them with a huge variety of impacts (including some little studied, like pollution or trophic cascades). Road Ecology as an independent discipline was born twenty years ago, and since then the number of studies has not stopped growing every year. However, we wonder whether this growth has been accompanied by a diversification in scales, topics and study regions. We systematically reviewed a total of 707 studies, from journals and proceedings (ICOET, IENE, AENET, CIBIV) combined, dealing with Road Ecology. We classified the studies on the basis of: i) scale, as large (population, community or landscape levels) or local; ii) topic; and iii) country where it was carried out. Local-scale studies are roughly twice as common as those focused on large scales. Furthermore, most large-scale studies were based on methods (e.g., GIS) lacking empirical data to support their findings. Our review reveals that road ecologists have studied to date a limited range of topics, with only three of them (road-kills, barrier effects and mitigation effectiveness) monopolizing 74% of the works. Finally, 85% of studies were carried out in high-income countries. Our review suggests that Road Ecology needs to innovate in research topics, as several impacts remain understudied (long-term effectiveness of mitigation, population impacts of road-kills and barrier effects, trophic cascades). Also, focusing on others than high-income countries is of paramount importance because 90% of new roads projected for the next decades will be built in developing nations, including regions that harbor some of the last surviving wildernesses.

References:

1) Forman, R.T.T., Alexander, L.E., 1998. Roads and their major ecological effects. Annual Review of Ecology and Systematics, 207-232.

2) Forman, R.T.T., Sperling, D., Bissonette, J.A., Clevenger, A.P., Cutshall, C.D., Dale, V.H., Fahrig, L., France, R., Goldman, C.R., Heanue, K., Jones, J.A., Swanson, F.J., Turrentine, T., Winter, T.C., 2003. Road Ecology: Science and Solutions. Island Press, Washington.

3) van der Ree, R., Smith, D.J. & Grilo, C. (2015). Handbook of road ecology. John Wiley & Sons, West Sussex.