Study Finds that Roads and Highways Directly Affect Ecology

Although they represent just 1% of U.S. land cover (an area the size of South Carolina), roads and highways directly affect the ecology of nearly 20% of U.S. land. That is the key finding of research by Richard Foreman at the Harvard Graduate School of Design, reported in the February issue of the journal

Conservation Biology. Foreman based his estimate on the assumption that a “road-effect zone” extends several hundred feet on each side of roads in rural areas and half a mile in heavily traveled developed areas. These distances are based on his own research in Massachusetts and on studies in The Netherlands. Ecological impacts of roads include blocking the migration of animals (salamanders to moose), channeling or drainage of waterways, and reduction of bird nesting due to road noise. Impacts can be mitigated in various ways, including the construction of wildlife underpasses and planting of roadsides with native vegetation.