| Roads and traffic disturb nearby bird habitats by creating an additional habitat edge, traffic noise, increased mortality, and other forms of pollution. We investigated declines in bird species richness near high traffic roads and controlled for an edge effect by conducting bird surveys along two transects, forest edge and forest interior, which ran perpendicular to the road. Traffic volumes were obtained at each bird survey location to test if noisier areas had fewer species. For both transect types there was a positive relationship between species richness and distance from the roads, with species richness increasing to a threshold distance of 300 m from the roads. At a given distance, sites with louder traffic noise did not have fewer species. Species with lower dominant call frequencies were not the species most affected by roads. Our results show that roads, independent of edge effects, a re causing a decline in bird species richness. |
