Train noise mapping: sound in the landscape and implications for wildlife

Abstract

Noise pollution is a concern both to wildlife conservation and to human health. Much research has been done on the effects of road noise on breeding birds in the adjacent landscape, but the effects of train noise have not yet been studied. I determined the pattern of amplitude decay of train noise in the natural environment. Full spectrum sound was recorded at 25, 50, 100 and 200 m intervals on transects perpendicular to a major railway line in the North of England. Recordings were made of a range of train models passing through woodland and open ground. Decay curves were determined for full spectrum noise, and specifically over the frequency range of bird calls, to assess the potential for call masking and other auditory interference for birds. There was no significant difference in the amplitude decay curve between woodland and open ground. Some small differences (<10%) were found between some train models at some sites. Sound in the higher frequency bird call band deteriorated with a steeper curve than full frequency spectrum sound. Rail noise amplitude (relative to that at 25 m) deteriorated to 50% at 200 m for full spectrum and to 30% in the bird call frequency band. The road network in England is not only more extensive than the rail network, but generates almost continuous noise pollution over a much greater distance (amplitude falls to 50% at 900 m) relative to the intermittent noise of rail. This study highlights a previously unforeseen environmental benefit of rail over road.