Modeling of the Relationship Between Bird Distribution, Traffic Noise and Other Environmental Variables Along Asian Highway in Golestan National Park

This paper examines the likely relationship between traffic noise and other environmental variables and bird distribution. The study was conducted in September 2012, along Asian Highway in Golestan National Park. The sampling stations were selected in 76 points using Systematic-Random method at various distances between 0-250 meters from the road. Birds and environmental variables were sampled in a radius of 25 meters from each point. In each of the sampling points and in the center of the plot, birds and other variables such as temperature, relative humidity, traffic noise, number of vehicles (light, heavy and medium-weight vehicles), number of horn beeping, height, the sound barrier height, width of the road, slope and the geographical size were measured. All data were recorded during a week of the year with the heaviest traffic and noise pollution. The birds as dependent variables were divided into three guilds namely Primary Cavity Nesting Birds, Secondary Cavity Nesting Birds and non Cavity Nesting Birds and accordingly, three prediction models were developed. The result of multivariable linear regression analyses showed that in all of these models the most important factor affecting birds is traffic noise.