Frank T. Awbrey
Biology Dept., San Diego State Univ., San Diego, CA 92182-0057
Regulators are proposing to set simplistic limits for anthropogenic noise in natural environments. These proposed limits specify only SPL, without regard to the method of measurement, frequency or time weighting, normal ambient levels, or spectra. In some cases such limits may be inadequate, but in others they may be much too severe, resulting in unrealistic restrictions on human activities, including scientific investigations, without real benefit to the animals. Realistic limitations on noise level should incorporate information on the time history and spectrum levels of the noise and the animals' communication signals, with estimates of hearing threshold curves. This paper outlines an initial effort to devise such a model and to estimate how seriously noise of different kinds will limit communication.