Assessing noise impacts on wildlife under the National Environmental Policy Act.

Abstract

Under the National Environmental Policy Act, authors must address environmental impacts of various anthropogenic actions on wildlife. One such impact of increasing awareness and concern is effect noise on wildlife, both during construction and operation of the project. However, biologists often have difficulty in understanding the fundamentals of acoustics and noise analysts often have difficulty in understanding the biological implications of increased noise on wildlife. As a result, inappropriate weighting metrics (such as A-weighted decibel) or time descriptors (e.g., community noise equivalent level) are often used erroneously to assess noise impacts on wildlife. Noise exposure thresholds on wildlife exist for marine mammals and fish, as mandated by the National Marine Fisheries Service. However, no such thresholds exist for terrestrial wildlife. This talk provides specific examples of how noise impacts on wildlife have been assessed using GIS-based technology, industry-accepted noise propagation models, and peer-reviewed literature in the absence of management guidelines. Examples include assessing construction noise impacts on the California coastal gnatcatcher in southern California, aircraft noise impacts on sage grouse in central California, and helicopter disturbance on caribou in Alaska.