A landscape's acoustic signature is a unique component of the evaluation of its function (Krause 1987,Krause 2002; Schafer 1977, 1994). While the vocalizations of organisms historically have been studied in an abstract individualized manner, our preliminary evaluation of recorded soundscapes as a means to assess landscape health was focused on the recording of audio samples within the landscape. New methods of evaluating the stability of a landscape from the perspective of bioacoustics combine the sound-producing properties of all the vocal organisms within that habitat to establish base line data of the soundscape signature. A soundscape is a region of acoustic activity homogeneous in a feature of interest (Schafer 1977, 1994). In most environments today, soundscape signatures are comprised of two natural components, biophony and geophony, and a probable human component that includes the third, anthrophony. Biophony is the combined sound that living organisms produce in a given habitat. Geophony is comprised of geophysical sounds in the environment, such as the effect of wind in trees or grasses, thunder, water flow, earth movement, etc. Anthrophony is usually comprised of human-generated mechanical sounds, such as signals from aircraft, automobiles, generators, snowmobiles, jet-skis, radios, television sets, boom boxes, or automobile sound systems. This classification will assist in identifying the introduced elements that may cause stress or change not otherwise noticed by traditional visual evaluation. Biophony may also be used to augment data collected by other means. The scope of this project has been to record a limited number of base line recordings of acoustics sampled from each of four sites representing 4 key landscapes in SEKI, and to evaluate them with regard to the indicators present when submitted to broadband spectrogram evaluation.

The Niche Hypothesis predicts a positive correlation between species composition and soundscape structure in terms of time, frequency, and amplitude. When a habitat reaches dynamic equilibrium, the spatial structure of the acoustic spectrograms illustrate complex features (both frequency and temporally based) indicative of the relationships between the vocal organisms. Using this as an initial framework, we began to sample the acoustic signatures of four distinct landscapes in SEKI and examine the samples for defining differences and distinguishing features in the soundscapes (Krause 1987,Krause 2002).

Wild Sanctuary, in cooperation with Michigan State University's Remote Environmental Assessment Laboratory (Prof. S. H. Gage) conducted the soundscape assessment in SEKI.

The objectives of the study were to:

1. Record acoustic features (digital recording) of four different landscapes within Sequoia National Park from October, 2001 to July, 2002, to provide a measure of diurnal and seasonal variation within natural soundscapes associated with animal and insect vocalizations within the park
2. Process acoustic samples and characteristics (given season, weather, time of day/night, etc) of each landscape chosen for study;
3. Begin creation of an index of acoustic dynamics (vocalization density, vocalization discrimination, overall amplitude envelope, duration of choruses, etc.) within each habitat to correlate it with more traditional landscape ecology indices;
4. Calculate the potential of bioacoustics as a tool for assessing the health of an ecosystem, possibly by correlating the results with existing data to determine habitat degradation as well as regeneration by examining the degree of niche partitioning in the samples; and
5. Begin to quantify the effect of introduced noise on biophonies.