Agriculture Reference
In-Depth Information
Soundscape information has the potential to increase our understanding of eco-
system change if sampled over appropriate time intervals (Truax 1984, Wrightson
2000, Sueur 2008). The analysis of entire soundscapes may also produce valu-
able information about the dynamics of interactions among ecological systems in
heterogeneous landscapes (Carles et al. 1999). Further, rapid analysis enables the
timely delivery of important environmental information to natural resource manag-
ers and can promote public involvement through public access to information about
nearby and distant environments.
Automated, distributed acoustic measurements via sensor networks provide
additional benefits to ecology and the environmental science community. First,
analysis of observations collected through continuous monitoring at fixed sites can
reveal spatiotemporal patterns that cannot be captured using site-by-site observa-
tions (Gage et al. 2004, Gage and Axel 2013). By monitoring soundscapes continu-
ously from fixed locations, acoustic information can reveal ecosystem change over
scales of days to years (Truax 1984). Second, because acoustic monitoring systems
can simultaneously monitor multiple locations, acoustic variances can be compared
to environmental heterogeneity (Thompson et al. 2001, Michener et al. 2001, West
et al. 2001). Third, microphones can collect data from all directions simultaneously
despite visual obstructions such as trees or buildings, and at all times of day includ-
ing night. Finally, recording technology can operate in the field unattended, thereby
allowing observations to be made without the interference generated by human
presence (West et al. 2001).
Here, we illustrate the use of older recording technology (tape recorders with a
clock used in 2005) and the subsequent development of wireless monitoring tech-
nology (sensor-transmitter-receiver used in 2007)  to measure the soundscape,
transmit the sound to a remote computer, and analyze it to understand the spa-
tial and temporal variability of sounds emanating from ecosystems in the Kellogg
Biological Station Long-Term Ecological Research site (KBS LTER). In particular,
we describe the design, development, and deployment of an automated acoustic
recording system and then its application to examine ecological phenomena in a
complex agricultural landscape.
Soundscape Taxonomy
The sounds emanating from an ecosystem can be treated as the transmission of
signals that carry information (Shannon 1948, Raisbeck 1964). The organism or
force generating a sound acts as the encoder and transmitter of a signal that travels
through a medium such as air or water. An organism receives the acoustic signal
and then registers and decodes it into information.
Acoustic signals can be generally classified as either natural or human-induced
sounds (Schafer 1977). Krause (1998) called the natural sounds biophony .
Napoletano (2004) further classified soundscapes as biological, geophysical,
or anthropogenic (Fig. 14.1). Biological sounds can be intentional or incidental
signals. Intentional signals are produced by organisms that wish to communicate
information such as mating or distress calls. Incidental signals may contain useful
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