Agriculture Reference
In-Depth Information
14
Acoustic Observations in
Agricultural Landscapes
Stuart H. Gage, Wooyeong Joo, Eric P. Kasten,
Jordan Fox, and Subir Biswas
Sounds emanating from various habitats and ecosystems provide a rich source of
information to interpret ecological phenomena at multiple scales. Acoustic com-
munication is a fundamental property of many animals for breeding and defending
territories (Fletcher 1953, Peterson and Dorcas 1994), and acoustic signatures can
be used to measure the spatial and temporal distributions of vocal organisms in eco-
systems (Kroodsma and Miller 1996, Pijanowski et al. 2011a). Ecosystem sounds,
in general, create a
soundscape
, made up of acoustic periodicities and frequencies
emitted in aggregate from an ecosystem's biophysical entities (Schafer 1977, Truax
1984, 1999, Qi et al. 2008). Soundscapes can be partitioned into anthropogenic,
biological, and physical sources (Napoletano 2004, Qi et al. 2008, Pijanowski et al.
2011a, Joo et al. 2011). They can then be further subdivided to provide valuable
insights into the ecology of vocal organisms and their habitats, including their
diversity and abundance, as well as phenological events such as seasonal arrivals,
dates of reproduction, and breeding communication behavior.
Interpreting animal sounds has been used for many years to survey vocal organ-
isms. For example, the U.S. North American Breeding Bird Survey—one of the
largest long-term, national-scale avian observation programs—has been conducted
for over 30 years by observers using both auditory and visual cues (Bystrak 1981,
Robbins et al. 1986). The North American Amphibian Monitoring Program iden-
tifies amphibian species primarily by listening for their calls at night (Weir and
Mossman 2005). Recent advances in sensor networks enable the large-scale, auto-
mated collection of acoustic signals in natural areas (Estrin et al. 2003, Porter et al.
2005, Pijanowski et al. 2011b, Aide et al. 2013, Ospina et al. 2013). The systematic
and synchronous collection of sound recordings at multiple locations, combined
with ancillary measurements such as light, temperature, and humidity, can produce
an enormous volume of ecologically relevant information.
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