Biology Reference
In-Depth Information
5.1
Introduction
The recent changes in the global economy, human migratory fluxes, and occupying
new land for development has modified the traditional landscape structure, increas-
ing humanity to a new level of noise exposure that is considered a form of invasive
environmental pollution. Quiet areas are associated with relevant ecological values,
and in national parks and protected areas their value is compared to clean air
quality.
The perception of the sonic context requires a specific recognition that has its
origin either in the genetic code or in cultural individual experience. In other words,
sonic perception requires a specific capacity by every perceiving agent (humans and
nonhuman animals) that must be trained. For this, measurements of sound magni-
tude [e.g., A-weighted sound pressure level (
L
Aeq
)] is not sufficient to characterize
the sonic ambient, and other factors have to be considered.
The sonic environment, as a neutrality-based soundscape (sensu Farina
2006
),
exists in terms of energy and information but to be perceived, which requires a
species-specific cognitive approach that converts such sonic energy to meaningful
information.
In fact, the sonic environment can be described in at least three levels of growing
complexity.
The first level is dominated by the physical properties of the sounds, ranging
from infrasound to ultrasound frequencies.
The second level is the level of the physiological perception of every single
species. For instance, in this level human perception is limited to 20-20,000 Hz, but
whales can heard infrasound ranging from 20 Hz down to 0.001 Hz, and bats in
contrast can perceive ultrasonic frequencies up to values of 210 kHz.
A third level pertains to the interpretation of the sounds according to genetic or
cultural/social decodification of the sonic signals (Fig.
5.1
). At this last level
pertains the concept of the sound ambient environment (SAE) where human
experience and acoustic characters are considered at the same time. In conclusion,
perception of the sonic ambient requires, from the receiver, action dependent on
genetic and cultural mechanisms.
The sonic environment is associated to aesthetics agreeing with human well-
being in outdoor and indoor situations. To recover the sense of well-being is
increasingly important for our stressed everyday life. Reflection and relaxation
are two functions that are necessary for our psychological comfort and equilibrium
and which can be achieved only in special places we recognize as tranquil, quiet, or
in other terms, “beautiful.” Such places are not common around us. In many cases
such places have vanished with the spread of infrastructures and urbanization, and
developing new tranquil spaces combining acoustic and visual components of the
environment has become a priority.
The state of “tense arousal” was essential for our ancestors to escape predation,
enabling them to cope constantly with environmental variables and every type of
event. Of this heritage, modern people have retained only a few components. Of
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