The soundscape approach for the assessment and conservation of Mediterranean landscapes: principles and case studies
Usually, landscape quality is assessed after several concurrent geographical, ecological and aesthetic factors have been surveyed. Unfortunately, the sonic environment or soundscape is often neglected or only marginally considered in such a process, meaning that important information on the functioning of environmental systems is lost.
The soundscape is considered to be the result of the sonic information that emerges from different geophonies, biophonies and anthrophonies across a landscape. Geophonies are produced by wind, water waves, thunder, volcano eruptions, etc. Biophonies, meanwhile, are the result of vocal animals, and anthrophonies are produced by human technology. The spatial distribution of such sonic components is coupled with the structures of landscapes, thereby producing patterned sonic patches or sonotopes. The complexity and variety of sonotopes are good indicators of the ecological conditions of a landscape.
The simplification of the landscape structure, the degradation of the ecotopes, the fragmentation of forest covers, and the processes of land abandonment are immediately reflected in the structure and spectral composition of a soundscape. Habitat destruction and noise pollution are contemporary negative processes having an impact on the quality and complexity of a soundscape.
In particular, in the Mediterranean basin, the increasing intrusion of human activity that is connected to urban sprawl, transport infrastructures, and trading and industrial logistics has a major impact on the quality of the sonic environment, leading to the impoverishment of the spectral variety of frequencies due to the loss or displacement of many vocal species (insects, amphibians, birds and mammals).
The soundscape methodology is supported by: modern digital sound recording devices, the opportunity to store and browse a great deal of acoustic information, and new metrics with which to process a significant amount of acoustic data in a reasonable period of time. The recent availability of low cost digital recorders and the offer of public-domain software (e.g. SoundscapeMeter) represent a further positive aspect that encourages the application of this methodological approach.
The soundscape analysis is powered by the use of several digital recorders operating at the same time and organized in a regular matrix, allowing the structure of a landscape at different scales of resolution to be intercepted. The non-invasiveness of the sonic survey and the opportunity to characterize a soundscape with a modest taxonomic competency create favourable conditions for the widespread application of soundscape analysis to landscape assessment and conservation.
Examples of the application of the soundscape approach and the related methodology will be presented with respect to some Italian sub-Mediterranean rural landscapes (e.g. mountain pastures, beech woodlands and Mediterranean maqui) that are facing land abandonment and an intense fire regime.
The results obtained from different sampling intensities and with the use of different recording devices are presented in this typology of Mediterranean landscapes. The potentiality of the soundscape methodology for assessing landscape quality and for offering indications for protective action in such valuable landscapes is also demonstrated.