Listening to ecosystems: data-rich acoustic monitoring through landscape-scale sensor networks

Ecologists have many ways to measure and monitor ecosystems, each of which can reveal details about the processes unfolding therein. Acoustic recording combined with machine learning methods for species detection can provide remote, automated monitoring of species richness and relative abundance. Such recordings also open a window into how species behave and compete for niche space in the sensory environment. These opportunities are associated with new challenges: the volume and velocity of such data require new approaches to species identification and visualization. Here we introduce a newly-initiated acoustic monitoring network across the subtropical island of Okinawa, Japan, as part of the broader OKEON (Okinawa Environmental Observation Network) project. Our aim is to monitor the acoustic environment of Okinawa’s ecosystems and use these space–time data to better understand ecosystem dynamics. We present a pilot study based on recordings from five field sites conducted over a one-month period in the summer. Our results provide a proof of concept for automated species identification on Okinawa, and reveal patterns of biogenic vs. anthropogenic noise across the landscape. In particular, we found correlations between forest land cover and detection rates of two culturally important species in the island soundscape: the Okinawa Rail and Ruddy Kingfisher. Among the soundscape indices we examined, NDSI, Acoustic Diversity and the Bioacoustic Index showed both diurnal patterns and differences among sites. Our results highlight the potential utility of remote acoustic monitoring practices that, in combination with other methods can provide a holistic picture of biodiversity. We intend this project as an open resource, and wish to extend an invitation to researchers interested in scientific collaboration

Ecoacoustics and multispecies semiosis: naming, semantics, semiotic characteristics, and competencies

Biosemiotics to date has focused on the exchange of signals between organisms, in line with bioacoustics; consideration of the wider acoustic environment as a semiotic medium is under-developed. The nascent discipline of ecoacoustics, that investigates the role of environmental sound in ecological processes and dynamics, fills this gap. In this paper we introduce key ecoacoustic terminology and concepts in order to highlight the value of ecoacoustics as a discipline in which to conceptualise and study intra- and interspecies semiosis. We stress the inherently subjective nature of all sensory scapes (vivo-, land-, vibro- and soundscapes) and propose that they should always bear an organismic attribution. Key terms to describe the sources (geophony, biophony, anthropophony, technophony) and scales (sonotopes, soundtopes, sonotones) of soundscapes are described. We introduce epithets for soundscapes to point to the degree to which the global environment is implicated in semiosis (latent, sensed and interpreted soundscapes); terms for describing key ecological structures and processes (acoustic community, acoustic habitat, ecoacoustic events) and examples of ecoacoustic events (choruses and noise) are described. The acoustic eco-field is recognized as the semiotic model that enables soniferous species to intercept core resources like food, safety and roosting places. We note that whilst ecoacoustics to date has focused on the critical task of the development of metrics for application in conservation and biodiversity assessment, these can be enriched by advancing conceptual and theoretical foundations. Finally, the mutual value of integrating ecoacoustic and biosemiotics perspectives is considered

Ecoacoustics: the Ecological Investigation and Interpretation of Environmental Sound

none2sìThe sounds produced by animals have been a topic of research into animal behaviour for a very long time. If acoustic signals are undoubtedly a vehicle for exchanging information between individuals, environmental sounds embed as well a significant level of data related to the ecology of populations, communities and landscapes. The consideration of environmental sounds for ecological investigations opens up a field of research that we define with the term ecoacoustics. In this paper, we draw the contours of ecoacoustics by detailing: the main theories, concepts and methods used in ecoacoustic research, and the numerous outcomes that can be expected from the ecological approach to sound. Ecoacoustics has several theoretical and practical challenges, but we firmly believe that this new approach to investigating ecological processes will generate abundant and exciting research programsrestrictedSueur, Jérôme; Farina, AlmoSueur, Jérôme; Farina, Alm

Low cost (audio) recording (LCR) for advancing soundscape ecology towards the conservation of sonic complexity and biodiversity in natural and urban landscapes

Low cost (audio) recorders (LCRs) represent a new opportunity to investigate the sonic complexity of both natural and urban ecosystems. LCRs are inexpensive sampling audio recorders which have the external shape of a universal serial bus (USB) flash drive, and are composed of a microphone, an analog-to-digital converter, central processing unit with permanent internal non-volatile memory, rechargeable battery, and a USB connection. The reduced dimen­sions allow the device to be deployed inconspicuously within any environment, in any config­uration and for an extended time period. This investigation tested a specific type of LCR (UR-09) with a spectral range of 8 kHz -sufficient to cover the acoustic range of most western Palearctic songbirds. The reliability of the UR-09, compared with other commercial recorders (Zoom H4 and Song Meter SM1) and based on the quality of recordings quantified by the Acoustic Complexity Index (ACI), was tested and confirmed. An example of the application of LCRs is presented in an evaluation of the audio patterns occurring during dawn and dusk choruses within a forested ecosystem. Results of this investigation are encouraging and a new generation of LCR devices is currently being designed with real-time acoustic data processing capabilities, timer programmability, a larger frequency range and wireless communication compatibility. LCRs are revealed to be ideal instruments to conduct surveys in fragile or protected areas and also in urban environments. Moreover, due to their low cost, they can be used to encourage research in soundscape ecology, especially within developing countries, where large areas can be monitored by professionals or incorporating citizen science models of data collection. Keywords Soundscape ecology . Low cost (audio) recorders . Acoustic complexity index . Acoustic monitoring . Citizen science . Urban ecosystem