Acoustic monitoring

Sound is revolutionizing the monitoring of biological diversity. Acoustic monitoring can be used both on land and in water, and gives us knowledge about nature in a fast and cost-effective way. NINA uses acoustic monitoring in several pilot projects. 

New and promising method

The acoustic monitoring of species, ecosystems and human activity is a new and promising method for efficiently monitoring the environment in general. With the help of sound recordings from an ecosystem, we can, for example, detect alien or endangered species, describe species phenology, and document changes in ecological status or human impacts on nature.

Acoustic monitoring also works when visibility is poor, such as in murky waters, dense forests, in fog or at night. Monitoring relies on small recorders equipped with a microphone or hydrophone, called sound loggers. The loggers are equipped with a battery and solar panel, so they can operate for a long time without supervision. Since the system requires little maintenance, researchers can avoid repeat visits that can disturb the area being monitored, which makes this approach particularly suitable for harsh Norwegian conditions.

Although the technology has been used for a long time in studies of individual species, it is only recently that acoustics have become more widely used. Advances in computer technology, digitization and artificial intelligence provide great opportunities to further develop and complement existing methods for data collection and analysis.

In a time of rapid environmental change, remote sensing methods are especially important for monitoring and nature management because they continuously produce data streams that can be analysed across different spatial and temporal scales.

NINA is testing bioacoustics in several pilot projects

Acoustics is a very useful method for addressing a number of research questions, and NINA leads or participates in many national monitoring projects where both bioacoustics and ecoacoustics could contribute new and important information.

The inclusion of sound can provide valuable additional information and a broader database for assessing biodiversity and the state of health in different ecosystems.

Insect monitoring

NINA recently conducted a pilot study in connection with a national insect monitoring project. Here, the diversity of the soundscape was compared to the diversity documented in DNA collected from insects.

Alien fish

In another project, the idea has been to identify and attract the round gobi (Neogobius melanostomus). This is an alien fish species that has not yet been detected in Norway, but which is expected to be introduced via ship ballast water. Since the round gobi makes a lot of noise, it is well suited to this kind of pilot project.

Several other projects are being planned, including microphone recorders set up in combination with a game camera, to see how human activity affects wildlife.

The digital revolution allows for many possibilities. With the technology and analysis methods available today, we can already monitor nature at a large scale using sound. By developing the technology further, we can find even better approaches for nature monitoring programmes.

Bioacoustics as a management tool

Nature is facing increasing threats from the influence of human activity, both in Norway and globally. This is why we need to know more about how human activity contributes to influencing the state of ecosystems.

Efforts are well underway to ensure that Norway’s ecosystems are in good condition, mainly through preparing comprehensive freshwater and marine management plans. Work on comprehensive management plans for terrestrial ecosystems remains in its infancy. In terrestrial ecosystems, we assess conditions using knowledge-based systems for determining what factors contribute to a good ecological status. Understanding the current state of ecosystems forms the basis for the preparation of management plans, for which we need more information.

The increased need for information requires better use of existing data, such as through the increased availability of relevant time series on biodiversity, but also better statistical methods and models. There is also a need to develop monitoring methodologies, such as those relying on remote sensing and ground-based sensors.

Acoustic monitoring of fauna and of human activity is a promising method to make monitoring more efficient, but also as a way to collect new information to increase our understanding of how nature is affected by human activity.

Recent developments in computer technology, digitization and artificial intelligence provide great opportunities to further develop and complement current methods for data collection and analysis.

Biodiversity is threatened by climate change, habitat degradation, invasion of alien species and overexploitation, all of which can be investigated using an acoustic approach. Changes in the phenology of plant and animal populations can lead to changes in the soundscape throughout the year, associated with many different ecological functions (such as reproduction, spawning, predation or migration). Habitat degradation, eutrophication events or overexploitation can cause changes in the amount of sound from both terrestrial and aquatic species. Alien species can be identified by the sudden presence of sounds that were not previously common. Monitoring both individual species and entire ecosystems can provide important information for management, and is particularly suitable for otherwise inaccessible environments.

Sensor technology and routines for data processing are continuously being developed, and are constantly improving. Modern machine-learning techniques make it possible to extract detailed information from the soundscape, which makes acoustics an important contribution to the toolbox for monitoring the Norwegian environment.