The most recent product development and launch at CSX is enabling land owners to assess biodiversity beyond just BNG, through the use of bird acoustic monitoring.
Our technical team have developed and delivered a solution that uses acoustic monitors to record, analyse, measure and monitor biodiversity of bird life. The data gathered from these devices allows us to identify bird species and quantify the frequency of individual bird calls. The data analysis techniques we’ve developed at CSX enable us to produce a range of sound ecology indices.
Taking the analysis of the bird activity indices further we may in the future be able to further develop biodiversity metrics through relating this to insect activity.
Acoustic Monitoring Analysis
When deployed on site for up to 4 weeks our acoustic monitors record bird activity at regular intervals each day to ensure fair sampling. To increase the confidence of our data analysis once in the hands of our Environmental Data Analysis team we pass the acoustic data through a noise reduction frequency band to remove wind, rain and anthropogenic noise. This is an important step to ensure species identification is accurate when the data is then run through our analytical tools.
For further quality control and verification, we carry out a manual identification step to ensure that species are being identified correctly.
We have developed this new service through deployment and ground truthing on rural estates. A process that included identifying 84 bird species and 21,091 individual bird calls through our algorithm training program.
The algorithms we’ve developed then produce a range of bird biodiversity indices.
Acoustic Diversity
Acoustic Diversity is an index that measures the diversity of sound signals and can be linked to species diversity. The higher the value, the higher the acoustic diversity.
Acoustic Evenness
Another index that can be derived from acoustic data is Acoustic Evenness which measures the evenness in a soundscape. The higher the value, the more uneven the soundscape across frequency bands.
Bioacoustic Index
Bioacoustic index measures the disparity between the loudest and quietest frequency bands and can be linked to bird abundance. High bioacoustic indices are expected to be accompanied by high acoustic diversity.
NDSI
The Normalised Difference Soundscape Index (NDSI) measures how much anthrophony and biophony is in the soundscape. A value of -1 indicates the soundscape is all anthrophony, whereas a value of +1 indicates the soundscape is all biophony.
Incorporating acoustic monitoring into BNG
The government’s Biodiversity Net Gain metric quantifies biodiversity by measuring vegetation habitats. Each habitat is given a score dependent on how ecologically valuable it is, the size and the condition.
CSX believe that biodiversity, in the traditional sense, is multi-layered and complex. It is made up of various components such as species diversity, genetic diversity and ecosystem diversity. Focusing on one proxy, e.g., habitat, does not provide a true representation of the ongoing processes and functionality of the ecosystem.
To assess, measure and monitor biodiversity beyond just BNG, through the use of bird acoustic monitoring, we can collect records on species diversity and population dynamics. Combining this with a BNG project, there is, we believe, a better understanding of how well a habitat is establishing, and consequently, more accurate ongoing biodiversity reporting.
CSX’s acoustic monitors deployed on site:
