This dataset contains audio files from Samford Peri-Urban SuperSite. Samford Peri-Urban SuperSite was established in 2010 in remnant fringe eucalypt forest, near urban development in the Samford Valley. The upper storey is dominated by Corymbia intermedia, Eucalyptus siderophloia and Lophostemon suaveolens. For additional site information, see Samford PeriUrban SuperSite
A recorder was initially set up between October 2011 and July 2012 to collect acoustic data within the site. A second recorder was set up in 2013. This collected audio data for a total of 12 hours per day, split between six hours around dawn and six hours around dusk. The recording schedule aimed at capturing morning and evening bird choruses while minimizing memory and battery requirements. A long-term spectrogram has been generated for each audio file to aid in data exploration. The sensor also recorded temperature, minimum- maximum- and mean-sound pressure levels.
Acoustic indices and false colour spectrograms were created for the recordings. Acoustic indices are summaries of the distribution of the acoustic energy in a recording. They are particularly useful for the analysis of long-term recordings of the environment and can be used to identify sound sources of interest, characterise the soundscape, aid in the assessment of fauna biodiversity, monitor temporal trends and track environmental changes. False colour spectrograms are visual representation of individual acoustic indices or combination of multiple indices. They can highlight the presence of specific sound sources, e.g. birds, insects or weather events, providing a tool for navigating long-term recordings.
Data are made available through the data link. For downloading large amount of data, please follow these instructions How to download TERN's acoustic data in bulk
Credit
We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging.
Samford Peri-Urban SuperSite is managed by the Queensland University of Technology.
This work was funded by the Terrestrial Ecosystem Research Network (TERN), an Australian Government National Collaborative Research Infrastructure Strategy (NCRIS) project.
Purpose
Long-term acoustic recordings are collected to characterise the acoustic sources in the ecosystem. Recordings can be used to estimate biodiversity, monitor temporal changes in the soundscape, compare the acoustic characteristics of different locations, and assess the effect of particular events such as bushfires and floods.
Lineage
The first acoustic sensor set up within the site recorded between October 2011 and July 2012. This sensor recorded dual channel MP3 files with a samplig rate of 44,100 Hz. Limited metadata information are available for these recordings.
The second acoustic sensor was set up to collect audio data as part of a continent wide long term monitoring project. The sensor was a Wildlife Acoustics Song Meter 2 equipped with two microphones. According to manufacturer's specifications the microphones sensitivity was -36±4 dB (0 dB=1 V/Pa at 1 kHz). The sensor was mounted on a star picket. Data were recorded for a total of 12 hours per day, split between six hours around dawn and six hours around dusk. Recordings were made as dual channel, three-hour long wac files, and were later converted into flac format. They had a sampling rate of 22,050 or 44,100 Hz and a depth of 16 bits.
Long-term spectrograms have been created for the audio files and are avaialble through the data link.
The Song Meter 2 also recorded 'ancillary data' such as temperature, minimum- maximum- and mean-sound pressure levels.
Acoustic indices were calculated using the software AnalysisProgram version 19.2.2.1. Long term recordings were resampled at 22.05 kHz and divided into one minute long segments. Acoustic indices were calculated for each segment.
Spectral indices were calculated on one minute long spectrograms. Each spectrogram was created by first dividing the one minute long recording into frames of 512 samples each and then calculating the Fast Fourier Transform for each frame. The frequency resolution was 43.1 Hz. The spectra were smoothed using a moving average window of width three and spectral amplitude values are converted into spectral power or decibels (dB).
Summary indices were calculated on the waveform envelope or were derived from the spectrograms. The wave envelope was created by taking the maximum absolute value in each frame. Absolute values were converted to dB.
False colour spectrograms were produced for each spectral index and combination of indices.
Please note the following points:
- dB values are in reference to a hypothetical signal of unit amplitude.
- Before the indices were calculated, noise had been removed form both the waveform and the spectrogram using a modified versions of Lamel's adaptive level equalization (Lamel et al., 1981).
- Entropy values were subtracted from 1 to obtain a measure of energy concentration which provides a more intuitive index.
- To create false colour spectrograms, indices were normalised between a minimum and maximum value. These values affect only the visualization and are provided in the configuration file in the data access link.
- The dataset contains variables labelled DIFsp and SUMsp which are used only for internal checks. They do not correspond to acoustic indices.
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