Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest

Long-term biological and phenological monitoring has become essential for conservation in the face of rapid climate change. In this study, we utilized long-term passive acoustic recording data. We employed a combination of 14 features extracted from acoustic indices and unsupervised clustering metho...

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Main Authors: Yan-Tin Lai, Sheng-Shan Lu, Ming-Tang Shiao
Format: Article
Language:English
Published: Elsevier 2025-02-01
Series:Ecological Indicators
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Online Access:http://www.sciencedirect.com/science/article/pii/S1470160X2500055X
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author Yan-Tin Lai
Sheng-Shan Lu
Ming-Tang Shiao
author_facet Yan-Tin Lai
Sheng-Shan Lu
Ming-Tang Shiao
author_sort Yan-Tin Lai
collection DOAJ
description Long-term biological and phenological monitoring has become essential for conservation in the face of rapid climate change. In this study, we utilized long-term passive acoustic recording data. We employed a combination of 14 features extracted from acoustic indices and unsupervised clustering methods to classify the soundscapes of Taiwan’s subtropical rainforests. Our results demonstrated that in environments with complex soundscapes, this approach effectively distinguished predominant acoustic elements, including cicadas, orthopterans, rain, and frogs, constituting more than 10–20% of the total audio recordings, and identified smaller yet significant groups, such as avian dawn choruses, accounting for approximately 2% of the recordings. The clustering results enabled the description of dynamic changes in the soundscape throughout the year. In the subtropical rainforest, rain and wind affected the soundscape from October to March, whereas bird songs were prominent only in the early mornings from February to May, which were subsequently replaced by cicada calls that continued until late August. The nocturnal soundscape was dominated by frog calls and orthopteran stridulations in the aquatic and forest habitats. Correlations among the vocal activities of several representative groups, temperature, and rainfall were found. Our study confirms that acoustic indices can extract meaningful ecological features, and unsupervised algorithms offer valuable insights into biodiversity exploration data-scarce regions. The combination of these methods has led to the development of non-species-specific soundscape classification, which not only facilitates the monitoring of phenological dynamics across multiple biological groups in the face of climate change but also lays the foundation for further exploration of key taxa.
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spelling doaj-art-cf54d78ca81a47a681a3c6780d60dc752025-01-29T05:00:21ZengElsevierEcological Indicators1470-160X2025-02-01171113126Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforestYan-Tin Lai0Sheng-Shan Lu1Ming-Tang Shiao2Forest Protection Division, Taiwan Forestry Research Institute, 53 Nanhai Rd., Zhongzheng Dist., Taipei 100051 TaiwanForest Protection Division, Taiwan Forestry Research Institute, 53 Nanhai Rd., Zhongzheng Dist., Taipei 100051 TaiwanCorresponding author.; Forest Protection Division, Taiwan Forestry Research Institute, 53 Nanhai Rd., Zhongzheng Dist., Taipei 100051 TaiwanLong-term biological and phenological monitoring has become essential for conservation in the face of rapid climate change. In this study, we utilized long-term passive acoustic recording data. We employed a combination of 14 features extracted from acoustic indices and unsupervised clustering methods to classify the soundscapes of Taiwan’s subtropical rainforests. Our results demonstrated that in environments with complex soundscapes, this approach effectively distinguished predominant acoustic elements, including cicadas, orthopterans, rain, and frogs, constituting more than 10–20% of the total audio recordings, and identified smaller yet significant groups, such as avian dawn choruses, accounting for approximately 2% of the recordings. The clustering results enabled the description of dynamic changes in the soundscape throughout the year. In the subtropical rainforest, rain and wind affected the soundscape from October to March, whereas bird songs were prominent only in the early mornings from February to May, which were subsequently replaced by cicada calls that continued until late August. The nocturnal soundscape was dominated by frog calls and orthopteran stridulations in the aquatic and forest habitats. Correlations among the vocal activities of several representative groups, temperature, and rainfall were found. Our study confirms that acoustic indices can extract meaningful ecological features, and unsupervised algorithms offer valuable insights into biodiversity exploration data-scarce regions. The combination of these methods has led to the development of non-species-specific soundscape classification, which not only facilitates the monitoring of phenological dynamics across multiple biological groups in the face of climate change but also lays the foundation for further exploration of key taxa.http://www.sciencedirect.com/science/article/pii/S1470160X2500055XPassive acoustic monitoringAcoustic scenesUnsupervised learningVocal phenology
spellingShingle Yan-Tin Lai
Sheng-Shan Lu
Ming-Tang Shiao
Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest
Ecological Indicators
Passive acoustic monitoring
Acoustic scenes
Unsupervised learning
Vocal phenology
title Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest
title_full Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest
title_fullStr Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest
title_full_unstemmed Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest
title_short Characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest
title_sort characterization of soundscapes with acoustic indices and clustering reveals phenology patterns in a subtropical rainforest
topic Passive acoustic monitoring
Acoustic scenes
Unsupervised learning
Vocal phenology
url http://www.sciencedirect.com/science/article/pii/S1470160X2500055X
work_keys_str_mv AT yantinlai characterizationofsoundscapeswithacousticindicesandclusteringrevealsphenologypatternsinasubtropicalrainforest
AT shengshanlu characterizationofsoundscapeswithacousticindicesandclusteringrevealsphenologypatternsinasubtropicalrainforest
AT mingtangshiao characterizationofsoundscapeswithacousticindicesandclusteringrevealsphenologypatternsinasubtropicalrainforest