Island biogeography of soundscapes: Island area shapes spatial patterns of avian acoustic diversity

• Published in: Journal of Biogeography
• Main Authors: Han, Peng, Zhao, Yuhao, Kang, Yi, Ding, Ping, Si, Xingfeng
• Other Authors: National Natural Science Foundation of China, Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2022
• Subjects: Ecology; Ecology, Evolution, Behavior and Systematics; Close Islands
• Online Access: http://dx.doi.org/10.1111/jbi.14551; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jbi.14551; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jbi.14551

Abstract Aim The equilibrium theory of island biogeography predicts the positive species–area relationship and the negative species–isolation relationship, resulting in higher species richness on large and close islands. Unlike species richness, soundscape diversity integrates sound from various sources (e.g. biophony, geophony and anthrophony). However, how soundscape diversity varies with island area and isolation still needs to be tested. Here, we explored the island biogeography of bird soundscapes and the determinants of island attributes in shaping bird diversity and soundscape diversity. Location Thousand Island Lake, Zhejiang, China. Taxon Birds. Methods We recorded avian soundscapes by audio recorders and censused bird diversity by line transects on 20 land‐bridge islands. We calculated four acoustic indices (acoustic complexity index, bioacoustic index, acoustic evenness index and acoustic entropy index) to assess acoustic richness, evenness and heterogeneity to explore the soundscape diversity of birds. We used multiple linear regressions, spatial autoregressions and piecewise structural equation models to examine the relationships between bird richness and acoustic diversity, and island attributes. Results We found positive diversity–area relationships for avian soundscapes. Larger islands had more vocal species and higher habitat diversity, which led to an increment in the richness and unevenness of avian soundscapes on large islands. Acoustic evenness decreased with increasing isolation (distance to the mainland). Main Conclusions Soundscapes on large islands are more diverse than those on small islands. Rich acoustic assemblages and heterogeneous habitats promote increased soundscape diversity on islands. Conversely, the lack of vocal contributors, resulting in a decrement in the communication of acoustic signals, can create a lower soundscape diversity on small and remote islands. Our study emphasizes the necessity of examining both species and habitat diversity in island biogeography for better ...