Biodiv Sci ›› 2023, Vol. 31 ›› Issue (1): 22080.  DOI: 10.17520/biods.2022080

• Original Papers: Animal Diversity •     Next Articles

Exploring the application of acoustic indices in the assessment of bird diversity in urban forests

Qi Bian1,2, Cheng Wang1,2,*(), He Cheng1,2,3, Dan Han1,2, Yilin Zhao1,2, Luqin Yin1,2   

  1. 1. Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091
    2. Urban Forest Research Center, National Forestry and Grassland Administration, Beijing 100091
    3. Turenscape Company Limited, Beijing 100080
  • Received:2022-02-18 Accepted:2022-06-01 Online:2023-01-20 Published:2022-06-23
  • Contact: Cheng Wang


Aims: Calling is an important way for birds to communicate and transmit information to each other. This provides a unique opportunity to assess bird diversity through acoustic monitoring. The use of acoustic indices for the rapid assessment of biodiversity is an emerging survey method, but the complex sonic environment in urban forests may lead to bias. The feasibility of using acoustic indices to assess bird diversity in urban forests still needs to be further explored.

Methods: To understand the effectiveness of acoustic indices in urban forests, we set up 50 matrix survey sample sites in Beijing Eastern Suburb Forest Park. Bird sample point observations and simultaneous acoustic data collection were conducted monthly from April to June 2021. In order to verify the effectiveness of acoustic monitoring, we compared the results of the two methods. Spearman correlation analysis and generalized linear mixed models were used to assess the relationship between six commonly used acoustic indices and bird richness and abundance. The performance of each acoustic index was subsequently measured.

Results: (1) A total of 35 species, comprising 10 orders and 23 families, were recorded in this experiment. Although the total number of species identified through acoustic monitoring was equal to bird observations, there were discrepancies between which specific bird species were observed. (2) The correlation between acoustic indices and bird richness and abundance varied significantly in different months. The acoustic complexity index (ACI) and normalized difference sound index (NDSI) outperformed others were key variables for assessing bird diversity. (3) Acoustic indices had higher predictive power for bird abundance (R2m = 0.32, R2c = 0.80) than richness (R2m = 0.12, R2c = 0.18).

Conclusion: Acoustic monitoring provides a promising tool for urban biodiversity assessment, but there are still many areas that need to be explored. With the gradual improvement of methods and technology, acoustic monitoring has great potential in the tracking and conservation management of urban biodiversity.

Key words: urban forest, bird diversity, acoustic indices, acoustic monitoring