Soundscape mapping for spatial-temporal estimate on bird activities in urban forests

Through the following three-dimensional space graphical representation, we show that the urban forest spatial structure is the most critical factor affecting the biophonic activities of bird communities, which is the most important finding in this research. [Display omitted] •The soundscape mapping method can be used to explore the relationship between the birds and urban forests.•Bird communities with different vocal frequency bands had different forest environmental preferences.•Tourist accessibility at the recording points had a significant impact on bird activities.•Urban forest spatial structure was the factor that affects bird activities the most. Soundscape mapping provides a unique perspective to explain the complicated spatial-temporal change of bird activities in urban forests. Most studies of soundscapes have used multi-point distribution to record sounds, which is challenging for explaining complex interferences factors in urban areas. In this study, we used soundscape mapping to explore the habitat selection of bird communities in the context of spatial-temporal structural changes. We selected the transition area from city to forest in Shenzhen, China, as the study area, set up 30 recording points which arranged in grid patterns (5 × 6), and used synchronic recording methodology to collect sounds. Aural species identification, power spectral density (PSD), and normalized-difference sound index (NDSI) were used to quantify sounds. Passerine birds (92.11 %) were found to comprise the first acoustic communities. Changes in bird species populations among seasons were noted, with spring having the most abundant bird species number (n = 59) and the most abundant ecoacoustic events. Bird communities with different frequency band clusters having different preferences for vegetation characteristics were detected. A significant two-way interaction between the accessibility of recording points and seasons on bird activities was found in this study. Urban forest spatial structure had a great effect on bird activities, and specifically through the shape of forest vertical structure complexity and forest edge effect. Our study shows the broader application potential of soundscape mapping in urban forest ecosystem research.