Abstract:

Objective: In this study, we investigated the characteristics and influencing factors of birds' and insects' sound in forests to understand the activity and spatio-temporal pattern of vocal communities in urban forest background.This study aims to further understand important landscape resources in urban forests and provide new ideas for the investigation and conservation of biodiversity. Method: Based on the biophony at 3 urban forest sites (foothills, river valleys and ridges) in the Yuanshan Park in spring, the sound signals quantified by species identification, frequency analysis, spectrum analysis and Acoustic Complexity Index (ACI).The environmental factors(vegetation composition, vertical structure, illumination, temperature, relative humidity, wind speed), were analyzed to identify the activity rule and mechanism of the vocal community. Result: The results showed that the spring forest soundscape in Shenzhen was composed of 3 kinds of sound, namely, the sound of birds, the sound of insects and the mixed sound of birds and insects. The dominant vocal communities were Red-billed Leiothrix (Leiothrix lutea), Light-vented Bulbul (Pycnonotus sinensis), Red-whiskered Bulbul (Pycnonotus jocosus), Common Tailorbird (Orthotomus sutorius), Malaysian Hawk-Cuckoo (Cuculus fugax) and Chestnut Bulbul (Hemixos castanonotus). Sounding community of insects was composed of Cicadas (Cicadidae), Crickets (Gryllidae) and Tettigoniidae. In terms of temporal change, the sound of birds in the sunrise and sunset period was dominant; the sound of birds disappears in night, while the sound of the insects became dominant. The rest of day was the mixture sounds of birds and insects. In addition, the relationship of forest soundscape with characteristics of vegetation communities (diversity, evenness, dominance, vertical structure and phenology) and meteorological factors were analyzed. The results showed that the spatial structure of the vegetation, the phenology of the shrub layer and the intensity of illumination had great influence on the bird's and insect's vocal activities in spring. The birds' and insects' vocal activities were the most abundant in the ridge where the vertical structure of vegetation was simple, and the phenology of shrub layer was obvious. Conclusion: The spring soundscape of Shenzhen is characterized by different sound elements at different time periods, showing abundant variation characteristics and obvious regularity. At the same time, the characteristics of the vegetation community and the meteorological factors have a significant influence on the vocal community. Through the study onthe characteristics of the soundscape and its influencing factors we can fully understand the forest landscape, provide data and theoretical support for the protection and utilization of forest landscape resources, and enable the citizens to enjoy the green welfare.

Key words: soundscape, urban forestry, spatio-temporal variation, birds call, insects sounds