Soundscape diversity: Evaluation indices of the sound environment in urban green spaces – Effectiveness, role, and interpretation

Urban green space sound sources play an important role in providing people with high quality recreation experiences. However, the evaluation index for urban green space sound sources is still limited. The main purpose of this study is to propose indices for soundscape diversity in urban green spaces, compare soundscape diversity with acoustic diversity, and understand the role of soundscape diversity in urban green spaces. In our field investigation, the sound sources of 30 sample sites were recorded over a five-minute period, and the soundscape diversity index (SDI), soundscape richness index (SRI), soundscape dominance index (SDO), and soundscape evenness index (SEI) were calculated. The results showed that soundscape diversity indices are more suitable for the evaluation of urban green space sound diversity than acoustic diversity indices. There is a significant correlation between soundscape diversity and urban green space landscape patterns, and there is a varied relationship between soundscape diversity and sound perception in different urban green spaces. Soundscape diversity can be explained by existing objective acoustic indicators, which can explain 55% of SDI model variations, 71% of SRI model variations, 43% of SDO model variations, and 32% of SEI model variations. Soundscape diversity can be applied to future urban green space planning and acoustic environment design.