Using soundscape diversity to interpret soundscape evaluation in urban green spaces-Relationship, integration, and application

Improving the evaluation criteria for the soundscape of urban green spaces is essential for the purposes of designing and planning. Nevertheless, studies that focus on the significance of soundscape diversity in such evaluations have been very limited. Furthermore, the relationship between soundscape diversity and the indicators used to evaluate soundscape in urban green spaces remains unclear. The present study investigates the relationship by conducting a soundscape survey across 30 green spaces to derive four soundscape diversity indices: the soundscape diversity index (SDI), soundscape richness index (SRI), soundscape dominance index (SDO), and soundscape evenness index (SEI). The findings indicate that soundscape diversity significantly influence sound preference, perceived affective quality, and the overall soundscape assessment, especially in traffic-noise-dominated and natural-sounds-dominated green spaces. Additionally, sound preference and perceived affective quality were found to act as intermediary factors between soundscape diversity and the overall soundscape assessment. The mediating effect was responsible for 23.7%, 24.5%, and 84.3% of the total effect in three types of green space, respectively. Therefore, the ideal soundscape diversity in urban green spaces depends on their specific type, rather than a simple "more is better" or "less is better" approach. Correspondingly, the use of soundscape diversity as a novel evaluation indicator can be employed for the assessment and design of soundscape in urban green spaces in future studies.