城市公园春季声景观与植被结构的关系

城市公园是城市生态系统的重要组成部分和城市生物多样性热点地区,具有丰富的声景观资源。由于声景观及声学方法具有信息量大,成本低,低侵入的特点,因此其研究和应用对生态系统健康及监测具有较高价值。声景观研究通过总结生物声的活动或多样性来衡量生物多样性。记录了北京20个城市公园的春季声景观,使用定量方法描述了声景观特征与变化;测试三种了已被证明与生物多样性相关并被广泛使用的声学指数（BIO、ADI、NDSI）与植被群落关系,完成了城市环境中声景观与环境关系的初步探究。研究结果表明：（1）声学指数能够有效表征城市公园声景观信息,具有显著的时间动态特性,能准确反映鸟类黎明合唱等重要生物生态活动;（2）声学强度指数也具有显著的时间动态变化和沿频率梯度的变化,不同的频率区间反映了不同声学群落的活动信息;（3）植被结构尤其是垂直结构对声景观起着重要作用,垂直异质性越大,声学多样性越高。发现支持声景观作为公园植被状况的度量,强调了其作为生物多样性和生态系统健康状况监测方法,用于城市管理和可持续发展的巨大潜力。

Urban parks soundscape and its relationship with vegetation structure: A pilot study

Urban foresters are addressing the challenges of urban biodiversity loss through management plans to adapt to urbanization. Protecting the integrity of the urban ecosystem requires long-term monitoring and planning for resilience as well as effective management. Urban parks are important parts of the urban ecosystem and hot spots of urban biodiversity, with rich soundscape resources. Due to the informative, low-cost, and low-impact features, soundscape-related researches and applications have a great potential of monitoring ecosystem health. Acoustic indices have been commonly used in soundscape ecology researches to measure biodiversity conditions by summarizing the activity or diversity of biological sounds. In this study, we recorded the soundscapes of 20 city parks within Beijing urban area in spring, trying to describe the characteristics and changes of soundscape quantificationally. A total of 23,040 minutes of sound materials were automatically sampled from raw data using Python. Then we calculated three widely used acoustic indices (BIO, ADI, NDSI) that have been proven to be related to biodiversity. The soundscape intensity index, power spectral density (PSD), was calculated to measure acoustic features along every frequency interval. All the indices'' calculation is based on R studio. Spearman rho correlation analysis and principal component analysis were carried out to explore how environmental vegetation structures affecting soundscape in park habitats. The results show that (1) acoustic indices can not only effectively characterize the soundscape information of urban parks, but also have significantly time-dynamic characteristics, which can accurately reflect important biological activities and ecological processes such as bird dawn chorus. (2) The acoustic intensity index also reflects significantly temporal variations and changes along the frequency intervals. Different frequency interval groups reflect the corresponding activity information of acoustic communities. These results also provide more supports to the acoustic niche hypothesis (ANH) theory. (3) Our PCA modelling results show that the vegetation structure, especially the vertical structure, plays an important role in urban soundscapes. More vertical heterogeneity or multilayered vegetation, is associated with more acoustic diversity in urban parks. In the absence of historical soundscape data, we systematically collected and analyzed the soundscape of urban parks in Beijing. This is a pilot study for soundscape in Beijing urban parks. Our findings support soundscape as a measurement of habitat vegetation status and emphasize its great potential for urban management and sustainable development in biodiversity and ecosystem monitoring, which will enable regular assessment of urban parks and forests to inform adaptive planning and management strategies.