Data from: The soundscapes of lakes across an urbanization gradient

Background/Methodology: A significant implication of increasing urbanization is anthropogenic noise pollution. Although noise is strongly associated with disruption of animal communication systems and negative health effects for humans, the study of these consequences at ecologically relevant spatial and temporal scales (termed ‘soundscape ecology’) is in early stages of application. In this study, we examined the above- and below-water soundscape of recreational and residential lakes in the region surrounding a large metropolitan area. Using univariate and multivariate approaches we test the importance of large- and local-scale landscape factors in driving acoustic characteristics across an urbanization gradient, and visualize changes in the soundscape over space and time. Principal Findings: Anthropogenic noise (‘anthrophony’) was strongly predicted by a landcover-based metric of urbanization (within a 10 km radius of the lake), with presence of a public park as a secondary influence; this urbanization signal was apparent even in below-water recordings. The percent of hourly measurements exceeding noise thresholds associated with outdoor disturbance was 67%, 17%, and 0%, respectively, for lakes characterized as High, Medium, and Low urbanization. Decreased biophony (proportion of natural sounds) was associated with presence of a public park followed by increased urbanization; time of day was also a significant predictor of biophony. Local-scale (shoreline) residential development was not related to changes in biophony. The patterns we identify are illustrated with a multivariate approach which allows use of entire sound samples and facilitates interpretation of changes in a soundscape. Conclusions/Significance: As highly valued residential and recreation areas, lakes represent ‘everyday soundscapes’ important to both humans and wildlife. Our findings that many of these areas, particularly those with public parks, routinely experience sound types and levels associated with disturbance, suggests that urban planners need to account for the effect of increasing development on soundscapes to avoid compromising goals for ecological and human health.

研究背景与方法论：城市化进程加剧带来的一项重要影响是人为噪声污染。尽管噪声与动物通讯系统干扰及人类健康负面影响存在显著关联，但在生态学相关的时空尺度下开展此类影响研究（即“声景生态学（soundscape ecology）”）仍处于早期应用阶段。本研究针对大型都市区周边区域的休闲与居住型湖泊，对其水上及水下声景展开调查。研究采用单变量与多变量分析方法，探究大尺度与局地尺度景观因子在驱动城市化梯度下声学特征变化中的作用，并可视化声景随空间与时间的演变规律。
主要研究结果：人为声（anthrophony）的强度可通过基于湖泊周边10 km半径范围内的城市化土地覆盖指标进行有效预测，公共公园的存在为次要影响因子；该城市化信号甚至在水下录音中也可被观测到。在被划分为高、中、低城市化水平的湖泊中，每小时测量值超过户外干扰相关噪声阈值的比例分别为67%、17%和0%。生物声（biophony，即自然声音占比）的下降与公共公园的存在相关，随后随城市化水平升高而进一步降低；时段同样是生物声的显著预测因子。局地尺度（湖岸线）的住宅开发与生物声变化无显著关联。本研究采用的多变量分析方法可完整利用全部声景样本，便于阐释声景的变化特征，文中以此方法对观测到的规律进行了可视化展示。
结论与意义：作为兼具高价值居住与休闲功能的区域，湖泊是对人类与野生动物均至关重要的“日常声景”。本研究发现，诸多此类区域（尤其是配备公共公园的区域）经常出现与干扰相关的声音类型与声级，这表明城市规划者需要考量开发强度增加对声景的影响，以避免损害生态与人类健康的相关目标。