Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Glob Chang Biol. 2013 Apr;19(4):1075-84. doi: 10.1111/gcb.12098. Epub 2013 Jan 16.
More humans reside in urban areas than at any other time in history. Protected urban green spaces and transportation greenbelts support many species, but diversity in these areas is generally lower than in undeveloped landscapes. Habitat degradation and fragmentation contribute to lowered diversity and urban homogenization, but less is known about the role of anthropogenic noise. Songbirds are especially vulnerable to anthropogenic noise because they rely on acoustic signals for communication. Recent studies suggest that anthropogenic noise reduces the density and reproductive success of some bird species, but that species which vocalize at frequencies above those of anthropogenic noise are more likely to inhabit noisy areas. We hypothesize that anthropogenic noise is contributing to declines in urban diversity by reducing the abundance of select species in noisy areas, and that species with low-frequency songs are those most likely to be affected. To examine this relationship, we calculated the noise-associated change in overall species richness and in abundance for seven common songbird species. After accounting for variance due to vegetative differences, species richness and the abundance of three of seven species were reduced in noisier locations. Acoustic analysis revealed that minimum song frequency was highly predictive of a species' response to noise, with lower minimum song frequencies incurring greater noise-associated reduction in abundance. These results suggest that anthropogenic noise affects some species independently of vegetative conditions, exacerbating the exclusion of some songbird species in otherwise suitable habitat. Minimum song frequency may provide a useful metric to predict how particular species will be affected by noise. In sum, mitigation of noise may enhance habitat suitability for many songbird species, especially for species with songs that include low-frequency elements.
现在居住在城市中的人类比以往任何时候都多。受保护的城市绿地和交通绿化带为许多物种提供了栖息地，但这些区域的物种多样性通常低于未开发的景观。生境退化和破碎化导致多样性降低和城市同质化，但人们对人为噪声的作用知之甚少。鸣禽特别容易受到人为噪声的影响，因为它们依赖声音信号进行交流。最近的研究表明，人为噪声会降低一些鸟类的密度和繁殖成功率，但那些发出的声音频率高于人为噪声的物种更有可能栖息在嘈杂的区域。我们假设人为噪声通过减少嘈杂区域中某些物种的数量，从而导致城市多样性下降，而低频歌曲的物种最有可能受到影响。为了检验这种关系，我们计算了七种常见鸣禽的总物种丰富度和数量与噪声相关的变化。在考虑了植被差异引起的方差后，七种物种中的三种在噪声较大的地方的物种丰富度和数量减少。声学分析显示，最小鸣叫声频率高度预测了物种对噪声的反应，最小鸣叫声频率越低，受噪声影响的数量减少越大。这些结果表明，人为噪声会独立于植被条件影响某些物种，从而加剧了一些鸣禽物种在其他适宜栖息地中的排斥。最小鸣叫声频率可能是一种有用的指标，可以预测特定物种将如何受到噪声的影响。总之，噪声的缓解可能会提高许多鸣禽物种的栖息地适宜性，尤其是对那些包含低频元素的鸣叫声的物种。
