Duarte M H L, Kaizer M C, Young R J, Rodrigues M, Sousa-Lima R S
Conservation, Ecology and Animal Behaviour Group-Laboratory of Bioacoustics, Post-Graduate Program in Vertebrate Biology and Museum of Natural Sciences, Pontifical Catholic University of Minas Gerais, Avenida Dom José Gaspar, 290, Bairro Coração Eucarístico, Belo Horizonte, Minas Gerais, 30535-901, Brazil.
Laboratory of Ornithology, Department of Zoology, Federal University of Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Bairro Pampulha, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Primates. 2018 Jan;59(1):89-97. doi: 10.1007/s10329-017-0629-4. Epub 2017 Sep 11.
Anthropogenic noise pollution is increasing and can constrain acoustic communication in animals. Our aim was to investigate if the acoustic parameters of loud calls and their diurnal pattern in the black-fronted titi monkey (Callicebus nigrifrons) are affected by noise produced by mining activity in a fragment of Atlantic Forest in Brazil. We installed two passive acoustic monitoring devices to record sound 24 h/day, 7 days every 2 months, for a year; one unit was close to an opencast mine and the other 2.5 km away from it. Both sites presented similar habitat structures and were inhabited by groups of black-fronted titi monkeys. We quantified the noise at both sites by measuring the equivalent continuous sound level every 2 months for 1 year and quantified the emission of loud calls by titi monkeys through visual inspection of the recordings. The close site presented higher ambient noise levels than the far site. The quantitative comparison of loud calls of black-fronted titi monkeys between the two sites showed less calling activity in the site close to the mine than in the site further away. Approximately 20 % of the calls detected at the site close to the mine were masked by noise from truck traffic. Loud calls were longer at the site far from the mine and the diurnal patterns of vocal activity differed in the amount of calling as well as in the timing of peak calling activity between the two sites. Our results indicate that mining noise may constrain titi monkeys' long-distance vocal communication. Loud calls occupy a similar frequency band to mining noise, and an increase in ambient noise may be triggering black-fronted titi monkeys to adjust their long-distance communication patterns to avoid masking of their calls. Given that vocalizations are an important means of social interaction in this species, there are concerns about the impact of mining noise on populations exposed to this human activity.
人为噪声污染正在加剧，可能会限制动物的声学交流。我们的目的是调查巴西大西洋森林一片区域内的采矿活动所产生的噪声是否会影响黑额伶猴（Callicebus nigrifrons）大声呼叫的声学参数及其昼夜模式。我们安装了两个被动声学监测设备，一年中每两个月的7天里每天24小时记录声音；一个设备靠近露天矿，另一个距离露天矿2.5公里。两个地点的栖息地结构相似，都有黑额伶猴群体居住。我们通过在一年时间里每两个月测量一次等效连续声级来量化两个地点的噪声，并通过目视检查录音来量化伶猴大声呼叫的发声情况。靠近矿场的地点环境噪声水平高于较远的地点。对两个地点的黑额伶猴大声呼叫进行定量比较发现，靠近矿场的地点的呼叫活动比远处的地点少。在靠近矿场的地点检测到的大约20%的呼叫被卡车交通产生的噪声掩盖。远离矿场的地点的大声呼叫持续时间更长，而且两个地点的发声活动昼夜模式在呼叫量以及呼叫活动高峰时间方面都有所不同。我们的结果表明，采矿噪声可能会限制伶猴的远距离声学交流。大声呼叫所占据的频段与采矿噪声相似，环境噪声的增加可能促使黑额伶猴调整其远距离交流模式，以避免叫声被掩盖。鉴于发声是该物种社会互动的重要方式，人们担心采矿噪声对接触这种人类活动的种群的影响。
