![]() ![]() Anthropogenic noise interferes with the spread of acoustic information and, thus, is associated with a variety of fitness and behavioural consequences. Moreover, anthropogenic noise and artificial night lighting are two major challenges closely linked to urbanization.Īlthough ambient noise is ubiquitous in many habitats, in terms of leaf-rustling, waterfalls or animal sounds, anthropogenic noise is novel by its high amplitude, low frequency, and diurnal periodicity. These are, amongst others, higher temperatures than in the surrounding, chemical contaminants, modified habitat structure including sealed pavement, concrete buildings, and exotic vegetation. With regard to flora and fauna, cities constitute a novel environment where organisms are exposed to other ecological conditions than their rural conspecifics. In the foreseeable future, humans will become increasingly urban and cities will further increase in both extent and inhabitants as population growth is expected to concentrate in urban settlements. At the end of the 20 th century less than 3% of the Earth’s terrestrial surface was covered by human settlements, but the impacts were rather global as they consume 60% of residential water, 76% of industrial used wood, and contribute 78% to carbon emissions. The conversion of natural landscapes to built-up area is one of the tremendous changes humans caused in the last three centuries. Mankind has altered Earth towards its requirements to an extent which caused Crutzen to rename the last three centuries the ‘Anthropocene’ – the human-dominated, geological epoch. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: The project was funded by the Federal Ministry of Education and Research (BMBF,, FKZ: 033L038E), additional financial support was provided by Helmholtz Impulse and Networking Fund through Helmholtz Interdisciplinary Graduate School for Environmental Research ( ). ![]() Received: FebruAccepted: JPublished: August 7, 2013Ĭopyright: © 2013 Nordt, Klenke. PLoS ONE 8(8):Įditor: Nicola Saino, University of Milan, Italy These findings indicate that urban hazards such as ambient noise and light pollution show a manifold interference with naturally evolved cycles and have significant effects on the activity patterns of urban blackbirds.Ĭitation: Nordt A, Klenke R (2013) Sleepless in Town – Drivers of the Temporal Shift in Dawn Song in Urban European Blackbirds. Beside these temporal effects, we also found differences in the spatial autocorrelation of dawn song onset showing a much higher variability in noisy city areas than in rural parks and forests. Cloudy and cold weather delayed the onset, but cloud cover was assumed to reflect night light emissions, thus, amplified sky luminance and increased the effect of artificial night light. We additionally included meteorological conditions into the analysis and found an effect on the song onset. We found traffic noise to be the driving factor of the shift of dawn song into true night, although it was not completely separable from the effects of ambient night light. In the city centre, blackbirds started their dawn song up to 5 hours earlier compared to those in semi-natural habitats. This gradient of anthropogenic noise and artificial night light was reflected in the timing of dawn song. We investigated the onset of blackbird dawn song along a steep urban gradient ranging from an urban forest to the city centre of Leipzig, Germany. Our aim was to clarify the specific contributions of artificial night light and traffic noise on the timing of dawn song of urban European Blackbirds ( Turdus merula). time their dawn song according to changing light intensities. ![]() Songbirds are particularly affected by these factors, because they rely on the spread of acoustic information and adjust their behaviour to the rhythm of night and day, e.g. Especially anthropogenic noise and artificial night light are closely linked to urbanization and pose new challenges to urban species. Organisms living in urban environments are exposed to different environmental conditions compared to their rural conspecifics. ![]()
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