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Author (up) Dominoni, D.M.; Helm, B.; Lehmann, M.; Dowse, H.B.; Partecke, J. url  doi
openurl 
  Title Clocks for the city: circadian differences between forest and city songbirds Type Journal Article
  Year 2013 Publication Proceedings. Biological Sciences / The Royal Society Abbreviated Journal Proc Biol Sci  
  Volume 280 Issue 1763 Pages 20130593  
  Keywords Animals; Circadian Clocks/*physiology; Circadian Rhythm; Cities; *Ecosystem; Light; Male; Songbirds/classification/*physiology; Trees; Urbanization; birds; chronotype; circadian rhythms; light at night; radio-telemetry; urbanization  
  Abstract To keep pace with progressing urbanization organisms must cope with extensive habitat change. Anthropogenic light and noise have modified differences between day and night, and may thereby interfere with circadian clocks. Urbanized species, such as birds, are known to advance their activity to early morning and night hours. We hypothesized that such modified activity patterns are reflected by properties of the endogenous circadian clock. Using automatic radio-telemetry, we tested this idea by comparing activity patterns of free-living forest and city European blackbirds (Turdus merula). We then recaptured the same individuals and recorded their activity under constant conditions. City birds started their activity earlier and had faster but less robust circadian oscillation of locomotor activity than forest conspecifics. Circadian period length predicted start of activity in the field, and this relationship was mainly explained by fast-paced and early-rising city birds. Although based on only two populations, our findings point to links between city life, chronotype and circadian phenotype in songbirds, and potentially in other organisms that colonize urban habitats, and highlight that urban environments can significantly modify biologically important rhythms in wild organisms.  
  Address Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell 78479, Germany. ddominoni@orn.mpg.de  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0962-8452 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23740778; PMCID:PMC3774226 Approved no  
  Call Number IDA @ john @ Serial 42  
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Author (up) Gerrish, G.A.; Morin, J.G.; Rivers, T.J.; Patrawala, Z. url  doi
openurl 
  Title Darkness as an ecological resource: the role of light in partitioning the nocturnal niche Type Journal Article
  Year 2009 Publication Oecologia Abbreviated Journal Oecologia  
  Volume 160 Issue 3 Pages 525-536  
  Keywords Age Factors; Animals; Belize; Crustacea/*physiology; *Darkness; *Ecosystem; Feeding Behavior/physiology; Linear Models; Motor Activity/*physiology; Photoperiod; Sexual Behavior, Animal/physiology; Water Movements  
  Abstract Nocturnal behaviors that vary as a function of light intensity, either from the setting sun or the moon, are typically labeled as circadian or circalunar. Both of these terms refer to endogenous time-dependent behaviors. In contrast, the nightly reproductive and feeding behaviors of Vargula annecohenae, a bioluminescent ostracod (Arthropoda: Crustacea) fluctuate in response to light intensity, an exogenous factor that is not strictly time-dependent. We measured adult and juvenile activity of V. annecohenae throughout lunar cycles in January/February and June 2003. Overnight and nightly measurements of foraging and reproductive behavior of adult V. annecohenae indicated that activity was greatest when a critical “dark threshold” was reached and that the dark threshold for adult V. annecohenae is met when less than a third of the moon is visible or at the intensity of light 2-3 min before the start of nautical twilight when no moon is illuminated. Juvenile V. annecohenae were also nocturnally active but demonstrated little or no response to lunar illumination, remaining active even during brightly moonlit periods. In addition to light level, water velocity also influenced the behaviors of V. annecohenae, with fewer juveniles and adults actively foraging on nights when water velocity was high (>25 cm/s). Our data demonstrate that the strongest environmental factor influencing adult feeding and reproductive behaviors of V. annecohenae is the availability of time when illumination is below the critical dark threshold. This dependence on darkness for successful growth and reproduction allows us to classify darkness as a resource, in the same way that the term has been applied to time, space and temperature.  
  Address Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14850, USA. ggerrish@nd.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0029-8549 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19330516 Approved no  
  Call Number IDA @ john @ Serial 16  
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Author (up) Kyba, C.C.M.; Ruhtz, T.; Fischer, J.; Hölker, F. url  doi
openurl 
  Title Cloud coverage acts as an amplifier for ecological light pollution in urban ecosystems Type Journal Article
  Year 2011 Publication PloS one Abbreviated Journal PLoS One  
  Volume 6 Issue 3 Pages e17307  
  Keywords Berlin; *Cities; *Ecosystem; Environmental Pollution/*adverse effects/analysis; *Light; Seasons; *Weather  
  Abstract The diurnal cycle of light and dark is one of the strongest environmental factors for life on Earth. Many species in both terrestrial and aquatic ecosystems use the level of ambient light to regulate their metabolism, growth, and behavior. The sky glow caused by artificial lighting from urban areas disrupts this natural cycle, and has been shown to impact the behavior of organisms, even many kilometers away from the light sources. It could be hypothesized that factors that increase the luminance of the sky amplify the degree of this “ecological light pollution”. We show that cloud coverage dramatically amplifies the sky luminance, by a factor of 10.1 for one location inside of Berlin and by a factor of 2.8 at 32 km from the city center. We also show that inside of the city overcast nights are brighter than clear rural moonlit nights, by a factor of 4.1. These results have important implications for choronobiological and chronoecological studies in urban areas, where this amplification effect has previously not been considered.  
  Address Institute for Space Sciences, Freie Universitat Berlin, Berlin, Germany. christopher.kyba@wew.fu-berlin.de  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21399694; PMCID:PMC3047560 Approved no  
  Call Number IDA @ john @ Serial 20  
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