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Author Dominoni, D.M.; Partecke, J. url  doi
openurl 
  Title Does light pollution alter daylength? A test using light loggers on free-ranging European blackbirds (Turdus merula) Type Journal Article
  Year 2015 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci  
  Volume 370 Issue Pages 20140118  
  Keywords Animals; urbanization; light pollution; artificial light at night; light loggers; daylength; photoperiod; Turdus merula; European blackbird  
  Abstract Artificial light at night is one of the most apparent environmental changes accompanying anthropogenic habitat change. The global increase in light pollution poses new challenges to wild species, but we still have limited understanding of the temporal and spatial pattern of exposure to light at night. In particular, it has been suggested by several studies that animals exposed to light pollution, such as songbirds, perceive a longer daylength compared with conspecifics living in natural darker areas, but direct tests of such a hypothesis are still lacking. Here, we use a combination of light loggers deployed on individual European blackbirds, as well as automated radiotelemetry,to examine whether urban birds are exposed to a longer daylength than forest counterparts. We first used activity data from forest birds to determine the level of light intensity which defines the onset and offset of daily activity in rural areas. We then used this value as threshold to calculate the subjective perceived daylength of both forest and urban blackbirds. In March, when reproductive growth occurs, urban birds were exposed on average to a 49-min longer subjective perceived daylength than forest ones, which corresponds to a 19-day difference in photoperiod at this time of the year. In the field, urban blackbirds reached reproductive maturity 19 day earlier than rural birds, suggesting that light pollution could be responsible of most of the variation in reproductive timing found between urban and rural dwellers. We conclude that light at night is the most relevant change in ambient light affecting biological rhythms in avian urban-dwellers, most likely via a modification of the perceived photoperiod.  
  Address Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK; davide.dominoni@glasgow.ac.uk  
  Corporate Author Thesis  
  Publisher Royal Society Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title The biological impacts of artificial light at night: from molecules to communities Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 1117  
Permanent link to this record
 

 
Author Dominoni, D.M.; Goymann, W.; Helm, B.; Partecke, J. url  doi
openurl 
  Title Urban-like night illumination reduces melatonin release in European blackbirds (Turdus merula): implications of city life for biological time-keeping of songbirds Type Journal Article
  Year 2013 Publication Frontiers in Zoology Abbreviated Journal Front Zool  
  Volume 10 Issue 1 Pages 60  
  Keywords European blackbirds; birds; Turdus merula; animals; melatonin; *Photoperiod  
  Abstract INTRODUCTION: Artificial light-at-night is known to affect a broad array of behaviours and physiological processes. In urbanized bird species, light-at-night advances important biological rhythms such as daily cycles of activity/rest and timing of reproduction, but our knowledge of the underlying physiological mechanisms is limited. Given its role as chronobiological signal, melatonin is a strong candidate for mediating the effects of light-at-night. RESULTS: We exposed urban and rural European blackbirds (Turdus merula) to two light treatments equal in photoperiod but with different light intensities at night. The control group was exposed to 0.0001 lux (almost darkness), while the experimental group was exposed to 0.3 lux at night, simulating conditions recorded previously on free-living urban blackbirds. We obtained diel profiles of plasma melatonin for all birds in summer (July) and winter (January), while simultaneously recording locomotor activity. Daily patterns of melatonin concentrations were clearly affected by light-at-night in both seasons. In winter, melatonin concentrations of light-at-night birds were lower in the early and late night than in those of birds kept in darkness. In summer, melatonin concentrations of the light-at-night birds were lower through all night compared to birds kept in darkness. Locomotor activity in light-at-night birds was overall higher than in control individuals, both during the day and at night, and it increased sharply before dawn. In winter, the amount of activity before dawn in the light-at-night group correlated with changes in melatonin from midnight to late night: the greater the decrease in melatonin, the greater the amount of pre-dawn activity. Urban and rural birds responded similarly to light-at-night with respect to melatonin, but differed in their behaviour, with rural birds showing more locomotor activity than urban counterparts. CONCLUSIONS: This study points to reduced melatonin release at night as a potential physiological mechanism underlying the advanced onset of morning activity of urbanized birds. Based on the pattern of melatonin secretion, we suggest that birds responded to light-at-night as if they were exposed to a longer day than birds kept under dark nights.  
  Address Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany. ddominoni@orn.mpg.de  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1742-9994 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24090446; PMCID:PMC3850952 Approved no  
  Call Number IDA @ john @ Serial 41  
Permanent link to this record
 

 
Author Dominoni, D.M.; Quetting, M.; Partecke, J. url  doi
openurl 
  Title Long-term effects of chronic light pollution on seasonal functions of European blackbirds (Turdus merula) Type Journal Article
  Year 2013 Publication PloS one Abbreviated Journal PLoS One  
  Volume 8 Issue 12 Pages e85069  
  Keywords Turdus merula; European blackbird; birds; animals; Reproduction  
  Abstract Light pollution is known to affect important biological functions of wild animals, including daily and annual cycles. However, knowledge about long-term effects of chronic exposure to artificial light at night is still very limited. Here we present data on reproductive physiology, molt and locomotor activity during two-year cycles of European blackbirds (Turdus merula) exposed to either dark nights or 0.3 lux at night. As expected, control birds kept under dark nights exhibited two regular testicular and testosterone cycles during the two-year experiment. Control urban birds developed testes faster than their control rural conspecifics. Conversely, while in the first year blackbirds exposed to light at night showed a normal but earlier gonadal cycle compared to control birds, during the second year the reproductive system did not develop at all: both testicular size and testosterone concentration were at baseline levels in all birds. In addition, molt sequence in light-treated birds was more irregular than in control birds in both years. Analysis of locomotor activity showed that birds were still synchronized to the underlying light-dark cycle. We suggest that the lack of reproductive activity and irregular molt progression were possibly the results of i) birds being stuck in a photorefractory state and/or ii) chronic stress. Our data show that chronic low intensities of light at night can dramatically affect the reproductive system. Future studies are needed in order to investigate if and how urban animals avoid such negative impact and to elucidate the physiological mechanisms behind these profound long-term effects of artificial light at night. Finally we call for collaboration between scientists and policy makers to limit the impact of light pollution on animals and ecosystems.  
  Address Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany ; Department of Biology, University of Konstanz, Konstanz, Germany  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24376865; PMCID:PMC3869906 Approved no  
  Call Number IDA @ john @ Serial 49  
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Author Russ, A.; Reitemeier, S.; Weissmann, A.; Gottschalk, J.; Einspanier, A.; Klenke, R. url  doi
openurl 
  Title Seasonal and urban effects on the endocrinology of a wild passerine Type Journal Article
  Year 2015 Publication Ecology and Evolution Abbreviated Journal Ecol Evol  
  Volume 5 Issue 23 Pages 5698–5710  
  Keywords Animals; endocrinology; blackbirds; birds; European blackbird; Turdus merula; estrone; testosterone; corticosterone  
  Abstract In order to maximize their fitness, organisms in seasonal environments rely on external cues to optimally time their life-history stages. One of the most important zeitgeber to time reproduction is the photoperiod, but further environmental cues are assessed to fine-tune reproduction due to year-to-year variation in environmental conditions. However, in urbanized environments, the pervasive artificial light at night has altered the natural signal of light and darkness. Accordingly, artificial light at night was repeatedly shown to affect avian reproductive physiology and to advance seasonal reproduction in birds. However, these experiments were mainly conducted in the absence of further environmental cues to facilitate the investigation of the mechanisms which are still poorly understood. Here, we investigate whether the endocrine system of free-ranging European blackbirds (Turdus merula) correlates with the amount of artificial light at night along a rural to urban gradient while the birds still encounter complementary environmental cues including seasonal variation in day length and temperature. Testosterone and estrone were assessed as metabolites in fecal samples and corticosterone in blood from mist-netted blackbirds. We demonstrate that seasonal fluctuations in abiotic factors, individual conditions, but also light at night affect the reproductive and stress physiology of wild European blackbirds. Elevated artificial night light intensities were significantly positively correlated with corticosterone and negatively with female estrone levels. No effects of artificial light were found for testosterone levels. Our results suggest that female blackbirds in particular perceive even low levels of artificial light at night as a weak but chronic stressor that interacts with the hypothalamic-pituitary-gonadal axis and leads to a reduced secretion of reproductive hormones. These findings point out that the impacts of light pollution are diverse and we only slowly disentangle its multiple effects on physiology, ecology, and biodiversity.  
  Address Department of Conservation Biology, Helmholtz-Centre for Environmental Research – UFZ, Permoserstraße 15, 04318 Leipzig, Germany  
  Corporate Author Thesis  
  Publisher Wiley Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2045-7758 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ kyba @ Serial 1303  
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