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Author Gerrish, G.A.; Morin, J.G.; Rivers, T.J.; Patrawala, Z.
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 (up) 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 0029-8549 ISBN Medium
Area Expedition Conference
Notes PMID:19330516 Approved no
Call Number IDA @ john @ Serial 16
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Author Kyba, C.C.M.; Ruhtz, T.; Fischer, J.; Hölker, F.
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 (up) 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:21399694; PMCID:PMC3047560 Approved no
Call Number IDA @ john @ Serial 20
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Author Perkin, E.K.; Hölker, F.; Richardson, J.S.; Sadler, J.P.; Wolter, C.; Tockner, K.
Title The influence of artificial light on stream and riparian ecosystems: questions, challenges, and perspectives Type Journal Article
Year 2011 Publication Ecosphere Abbreviated Journal Ecosphere
Volume 2 Issue 11 Pages art122
Keywords aquatic invertebrates; artificial illumination; ecosystems; fish; multiple stressors; riparian; streams; urbanization
Abstract Artificial light at night is gaining attention for its potential to alter ecosystems. Although terrestrial ecologists have observed that artificial light at night may disrupt migrations, feeding, and other important ecological functions, we know comparatively little about the role artificial light might play in disrupting freshwater and riparian ecosystems. We identify and discuss four future research domains that artificial light may influence in freshwater and associated terrestrial ecosystems, with an emphasis on running waters: (1) dispersal, (2) population genetics and evolution, (3) ecosystem functioning, and (4) potential interactions with other stressors. We suggest that future experimental and modeling studies should focus on the effects of different spectral emissions by different light sources on freshwater organisms, the spatial and temporal scale over which artificial light acts, and the magnitude of change in light at night across the landscape relative to the distribution of running and standing waters. Improved knowledge about the effects of artificial light on freshwater ecosystems will inform policy decisions about changes to artificial light spectral emissions and distributions.

Read More: http://www.esajournals.org/doi/abs/10.1890/ES11-00241.1
Address
Corporate Author (up) Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2150-8925 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 24
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Author Hölker, F.; Wolter, C.; Perkin, E.K.; Tockner, K.
Title Light pollution as a biodiversity threat Type Journal Article
Year 2010 Publication Trends in Ecology & Evolution Abbreviated Journal Trends Ecol Evol
Volume 25 Issue 12 Pages 681-682
Keywords *Biodiversity; Biological Clocks; Biological Evolution; Ecosystem; *Environmental Monitoring; *Environmental Pollutants; Light/*adverse effects
Abstract
Address
Corporate Author (up) 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 0169-5347 ISBN Medium
Area Expedition Conference
Notes PMID:21035893 Approved no
Call Number IDA @ john @ Serial 36
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Author Schoech, S.J.; Bowman, R.; Hahn, T.P.; Goymann, W.; Schwabl, I.; Bridge, E.S.
Title The effects of low levels of light at night upon the endocrine physiology of western scrub-jays (Aphelocoma californica) Type Journal Article
Year 2013 Publication Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology Abbreviated Journal J Exp Zool A Ecol Genet Physiol
Volume 319 Issue 9 Pages 527-538
Keywords Animals; Corticosterone/blood; Ecosystem; Female; *Light; Male; Melatonin/blood; Passeriformes/*physiology; *Photoperiod; Reproduction/*physiology; Testosterone/blood
Abstract Florida scrub-jays (Aphelocoma coerulescens) in the suburbs breed earlier than jays in native habitat. Amongst the possible factors that influence this advance (e.g., food availability, microclimate, predator regime, etc.), is exposure to artificial lights at night (LAN). LAN could stimulate the reproductive axis of the suburban jays. Alternatively, LAN could inhibit pineal melatonin (MEL), thus removing its inhibitory influence on the reproductive axis. Because Florida scrub-jays are a threatened species, we used western scrub-jays (Aphelocoma californica) to investigate the effects of LAN upon reproductive hormones and melatonin. Jays were held under conditions in which the dark-phase of the light:dark cycle was without illumination and then under low levels of LAN. Under both conditions, birds were exposed first to short-days (9.5L:14.5D) that were gradually increased to long-days (14.5L:9.5D). At various times, blood samples were collected during the light part of the cycle to measure reproductive hormones (luteinizing hormone, LH; testosterone, T; and estradiol, E2 ). Similarly, samples to assess melatonin were collected during the dark. In males, LAN caused a depression in LH levels and levels were approximately 4x greater under long- than short-days. In females, there was no effect of LAN or photoperiod upon LH. LAN resulted in depressed T levels in females, although there was no effect on T in males. E2 levels in both sexes were lower under LAN than under an unlighted dark-phase. Paradoxically, MEL was higher in jays under LAN, and under long-days. MEL did not differ by sex. LAN disrupted the extraordinarily strong correlation between T and E2 that existed under unlighted nocturnal conditions. Overall, our findings fail to support the hypothesis that LAN stimulates the reproductive axis. Rather, the data demonstrate that LAN tends to inhibit reproductive hormone secretion, although not in a consistent fashion between the sexes.
Address Department of Biological Sciences, University of Memphis, Memphis, Tennessee
Corporate Author (up) 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 1932-5223 ISBN Medium
Area Expedition Conference
Notes PMID:23970442 Approved no
Call Number IDA @ john @ Serial 37
Permanent link to this record