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Author Kehoe, R.C.; Cruse, D.; Sanders, D.; Gaston, K.J.; van Veen, F.J.F.
Title Shifting daylength regimes associated with range shifts alter aphid-parasitoid community dynamics Type Journal Article
Year 2018 Publication Ecology and Evolution Abbreviated Journal Ecol Evol
Volume 8 Issue 17 Pages 8761-8769
Keywords (up) Animals; Ecology
Abstract With climate change leading to poleward range expansion of species, populations are exposed to new daylength regimes along latitudinal gradients. Daylength is a major factor affecting insect life cycles and activity patterns, so a range shift leading to new daylength regimes is likely to affect population dynamics and species interactions; however, the impact of daylength in isolation on ecological communities has not been studied so far. Here, we tested for the direct and indirect effects of two different daylengths on the dynamics of experimental multitrophic insect communities. We compared the community dynamics under “southern” summer conditions of 14.5-hr daylight to “northern” summer conditions of 22-hr daylight. We show that food web dynamics indeed respond to daylength with one aphid species (Acyrthosiphon pisum) reaching much lower population sizes at the northern daylength regime compared to under southern conditions. In contrast, in the same communities, another aphid species (Megoura viciae) reached higher population densities under northern conditions. This effect at the aphid level was driven by an indirect effect of daylength causing a change in competitive interaction strengths, with the different aphid species being more competitive at different daylength regimes. Additionally, increasing daylength also increased growth rates in M. viciae making it more competitive under summer long days. As such, the shift in daylength affected aphid population sizes by both direct and indirect effects, propagating through species interactions. However, contrary to expectations, parasitoids were not affected by daylength. Our results demonstrate that range expansion of whole communities due to climate change can indeed change interaction strengths between species within ecological communities with consequences for community dynamics. This study provides the first evidence of daylength affecting community dynamics, which could not be predicted from studying single species separately.
Address College of Life and Environmental Sciences University of Exeter Penryn Cornwall UK
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN 2045-7758 ISBN Medium
Area Expedition Conference
Notes PMID:30271543; PMCID:PMC6157684 Approved no
Call Number NC @ ehyde3 @ Serial 2100
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Author Nankoo, S.; Raymond, S.; Galvez-Cloutier, R.
Title The impact of the Jacques Cartier bridge illumination on the food chain: from insects to predators Type Journal Article
Year 2019 Publication Community Ecology Abbreviated Journal Community Ecology
Volume 20 Issue 2 Pages 172-180
Keywords (up) Animals; Ecology
Abstract Artificial light at night can impact numerous diurnal species by influencing their distribution and habits. In this study, artificial lights placed on the Jacques Cartier bridge in Montreal, Canada were evaluated to determine their impact on insects, insectivorous birds and peregrine falcons. The impact was measured the year the illumination begun and the year following (two years in total). Insect distribution and abundance at three different sites around the bridge was measured. Insectivorous bird abundance and activity were evaluated by observing the cliff swallow as a proxy. Peregrine falcon presence and nesting behavior at the bridge was measured. Insects (aerial and aquatic) were found to be more abundant closer to the illuminated part of the bridge and particularly in the year following the illumination's beginning. Similarly, cliff swallows were more abundant at the bridge the year following the start of the illumination and their activity was more important closer to the illuminated section. Peregrine falcons were only present at the bridge in the year following the beginning of the illumination and specifically at the illuminated part of the bridge. No nesting was detected. These three groups are connected to each other through a food chain in which insect abundance impacts insectivorous bird abundance, which in turn impacts peregrine falcon presence. The illumination therefore positively impacts these three groups separately and together through their food chain. This research highlights the importance of monitoring bird and insect population close to the bridge and further continuation of these observations are necessary to determine if the observed tendency will continue to develop throughout the years.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1585-8553 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2705
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Author Gaston, K.J.; Holt, L.A.
Title Nature, extent and ecological implications of night‐time light from road vehicles Type Journal Article
Year 2018 Publication Journal of Applied Ecology Abbreviated Journal
Volume 55 Issue 5 Pages 2296-2307
Keywords (up) Animals; Ecology; Lighting; Review
Abstract The erosion of night‐time by the introduction of artificial lighting constitutes a profound pressure on the natural environment. It has altered what had for millennia been reliable signals from natural light cycles used for regulating a host of biological processes, with impacts ranging from changes in gene expression to ecosystem processes.

Studies of these impacts have focused almost exclusively on those resulting from stationary sources of light emissions, and particularly streetlights. However, mobile sources, especially road vehicle headlights, contribute substantial additional emissions.

The ecological impacts of light emissions from vehicle headlights are likely to be especially high because these are (1) focused so as to light roadsides at higher intensities than commonly experienced from other sources, and well above activation thresholds for many biological processes; (2) projected largely in a horizontal plane and thus can carry over long distances; (3) introduced into much larger areas of the landscape than experience street lighting; (4) typically broad “white” spectrum, which substantially overlaps the action spectra of many biological processes and (5) often experienced at roadsides as series of pulses of light (produced by passage of vehicles), a dynamic known to have major biological impacts.

The ecological impacts of road vehicle headlights will markedly increase with projected global growth in numbers of vehicles and the road network, increasing the local severity of emissions (because vehicle numbers are increasing faster than growth in the road network) and introducing emissions into areas from which they were previously absent. The effects will be further exacerbated by technological developments that are increasing the intensity of headlight emissions and the amounts of blue light in emission spectra.

Synthesis and applications. Emissions from vehicle headlights need to be considered as a major, and growing, source of ecological impacts of artificial night‐time lighting. It will be a significant challenge to minimise these impacts whilst balancing drivers' needs at night and avoiding risk and discomfort for other road users. Nonetheless, there is potential to identify solutions to these conflicts, both through the design of headlights and that of roads.
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Notes Approved no
Call Number GFZ @ kyba @ Serial 1841
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Author Russ, A.; Reitemeier, S.; Weissmann, A.; Gottschalk, J.; Einspanier, A.; Klenke, R.
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 (up) 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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Author Einfalt, L.M.; Grace, E.J.; Wahl, D.H.
Title Effects of simulated light intensity, habitat complexity and forage type on predator–prey interactions in walleye Sander vitreus Type Journal Article
Year 2012 Publication Ecology of Freshwater Fish Abbreviated Journal
Volume 21 Issue 4 Pages 560–569
Keywords (up) Animals; habitat; light intensity; predator–prey interactions; walleye
Abstract Predator-prey interactions can be influenced by the behaviour of individual species as well as environmental factors. We conducted laboratory experiments to test for the influences of two abiotic factors (light intensity and habitat complexity) on predator–prey interactions between walleye Sander vitreus and two prey species, bluegill Lepomis macrochirus and golden shiner Notemigonus crysoleucas. Three light intensities were simulated (day, twilight and night) in the presence or absence of simulated vegetation. Observations of predator behaviour indicated that walleye increased activity and foraging success with decreasing light levels and had most success capturing dispersed, closer prey. While schooling could not be maintained as light levels diminished, prey decreased predation vulnerability by moving into vegetation or higher in the water column. Throughout all treatments, bluegill were more evasive to capture as the number of strikes was similar on both prey but capture rates were higher for golden shiner. Although light intensity and simulated habitat complexity affected predator and prey behaviour, these factors did not interact to influence foraging success of walleye. To fully understand predator and prey behaviours in fishes, an understanding of species-specific responses to abiotic and biotic factors is necessary.
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Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 388
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