Abstract Listing by Session


SY41 - Artificial Lights and Nature: Challenges for Dusk-to-Dawn Conservation Management

Salon 3      Sunday, 10:30 - 16:00

   10:30  Artificial Night Lighting Alters Growth and Development of Aquatic Snails and Frog Larvae. Buchanan, B.*, Utica College ; Wise, S., Utica College; McCarthy, T., Utica College; Savage, H., Utica College; June, J., Utica College; Bingel, K., Utica College
The expanded global use of artificial night lighting increasingly exposes organisms to unnatural patterns of illumination within natural habitats. Growth and development of vertebrates and invertebrates is controlled in part by hormones that are produced in daily cycles associated with illumination-dependent shifts in the production of photoperiodic hormones like melatonin. We studied growth and development of snails (Physa acuta) and frog larvae (Xenopus laevis) exposed to different amounts of light at night in laboratory studies. All animals were exposed to diurnal illuminations of 100 lx and varying nocturnal illuminations of 0.0001 lx (starlight; dark control), 0.01 lx (moonlight), 1.0 lx (twilight), and 100 lx (dim room lighting). After 37 days of larval development, we photographed and measured frog larvae and established their developmental stage. Frog larvae grew the fastest when exposed to small to moderate amounts of artificial night lighting and their development was significantly delayed at these illuminations relative to dark controls. Snails monitored over 120 days responded similarly with peak growth occurring at low to moderate levels of artificial night lighting. Our results suggest that even small amounts of light pollution commonly found in aquatic habitats can significantly alter growth and development of aquatic organisms.
   10:45  Chronobiological disruption and nature conservation Haim A*, University of Haim
Most organisms are adapted to the daily and seasonal light variations that result from planetary motion. The biological clock of such organisms is entrained by these variations, acts both as a clock and a calendar. Light at night (LAN) and Light interference (LI) disrupt these circadian rhythms with deleterious effects. Several studies in our laboratory show that to short day acclimated rodents, LAN signals a long day acclimation and thereby disrupts seasonality. This creates a "seasons-out-of-time" effect, discovered in the thermoregulatory system of the social vole Microtus socialis. LAN may change conductance properties of the integument, meaning that exposure to low ambient temperatures will result in hypothermia if heat production cannot compensate for heat loss. These changes can be attributed to the interruption of melatonin production and secretion by the pineal gland. Rapid increase in light intensity (via an on/off switch) from minimal levels to 450 lux forms a source of stress and in M. socialis resulted in an increase of stress hormones levels. A comparative thermoregulatory study (diurnal versus nocturnal) Gerbils revealed different patterns likely stemming from activity time. LAN and LI also have a negative impact on the immune system. With the modern increase in LAN and LI, conservation biologists should be aware of these negative impacts on animal welfare in relation to light intensity, wavelength and duration of exposure.
   11:00  Light alters movement of beach mice at the patch and landscape scales Wilkinson, E, University of Florida ; Branch, LC, University of Florida; Stoddard, MA*, University of Florida; Bird, BL, Oakland County Parks, MI
Effects of artificial light in coastal systems are poorly understood except with respect to sea turtles. Beach mice (Peromyscus polionotus spp.) are vulnerable to habitat loss from hurricanes, development, and introduced predators, and these factors likely are exacerbated by artificial light because light increases risks associated with moving across open landscapes. To project how artificial light might influence Santa Rosa beach mouse movement at the landscape scale, we used foraging paths to evaluate the effect of natural light levels (new vs. full moon) on: 1) width of open sand gaps crossed by mice during foraging, 2) size of resource patches, and 3) landscape context of foraging. Moonlight had a strong, negative effect on foraging activity of beach mice. Gap width crossed was similar under all conditions, but average size of patches visited was smaller during full vs. new moon periods, likely reflecting the need for animals to maximize cover from predators. Mice left dunes over a narrower range of angles during full moon periods, indicating they restrict foraging to certain parts of the landscape when perceived risk is high. Our results reinforce earlier research showing increased light (artificial or moonlight) restricts foraging time in beach mice and emphasize the importance of including coastal lighting in conservation planning for terrestrial species.
   11:15  Impacts of Artificial Night Lighting on the Behavior of Nocturnal Salamanders Wise, Sharon*, Utica College ; Buchanan, Bryant, Utica College; Dawes, Patrick, Utica College; Racchumi, Joelle, Utica College; Rohacek, Alex, Utica College
Artificial night lighting (ANL) is of increasing concern as human habitation encroaches into natural habitats. The effect of ANL on amphibians has not yet been widely studied. We examined the impact of ANL on the nocturnal activity of terrestrial salamanders (Plethodon cinereus) in the natural habitat and in the laboratory. These salamanders remain under cover objects during daylight hours and emerge above-ground to forage and mate at night. We hypothesized that ANL affects the nocturnal behavior of salamanders by delaying emergence from under cover objects. We tested this hypothesis using forest transects (N= 12) in which half were dimly, artificially lit (10-2 lx) and six were left dark (10-4 lx). Fewer salamanders were active 1 h after dark in the lighted transects, suggesting a delay in time of emergence. In laboratory experiments in which salamanders were exposed to nocturnal light from 10-4 to 100 lx, we found that salamanders were more active at higher than at lower illuminations when no cover was available, but were less active at higher than at lower illuminations when cover objects were available. Results from the laboratory and field provide evidence that salamanders are avoiding higher nocturnal illuminations, resulting in increased activity when cover is absent and delayed emergence from cover under higher illuminations. Thus, ANL has the potential to alter the normal nocturnal foraging and breeding activity of salamanders.
   11:30  Shedding light on bat behaviour - street-lights disturb commuting bats Stone, E.L*, University of Bristol
Artificial lighting schemes can damage bat foraging habitat directly through loss of land and fragmentation or indirectly by severing commuting routes from roosts, polluting commuting and foraging habitat. The effect of street lighting on bat activity was tested in experiments along commuting routes of lesser horseshoe bats at eight sites across Wales and South West England. Hedgerows were illuminated at a mean of 53 lux using two portable high pressure sodium street lights. Bat activity was recorded using AnaBat remote acoustic detectors. Repeated-measures analysis of variance (ANOVA) was used to test the effect of experimental treatment on bat activity. Treatment type had a significant effect on bat activity (p = <0.01). Contrasts demonstrated that all light treatments were significantly different from controls (p = <0.05), demonstrating that high pressure sodium light has a negative effect on lesser horseshoe bat activity. This study has provided the first empirical evidence of a negative effect of high pressure sodium lights on commuting horseshoe bats and has significant conservation implications for bat habitat management at sites affected by light pollution. Results from this study will be used to develop evidence based mitigation guidance for bats and lighting in the UK.
   11:45  Attraction of nocturnal insects to street lights with special regard to LEDs Eisenbeis, G*, Non-SBC member ; Eick, K, Non-SBC member
Artificial lighting is a key factor for nocturnal insects, which are attracted in huge numbers to many sorts of light sources. Millions of lights illuminate urban areas and extend deeply into the open landscape, especially along roads. In the summer of 2008 the City of Düsseldorf initiated a study to evaluate the insect flight activity to street lights. We compared modern lamp types such as metal halide and LEDs to older lamp types, e.g. high pressure mercury lamps, high pressure sodium lamps and fluorescent lamps. From June 24 to September 2, we used 20 traps to catch insects flying around the street lamps in a suburban area of Düsseldorf. Traps were exposed in a daily pattern. We analyzed 964 nightly samples containing 33,896 insects belonging to 13 insect orders, of which 7 predominated while 6 were counted only in lower numbers. In comparing the flight activity we used the attraction to the high pressure mercury lamps as reference (=100%). On this basis we determined a sequence of attraction for all insect orders down to -80%. The 7 most common orders behaved very differently, e.g. the moths were attracted to minimum values in the range of -95%. Two orders were found to be attracted stronger than the reference. The most significant differences regarding the bulk of insects were between LEDs and all the other lamp types. They did not emit any UV and proved to be very insect friendly.
   14:00  Attraction of petrels to artificial lights in the Canary Islands Rodríguez, A*, Estación Biológica de Doñana CSIC ; Rodríguez, B, SEO/BirdLife
The extent and intensity of artificial night lighting has increased with urban development worldwide. The resulting light pollution is responsible for mortality among many petrel species that are active at night on their breeding grounds. We report light-induced mortality of petrels during a 9-year study on Tenerife, Canary Islands. A total of 9880 birds from nine species were found grounded, the majority of which were Cory’s Shearwaters. Most grounded birds were fledglings (96%), which fall apparently while leaving their nesting colony for the first time. For almost all species, grounding showed a seasonal pattern linked with their breeding cycle. Certain phases of the moon influenced grounding of shearwaters, with the extent of grounding being reduced during phases of full moon. The ratio of fledglings attracted to lights to fledglings produced annually varied between species and years. Mean rates of adult mortality also varied between species. These light-induced mortality rates are of concern for petrels and small shearwaters. Thanks to efforts involving cooperation with human residents, 95% of grounded birds returned to the wild. To minimize this impact we recommend several conservation measures: continuing rescue campaigns, shielding upward radiation and reduction of light emissions during the fledging peaks. Furthermore, a monitoring program for petrel populations must be implemented, as well as further studies to assess the fate of released fledglings and continued research to address why petrels are attracted to lights.
   14:15  Tracking Birds Migrating at Night through an Urban-rural Corridor and Quantifying the Effects of Light and Noise Pollution Clark, J.A.*, Fordham University ; Bricklin, R., Fordham University ; Chan, O., Fordham University ; Ross, J., Fordham University ; Farnsworth, A., Cornell University
Many migratory bird species are in serious decline. Understanding how birds assess and use increasingly large, brightly lit, and noisy cities as they travel through urban landscapes and encounter tall buildings, towers, and aircraft is essential to their conservation. However, little is known about how birds evaluate obstacles presented by cities during migration, which generally occurs at night and is confounded by ubiquitous light pollution. We test a novel approach to tracking birds migrating through an urban-rural corridor and quantifying the effects of light and noise pollution on such migration. We recorded nocturnal flight calls at multiple sites along an urban-rural corridor from New York City north and simultaneously collected data on measures of light and noise. Some studies suggest birds are drawn to brightly lit areas and that bird density is artificially increased in cities. Consistent with these studies, we documented more nocturnal flight calls in brighter, noisier locations than in nearby darker, quieter green spaces. These higher calling rates may also reflect increased confusion of birds in noisy urban environments.
   14:30  Bird-friendly Light? Poot, H.*, Max Planck Institute for Ornithology ; Donners, M.A.H., Philips Lighting; Marquenie, J.M., Shell EP Europe (NAM B.V.)
Millions of birds are affected by artificial light emitted from offshore installations they encounter during migration each year. Many are attracted and disoriented by the lights, causing collisions and exhaustion resulting in death. Because safety requirements or technical design rule out switching off these lights, new solutions are needed. Our idea was to investigate the effect of changing the spectral composition of the light on bird reactions. In 2003 we did a pilot study at the North Sea coast during autumn migration with colored filters in front of light sources, which showed that nocturnal migrants react stronger to white and red light, compared with blue and green light. Based on these results and a literature survey, we hypothesized that the red part of the spectrum (575–650 nm) causes most problems for migrating birds, and developed new light types containing less red, whilst still ensuring safe working conditions and good visibility for humans. We tested these light types in the field and found a positive correlation between the relative intensity of red in the spectrum and birds’ reactions to the light sources, independent of total light intensity. The mechanisms underlying these results still need further investigation, but we already managed to develop a commercially available light type that may be defined as (more) bird-friendly.
   14:45  Considerations in designing wildlife-friendly night lighting Longcore, T*, The Urban Wildlands Group ; Rich, C, The Urban Wildlands Group
Conservation lands with public access, including wildland parks, are places to be able to see and enjoy the solitude of unspoiled nature, where the natural rhythms of life are allowed to flourish with minimal disturbance from human interference. Managers of such lands therefore must balance the need to provide visitor infrastructure with its adverse effects on the environment. Although night lighting is considered an essential element for visitors in many circumstances, night lighting has a range of adverse ecological consequences for ecosystems and wildlife. With some planning, however, the effects of lighting on species and ecosystems can be reduced and in some instances avoided altogether. We provide an overview of the effects of artificial night lighting on wildlife and considerations for designing or retrofitting lighting that minimize impacts to wildlife and the nocturnal environment. These considerations are organized by habitat type: dunes, beaches, and shorelines; deserts and scrublands; wetlands; islands, oceans, and reefs; grasslands; deciduous and evergreen forests; alpine and tundra; and urban environments. Within the unique context of each of these environments, managers should consider five questions about lighting systems that address need, duration, intensity, direction, and spectrum as they relate to potential adverse effects.