The Effects of Artificial Night Lighting on Nocturnal Activity of the Red- backed Salamander, Plethodon cinereus
Meagan Sudik*, Bryant Buchanan, and Sharon Wise
Anthropomorphic sources of pollution are of increasing concern as humans continue to develop areas in and near natural habitats. One of these sources, light pollution, caused by artificial night lighting (ANL), has the potential to negatively impact the physiology and behavior of nocturnal species. Previous studies have found that amphibians alter their behavior in response to constant, bright ANL. We are examining the effects of ANL comparable to commonly encountered levels of light pollution on the nocturnal behavior of the terrestrial Red- backed-Salamander, Plethodon cinereus. In a controlled laboratory experiment, we are exposing salamanders (n=32) to four different nocturnal ambient illuminations of 10-4 lx (dark control), 10-2 lx, 1 lx, and 100 lx in a repeated-measures design, where each salamander is exposed to each light treatment for 10 days in random order. All salamanders are exposed to a 12L: 12D photoperiod with 100 lx daylight and acclimated to the control photoperiod for 10 days between each treatment. We are observing the salamander’s behavior for three 24- hour periods during those 10 days (first, fifth, and tenth days) using infrared cameras. We predict that the total nocturnal activity (time spent outside a dark cover object in the middle of the chambers) will be reduced in salamanders under higher nocturnal ambient illumination (100, 1, and 10-2 lx), compared to those under normal dark nocturnal illumination (10-4 lx). We also predict more daytime activity in salamanders exposed to the 100 lx nocturnal treatment as normal circadian rhythm should be disrupted.