Dawes 2009 Ichthyology Herpetology Meetings

Presented at 2009 Joint Meeting of Ichthyologists and Herpetologists, Portland, OR

Sharon Wise, Bryant Buchanan, and Patrick Dawes.

Artificial Night Lighting Alters Surface Activity of Red-backed Salamanders.

Expansion of human habitation near and within natural habitats increasingly exposes wildlife to pollutants. Light pollution, night lighting in naturally dark areas due to artificial sources, has the potential to alter the behavior of nocturnally-active amphibians. Exposure of amphibians to constant bright light in the laboratory causes changes in activity patterns, metabolism, and growth. However, the impact of artificial night lighting comparable to that in affected habitats has not yet been addressed widely in the literature. We examined changes in nocturnal activity of Red-backed Salamanders (Plethodon cinereus) exposed to natural and artificial night lighting in both the natural habitat and in the laboratory. On humid and rainy nights, these woodland salamanders emerge from under cover objects and forage above-ground. We hypothesized that artificial night lighting would delay emergence from under cover objects. We tested this hypothesis in twelve 16-m forest transects in which six were artificially lit (10-2 lx) and six were left dark (10-4 lx). We found fewer salamanders active 1 h after dark in the lighted transects, suggesting a delay in time of emergence for salamanders in lighted transects. In a laboratory experiment, we tested this hypothesis by examining the effect of four different nocturnal light levels (10-4 to 100 lx) on emergence time and nocturnal activity. Salamanders emerged sooner and were active longer under darker conditions. Our results suggest that artificial night lighting has the potential to alter the normal nocturnal activity of salamanders associated with foraging and breeding.
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