Alex Rohacek, Bryant Buchanan, and Sharon Wise
The Effects of Artificial Night Lighting on the Nocturnal Activity of the Terrestrial Red-backed Salamander, Plethodon cinereus
As human development encroaches into natural habitats, artificial night lighting increasingly becomes an additional stressor for wildlife. Nocturnal animals are especially vulnerable to artificial night lighting (ANL), as physiology and behavior of these species has evolved in nocturnally dark habitats. Studies exposing amphibians to constant bright light provide evidence for changes to normal metabolism, growth, and behavior, but few of these studies have used treatment ANL comparable to that found in affected natural habitats. We examined the effect of artificial night lighting on the nocturnal activity of the Red-backed salamander, Plethodon cinereus. Previous work using transects in a forested habitat found that salamanders emerged from under cover objects later when exposed to artificial night lighting than under natural dark conditions. In a controlled laboratory setting, we exposed salamanders (N = 16) to nocturnal illuminations of 1 lx, 10-2lx, or 10-4lx in a repeated-measures design: each salamander was exposed to each illumination for 10 d and then the behavior of the salamander was observed using infrared cameras for one night; we predicted that salamanders would delay emergence and exhibit less activity under higher nocturnal light levels than under lower light levels. Based on the results of this study and previous research, salamanders delay emergence when subjected to ANL, suggesting an effect of ANL on time available for foraging and breeding.