Effects of light and noise pollution on occupancy of gray treefrogs (Hyla versicolor) and green frogs (Lithobates clamitans) in Syracuse, NY

Artificial light at night (ALAN) and noise pollution have been shown to affect urban wildlife everywhere, but little is known about the effects of these variables on urban frogs. Our objective was to model the effects of ALAN and noise pollution (as well as a suite of other habitat variables) on site occupancy of gray treefrogs (Hyla versicolor) and green frogs (Lithobates clamitans) in the city of Syracuse, New York, USA. We conducted frog call surveys at a total of 43 sites during the breeding seasons of 2018–2020 throughout the Syracuse metropolitan area. Estimated gray treefrog occupancy (with 95% confidence intervals in parentheses) ranged from 40% (24–72%) to 66% (43–81%) and was highest at sites with minimal ALAN, low noise pollution levels, and high tree coverage. Green frog occupancy rates ranged from 24% (17–30%) to 64% (35–85%) and was highest at sites near standing water but was not as affected by ALAN or noise pollution as was gray treefrog occupancy. Ultimately, frog occupancy was negatively related to ALAN and noise pollution and thus conservation plans for urban frogs should address both of these variables.