Wildlife-Crossing Mitigation Effectiveness with Traffic Noise and Light

Wildlife crossing structures (WCS) over or under highways have been proposed as a solution for road-related habitat fragmentation and wildlife collisions. To assure the efficacy of WCS, road related negative impacts that could cause animals to avoid WCS, such as noise and light, need to be considered. Human-sourced noise can affect habitat occupancy, and a suite of animal behaviors such as vigilance, communication, and predation efficiency, while artificial light, especially at night, can change animal’s perception of resources, foraging, mate selection, and navigation. Furthermore, the impact of noise and light varies among wildlife species, leading to differential responses within wildlife communities. To test whether traffic noise impacts species’ use of WCS, the authors quantified overnight (afternoon to early morning) road traffic noise, measured as dB(A), at 20 WCS positioned along four central California highways (I-5, I-80, 680 and 280), as well as historical WCS mammal use for 20 recorded days during the summer of 2012, 2015, and 2016. Using species richness inclusive of all taxa as the response variable, the only significant explanatory variable was annual average daily traffic (AADT) (p 800m from the highway) were monitored over a 20-day period, to further examine the impact of noise on WCS use. Species richness was greater (p View the NCST Project Webpage