Effect of COVID-19-induced social isolation on mammal roadkills on the BR-101 highway in Rio de Janeiro State, Brazil

The COVID-19 pandemic's enforced social isolation significantly disrupted numerous economic activities, notably road transport. This period, dubbed "anthropause," provided a unique moment to study its effects on wildlife, specifically mammal roadkill patterns on Brazil's BR-101/North-RJ highway. This research assessed whether reduced vehicle traffic during the pandemic's first year impacted mammal roadkill rates. Monitoring was conducted monthly from March 2019 to February 2021, spanning pre-pandemic and pandemic periods, across four 10-km highway sections. Findings indicated a 45% decrease in mammal roadkills during the pandemic, especially in the third quadrimester (November-2020 to February-2021) of the pandemic period (W = 77; p = 0.027). Of the nine taxa examined, Didelphis aurita and Coendou spinosus experienced the most significant reductions in roadkill rate. No link was found between climatic conditions and roadkill frequency, yet a noteworthy correlation emerged between vehicle traffic volume and roadkill rates (r = 0.281; p = 0.005). Despite a temporary decline in traffic, varying roadkill rates across highway segments pointed to diverse responses from environmental and traffic variations. The study emphasizes that even modest reductions in traffic can significantly lower roadkill rates, supporting the idea that the anthropause positively influenced the reduction of road-induced mortality among Neotropical mammals.