Road mortality of vertebrates in the world’s largest continuous wetland: insights from the Northern Pantanal

Highways convert continuous landscapes into fragmented ecosystems, resulting in wildlife mortality due to roadkill. Herein, we evaluate when and which species of vertebrates are affected by roadkill on two roads (Route 1: 85 km; Route 2: 95 km) between the Cerrado savannas and Pantanal floodplain. Along 36 months (March 2017 to February 2020), we recorded 2,259 carcasses of vertebrates (76%; 173 species) on Route 1 and 713 (24%; 114 species) on Route 2, totaling 2,973 carcasses of 206 species, 14 of those considered globally threatened. Mammals and reptiles were the most frequently killed, and anurans and birds were detected in lower numbers. Except for anurans, we found significant differences in the species composition of the carcasses among the roads and the seasons. In the dry season, we recorded higher roadkill rates and changes in species composition on Route 2 and for mammals on Route 1. In contrast, most reptile and bird roadkill occur in the rainy season. Previous studies indicate that roadkill is higher in areas with higher populations’ abundance and that medium and large species are mostly affected. Landscape variation and consequent intraregional scale differences can explain the dissimilarities. In the dry season, there is an increase in roadkill when environments with water are more requested; in the rainy season, when food resources are more available, and many species reproduce. The roads studied are often affected by fires and present great regional and national importance, making the study of vertebrate roadkill impacts still more important for local wildlife conservation.