The international research team points out that road density in Europe is among the highest in the world. “Around half of the continent’s surface is a maximum of 1.5 kilometers from an asphalt road or railway line,” said ecologist Manuela Gonzalez-Suarez from the University of Reading. Roads would therefore pose a significant threat to wildlife and there are indications that the “road kill” could even lead to the complete disappearance of some species.
Under the direction of the Center for Environmental and Marine Studies (CESAM) in Lisbon, the scientists calculated the number of animals killed on the streets for 423 species of birds and 212 species of mammals. They found that small animals with a high population density that reached sexual maturity early are most likely to be run over. Nocturnal mammals and birds, which feed primarily on plants and seeds, also had higher mortality rates.
Among the birds, the blackbird leads the inglorious ranking with 11.94 animals killed per kilometer of the road and year. In mammals, it is the mosquito bat (Pipistrellus pygmaeus) with 1.76 animals killed per kilometer and year.
The scientists found “considerable differences between the regions” as they write in the work. The highest “road kill” values were found for both birds and mammals on roads in Central Europe, such as in Germany, Austria and the Czech Republic.
In birds, long-term survival of the hazel grouse (Bonasa bonasia) is most threatened by death on the street, in mammals that of the red and yellow ground squirrel (Spermophilus major). The scientists criticize that the long-term endangerment of species is currently not taken into account when assessing the effects of new roads on the animal world. “We run the risk of supporting the wrong species and doing nothing to help the most endangered species,” said Gonzalez-Suarez.