Roadkill threatens future of iconic Latin American species

The future of sloths, anteaters and other wildlife are under threat from new roads being built in key regions of Latin America, new research has found.

A team of ecology experts at the University of Reading and University of Lisbon have mapped how collisions with road traffic in many parts of central and South America are threatening the survival of species of birds and mammals.

In particular, they found that new roads in regions of the Amazon could be disastrous for biodiversity, the researchers say in the study, published today (Tuesday 27 February) in the journal Biological Conservation.

Sloths and anteaters – part of the Pilosa mammal group – are particularly vulnerable to being killed on the roads, with 80% of known species reported as having been victim of traffic. This is compared to just 8.5% for all mammals. Among birds, cuckoos, nightjars, vultures and pelicans were all identified as species with high rates of road mortality. The research team suggest these birds and mammals should be given special protection to counter this impact.

Pablo Medrano-Vizcaíno, a PhD researcher who led the study at the University of Reading, said: “Road expansion in Latin America continues at a great pace, but this could have a disastrous impact on many species in this part of the world.

“It’s well-known that deforestation in the Amazon has huge impacts on biodiversity, with new roads playing a role in providing access of legal and illegal loggers. Our research shows that the road traffic itself causes significant harm to many species of birds and mammals, with sloths and anteaters particularly vulnerable.

“With more than 12,000 kilometres of new highway planned in the next few years in this region, we need to think carefully about the impact on wildlife, so we can take conservation measures to protect vulnerable species.”

Dr Manuela González-Suárez, co-author of the study and associate professor of ecological modelling at the University of Reading, said: “Millions of birds and mammals already die on roads in Latin America each year, and more will die as extra roads are built.

“It is important that planners understand the cumulative impact of this ecological damage, so that efforts be made to plan future road networks and conservation efforts in advance. Otherwise our road verges could become the graveyards of iconic species.”

Roadkill rate

The research team analysed the roadkill rates, life traits, habitat preferences and conservation status of 346 species of birds and 159 species of mammals in Latin America.

Using this data, they found that sloths, anteaters, and a range of birds are particularly vulnerable to the dangers of roads in tropical areas of the Amazon, such as western Brazil, Peru and Colombia. In these regions, few roads currently exist, and many vulnerable species live.

The researchers also suggest that regions of Central America and North-Western South America are understudied, yet have many roads and many birds and mammals vulnerable to being killed by traffic.

Pablo Medrano-Vizcaíno, Clara Grilo, Manuela González-Suárez, Research and conservation priorities to protect wildlife from collisions with vehicles, Biological Conservation, Volume 280, 2023, 109952, ISSN 0006-3207, https://doi.org/10.1016/j.biocon.2023.109952.