Roadkill threatens future of iconic Latin American species

Image Credit: "Sloth" by ZeMoufette is licensed under CC BY 2.0.

Written by Clara Grilo

March 7, 2023

The future of sloths, anteaters, and other wild animals is at risk due to the construction of new roads in key regions of Latin America, according to new research.


A team of ecology experts from the University of Reading (UK) and the Federal University of Lavras (Brazil) has mapped how collisions with road traffic in Central and South America are threatening the survival of bird and mammal species.

In particular, they found that building new roads in regions of the Amazon would be catastrophic for biodiversity, according to the researchers in the study published in the journal Biological Conservation.

Sloths and anteaters, part of the mammal group Pilosa, are particularly vulnerable to being killed by vehicles on roads, with 80% of their species reported as victims of vehicular traffic. This compares to just 8.5% for all mammals. Among birds, cuckoos, nightjars, vultures, and pelicans were identified as species with a higher likelihood of experiencing high mortality rates on roads. The research team suggests that these birds and mammals should be given special protection to counter this impact.

“The expansion of roads in Latin America continues at a rapid pace, but this could have a disastrous impact on many species in this part of the world. It is well known that deforestation in the Amazon has enormous impacts on biodiversity, with new roads playing a major role in providing access to legal and illegal loggers. Our research shows that traffic on roads causes significant damage to many bird and mammal species, with sloths and anteaters particularly vulnerable,” said Pablo Medrano-Vizcaíno, a doctoral student who led the study at the University of Reading.

“With more than 12,000 kilometers of new roads planned in the coming years in this region, we must carefully consider the impact on wildlife, so that we can take conservation measures to protect vulnerable species,” said Clara Grilo, co-author of the research and professor at the Federal University of Lavras (Brazil) and the Center for Environmental and Marine Studies (CESAM) at the University of Lisbon (Portugal).

“Millions of birds and mammals already die on Latin American roads each year, and more will die as more roads are built. It is important to understand the cumulative impact of this ecological damage, so that efforts can be made to plan future road networks and conservation efforts in advance. Otherwise, our roadside verges could become the cemeteries of iconic species,” concluded Manuela González-Suárez, co-author of the study and associate professor of ecological modeling at the University of Reading.

Roadkill rate

The research team analysed the roadkill rates, life traits, habitat preferences, and conservation status of 346 bird species and 159 mammal species in Latin America. Using this data, they discovered that sloths, anteaters, and a variety of birds are particularly vulnerable to road hazards in tropical areas of the Amazon, such as western Brazil, Peru, and Colombia. In these regions, there are currently few roads and many vulnerable species inhabit them.


The researchers also mentioned that roads in Central America and northwestern South America have been poorly studied, but many birds and mammals vulnerable to traffic collisions inhabit these areas

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