• Thu. Jun 30th, 2022

Roadkill offers a new way to sample animals in a region

ByRandall B. Phelps

May 6, 2021

TRAFFIC AND wildlife does not mix. Anyone who keeps an eye on the shoulders while driving on a country road knows this. But such carnage offers an opportunity for zoologists. Road accident tally is a rough and easy way to sample local animal populations, and is the basis of so-called citizen science efforts such as Project Splatter, in Britain, in which members of the public report what they found dead on the road, and where.

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Pablo Medrano Vizcaíno and Santiago Espinosa from the Catholic University of Ecuador, however, took things further by going in search of themselves. And, as they report in Biotropica, surveillance of road casualties can provide information on creatures that would otherwise be almost completely elusive.

Once a week, for six months, Mr. Medrano Vizcaíno and Dr. Espinosa walked three 33 km sections of roads crisscrossing in and around tropical forests and mountains near the Ecuadorian national parks of Cayambe Coca and Sumaco Napo-Galeras. Whenever they encountered a dead animal, they would stop, photograph it, note its GPS coordinates and identifies it as precisely as possible. If they failed to make an identification in the field, they would collect the carcass and bring it back to their lab for further study.

In total, they found 445 specimens. Some, like the 153 possums, were the kind of big critters the average passer-by might notice. But many were not. There were, for example, 43 amphibians. Frogs are common in tropical forests, but on the whole they weren’t frogs. On the contrary, about 80% of them were Cecilians, a little-known group of burrowing animals resembling worms. Ecuador is home to 24 species of caecilian. The exact species that were represented in the researchers’ collection are unclear, as individual species require specialized identification. But studying road accidents could be one way to learn more about them.

More extraordinary than that, among the 88 reptiles seen by Mr. Medrano Vizcaíno and Dr. Espinosa, one was a snake hitherto unknown to science. They also found an example of the northern tiger cat, a species believed to be on the verge of extinction.

A sampling method that relies on finding dead endangered animal species is obviously suboptimal. But Mr Medrano Vizcaíno and Dr Espinosa are hopeful that one of the outcomes of their work may be to identify road mortality hot spots and then try to find ways to discourage animals from going there.

This could, however, be tricky. The data they’ve collected so far suggests that these hot spots are often bridges over rivers. If the creatures themselves use them as waypoints, it can be difficult to dissuade them from doing so.

A version of this article was posted online on May 6, 2021

This article appeared in the Science and Technology section of the print edition under the title “Killing Stew”