More than 200 million animals are killed by cars in our country every year? This is how you can save them!

When it comes to human harm to wildlife, many people may first think of poaching. However, some of our daily lives are also threatening the lives of animals , such as cars.

Animals killed by roadkill | Nanjing University Animal Behavior and Conservation Laboratory

With the rapid expansion of road networks, cars and other means of transportation have brought convenience to our lives, but they have also inadvertently caused the deaths of many animals. This situation is called " roadkill ", and hundreds of millions of animals die every year . Around the world, the number of animals killed by collisions with vehicles has exceeded that of hunting, and roadkill has become one of the main causes of death among terrestrial vertebrates[1]. It is estimated that more than 340 million birds are killed on American roads every year[2], which is equivalent to an animal being involved in a car accident every 12 seconds. In some European countries, more than 1/10 drivers admit that they have hit an animal in the past five years.

China also faces a serious roadkill problem. Taking Changbai Mountain National Nature Reserve as an example, 3,475 vertebrate roadkill incidents were recorded in four years, with an average of 61.6 animals killed per 100 kilometers . However, research on roadkill in China has just started, and past research has mostly focused on specific areas such as nature reserves. Will roadkill be more serious in cities with denser road networks ?

A deer killed on a US highway | jjron / Wikimedia Commons

Nanjing: There is a victim every 20 kilometers

Not long ago, Li Zhongqiu’s research team from the Animal Behavior and Conservation Laboratory of Nanjing University conducted a study on the roadkill of vertebrates in the high-density road network of the large city of Nanjing , filling a gap in the research on urban roadkill in China[3].

In 234 surveys over a year, researchers recorded 293 road-killed animals on 224 km of roads, an average of one victim every 20 km . These animals included 21 species, of which domestic cats, dogs, blackbirds and sparrows were the four most commonly killed animals on the road.

Researchers found that road kill peaks in spring and summer, which is also the breeding season, when animals may need to cross roads more frequently in search of mates, and the birth of newborns makes them more likely to be killed by the road.

The study covered national highways, provincial highways and county roads with decreasing traffic volume. Although these roads have different traffic volumes, they have all become places for road kill. The study also found that the locations of animal road kills are not randomly distributed, but concentrated in certain sections of the road , which may be hot spots for animals to pass through the road.

Distribution of animal roadkill roads in Nanjing. Yellow, green and blue are county roads, provincial roads and national roads respectively. Red triangles are where roadkill was found. | Animal Behavior and Conservation Laboratory, Nanjing University

Based on field investigations and combined with Nanjing's nearly 10,000 kilometers of road traffic routes, the researchers constructed a model and found that the number of birds and mammals killed by roads in Nanjing is 470,000 to 610,000 each year. According to the latest "Statistical Bulletin on the Development of the Transportation Industry" released by the Ministry of Transport, the mileage of national highways, provincial highways, and county and township roads in China is 375,400 kilometers, 387,500 kilometers, and 1,902,500 kilometers respectively; therefore, if the situation in Nanjing is extended to the whole country , more than 200 million birds and mammals may die from road kills each year - and this does not include China's huge railway system .

More serious than the data

However, these figures are just the tip of the iceberg.

Although the number of large animals killed on the road is already astronomical, the number of insects that die on the road is more easily overlooked and even greater. Professor Arnold van Vliet of Wageningen University in the Netherlands and his team estimated that every year, a staggering 228 trillion insects die on the world's 36 million kilometers of roads[4].

A British survey asked drivers to stick a postcard-sized piece of PVC film on their windshields. The results showed that an insect would hit the film every 8 kilometers the car traveled.｜H Dragon / Flickr

Roadkill is more than just a statistic; it threatens wildlife populations and affects the ecological balance.

Behind the roadkill problem is the contradiction between human transportation needs and ecological protection. For the ecosystem, the road itself is an invisible obstacle. In addition to direct roadkill, the continuous expansion of road traffic has also caused the fragmentation of the ecosystem - the habitat of wild animals is cut into pieces by roads, making it difficult for wild animals to migrate across roads and find food and mates. This reduces the interaction between different populations, weakens the resilience of the ecosystem, and increases the risk of species extinction.

On the other hand, the roadkill data we investigated only refers to animals that died from roadkill, not the number of times animals collided with vehicles . Sometimes, animals hit by vehicles do not die immediately. They will run away with their injured bodies without being discovered by researchers, but they may suffer pain and disability for the rest of their lives.

A squirrel run over by a car｜Pixabay

What we can do

Can we do anything about road kill? The simplest and crudest solution may be to stop building roads, but this is obviously unrealistic. A relatively feasible way is to avoid hot spots where animals pass through roads when building roads . This requires the formulation and regulation of policies, and policies need more, more comprehensive, and higher-quality data as support. Therefore, we urgently need to collect more data on road kill incidents and animal mortality rates to determine which places are hot spots for animals to pass through roads.

Since data monitoring of animal road kills requires huge time, money and effort, citizen science projects may be a more feasible approach - anyone can become a volunteer for these projects, recording and reporting animal road kills they find, thereby providing a large amount of data for research projects.

For example, the Taiwan Animal Roadkill Observation Network in Taiwan, China, is a roadkill database based on citizen science. This database is open to all citizens. Anyone who encounters an animal killed by the road in the wild can take a photo and upload the photo, date, longitude and latitude and other information to the database in the APP; if possible, the animal carcass can also be sent to a biological conservation center. This kind of national participation will help us understand and solve the roadkill problem more comprehensively.

You can also check the records of the last 30 days on the Taiwan Roadkill Observation Network (TaiRON)｜roadkill.tw

“Once upon a time, most things were natural, with a road connecting a few towns, and that was the corridor. Now, most things are human, and we need natural corridors to connect fragments of nature and habitat.”

—Mitch Friedman, Conservation Northwest

In order to reduce the harm of roads to wildlife, more and more regions have adopted innovative ecological engineering measures. Perhaps the best way is to build " corridors " for animals to pass through.

For example, Canada's Banff National Park built 24 dedicated animal crossings and underpasses to help animals cross roads safely. These corridors are designed to simulate wildlife's natural habitats, attracting animals to cross. The results are very effective: these corridors have eliminated 80% of road kills in the park .

Banff National Park builds a pedestrian bridge for animals｜Ross MacDonald/Banff National Park

Raising public awareness of roadkill is also crucial. In Canada, a non-profit organization called Wildsight organizes wildlife education events and produces information materials to help the public understand how to avoid roadkill when driving in the wild. This kind of education helps change people's behavior and reduce harm to wildlife.

Technology has also provided new tools to reduce roadkill. The Netherlands has not only built ecological corridors on the basis of roads, which allow wildlife to cross safely on the one hand, but also provide opportunities for humans to observe and study on the other hand; infrared cameras and sensor technology are also used in other areas of the road to monitor the activities of animals on the road in real time . Once an animal is detected, the system will automatically trigger a warning sign to remind the driver to slow down. This intelligent technology is expected to become an effective means to reduce roadkill in the future.

Wild animal crossing warning sign on Tibet highway | Nanjing University Animal Behavior and Conservation Laboratory

These examples show how innovation and collaboration are working to reduce road damage to wildlife around the world. Through ecological engineering, ecological corridors, speed limits, public education and technological innovation, we can improve the relationship between roads and wildlife and ensure that wildlife can cross the road safely and freely. This will not only help protect wildlife, but also help maintain ecological balance and harmonious coexistence between humans and nature.

References

[1] Forman, RT and LE Alexander, Roads and their major ecological effects Annual Review of Ecology and Systematics, 1998. 29(1): p. 207-231.

[2] Loss, SR, T. Will, and PP Marra, Estimation of bird-vehicle collision mortality on US roads. The Journal of Wildlife Management, 2014. 78(5): p. 763-771.

[3] Wu, Q., et al., Temporal and spatial patterns of small vertebrate roadkill in a supercity of eastern China. PeerJ, 2023. 11: p. e16251.

[4] Jensen, D., L. Keith, and M. Wilbert, Bright green lies: How the environmental movement lost its way and what we can do about it. 2021: Monkfish Book Publishing.

[5] Wu Qiong, 2023. A preliminary study on roadkill of wild animals in Nanjing. Master’s thesis, Nanjing University.

Author: Yu Cong, Li Zhongqiu

Editor: Mai Mai

Title image source: jjron / Wikimedia Commons

This article comes from GuokrNature (ID: GuokrNature)

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