China is building a $1 trillion network of roads, railways, and sea routes that spans four continents.

A new study claims that the project could accelerate the spread of invasive species, including hundreds of birds, reptiles, amphibians, and mammals.

This could have severe financial and environmental consequences.

Few infrastructure projects are grander or more ambitious than China's Belt and Road initiative, which involves building a complex web of roads, railways, and sea routes across four continents and more than 70 different countries.

With a price tag of around $1 trillion, the project is more than an infrastructure investment. It's a global play to integrate the economies of Asia, Europe, and Africa, with China at the helm. Once finished, it could alter the landscape of international trade, forming stronger alliances outside powerhouses like the US.

Read more: Inside 'Belt and Road,' China's mega-project that is linking 70 countries across Asia, Europe, and Africa

It could also cause major damage to the environment, including the spread of invasive species of birds, reptiles, amphibians, and mammals.

If that seems far-fetched, consider the results of a recent study published in Current Biology, which found that areas along the Belt and Road initiative are particularly vulnerable to an invasion of non-native animals.

The China-Kazakhstan logistics terminal was built in 2014 to boost the construction of the Belt and Road. VCG/VCG/Getty Images

To arrive at these predictions, the researchers looked at two factors.

First, they considered whether the species could survive under the conditions of a new habitat. For example, would a frog native to China be able to withstand the temperatures and precipitation in Africa, or have access to the same food and water resources?

Next, they examined what they called "introduction risks" — things like trade, air travel, and maritime shipping that can transport an animal from one location to another.

"Ships often take on ballast water, which can transport aquatic organisms across oceans," said Tim Blackburn, an author of the study. "These days, though, most species are deliberately moved around."

Blackburn pointed to raccoons in Europe, which were once popular as pets, but either escaped or were released into new environments. Studies have shown that the transport of animals via infrastructure has been occurring for thousands of years, but has become more acute with the rise of globalization.

After combining these two factors, the researchers determined various "hotspots" that might witness an invasion of animals, while also providing suitable habitats for the non-native species to live. The majority of these hotspots were located along six economic corridors that make up the Belt and Road initiative.

The European starling is among the hundreds of invasive species mentioned in the study. Allan Hack/Flickr

The arrival of hundreds of invasive species is scary for a number of reasons.

In addition to threatening human health, invasive species like the African clawed frog and ship rat can wipe out native animal populations. Other species like the European starling can destroy crops. In 2012, the starling contributed to $189 million worth of damage to blueberries, wine grapes, apples, sweet cherries, and tart cherries in the US.

Each year, the US loses around $40 billion due to the harm posed by invasive species. Around the world, that damage amounts to trillions of dollars.

While the Belt and Road initiative aims to reduce trade costs, many nations have incurred debt trying to finance their portion of the project.

To prevent further economic hardship, the study's authors recommend setting aside funds to hinder animal invasions. Other researchers insist that the only way to halt the spread is to limit human transport and trade.

"It's hard to limit human activity in towns and cities," said Blackburn. "What we actually need to do is to stop species from getting into new areas."