The Lesser mole rat (Spalax leucodon) superspecies in eastern Hungary | Photo by Lajos.rozsa/CC BY-SA 3.0 via Wikimedia Commons Mole rats don’t dig Hungary’s migrant fence Some endangered species risk extinction because of the barrier on the Serbian border.

The razor-wire fence on Hungary's border with Serbia built in 2015 to keep thousands of refugees from crossing into Western Europe is claiming unintended victims — the animals that live and move through the region.

For Vojvodina blind mole rats, classified as critically endangered by the International Union for Conservation of Nature, the border barrier patrolled by soldiers and police has turned into an existential threat.

Nannospalax (leucodon) montanosyrmiensis is geographically isolated, living in three small and widely separated populations. One of those clumps just happens to be right on the border, and the fence runs through part of its territory.

The fence splits the already small population, threatening it with extinction, warned the IUCN Small Mammal Specialist Group. That's because the fence poles for the border barrier are dug 2 meters underground and placed in a concrete foundation, right through the rats' tunneled homes. The rats are very sensitive to habitat disruption — they don't live below regularly plowed fields.

Border fences are also appearing along other EU borders, including between Slovenia and Croatia. That one cuts across a designated environmental corridor stretching from Slovenia to Greece. Migrating wolf packs in the region are under close watch, and Eurasian lynxes — recently reintroduced to the area — could be decimated by inbreeding because their populations will be isolated by the fences, said Aleksandra Majic, a biologist at the University of Ljubljana.

In the Balkans, larger carnivores including brown bears, lynxes and wolves have been most affected by the barriers, said John Linnell, a researcher at the Norwegian Institute for Nature Research and author of a recent paper on the environmental impact of border protections.

“The fences in Europe are built in prime wildlife habitat,” he said. “It’s very problematic because these countries claimed the fences were temporary, but now they’re putting up another one.”

Hungary's border fence was a much-criticized reaction to the influx of refugees from conflict in Syria, Iraq and across the Middle East, as well as thousands of migrants from other countries hoping to get to Germany. The fence stands 3.5 meters tall and stretches for 175 kilometers along the whole length of Hungary's border with Serbia.

Now Hungary is planning a second, permanent, border barrier at a cost of €120 million this spring.

Under EU law, construction of that type would typically face an impact assessment to determine its environmental effect. There is a loophole if a country claims the project is crucial to national security, something Hungarian law allows.

NGOs are pushing to have the Hungarian fences removed, but the Ministry of Agriculture refused their request, said Benedek Jávor, a Hungarian MEP from the European Free Alliance. The only remaining option would be to take the issue to national courts, he said.

The Hungarian government insisted the fence isn't causing a problem.

"Every related question was answered at the construction of the first fence and we have dispelled every concern that was raised," the prime minister's office said.

Researchers worry that if fences continue to carve up the Balkan landscape, the Vojvodina blind mole rats could soon be extinct.

"It seems that not a single flightless animal will be able to cross the fence or pass under it," said Attila Nemeth, secretary of the Mammal Protection Group of MME-BirdLife Hungary, an NGO. "For the vulnerable population of Vojvodina blind mole rat this construction is definitely a threat to survival."