Bison and other animals are at risk from sharpening borders like the Polish-Belarusian wall, which cuts through the Białowieża Forest.
There has been a border-building spree across Europe in recent years.
Fencing at the EU’s external and internal borders grew nearly sevenfold between 2014 and 2022, from 315 to 2,048 kilometres, according to the European Parliament.
Aimed at keeping people out, experts warn these steel walls and barbed wire fences are having a significant – yet often overlooked – impact on animals too.
Eugene Simonov, an activist and researcher at the Ukraine War Environmental Consequences Work Group, tells Euronews Green that borders increase the risk of death as large mammals and birds can easily injure themselves or become tangled in sharp or electrified fencing.
On the “especially wicked” Russian-Mongolian or Russian-Chinese borders, he says herds of hoofed animals can die in great numbers in crushes during their migrations if they are pressed up against the barrier.
Still, nature can adapt.
According to Matthew Hayward, Professor of Conservation at the UK’s University of Newcastle, predators are learning to incorporate fences into their hunting strategies, meaning they can kill bigger and better prey.
Though this may benefit those doing the killing, he says it is an “atypical behaviour” within an ecosystem which could create new pressure on prey populations.
Europe’s borders are stopping wildlife from migrating
Man-made borders create impermeable barriers that animals cannot cross.
The accompanying increase in human activity – with guards patrolling the areas – deters them further, Hayward says.
The professor has studied populations of European bison, wolves, deer and lynx in Europe’s last ancient forest on the Polish-Belarusian border, where Poland’s last government built a high fence more than 180km long and 5.5-metreshigh to keep out illegal migrants.
A key issue is that borders limit the ability of these animals to move across large areas in search of food or more favourable conditions, he says.
This, in turn, can push them into behaviours that drive conflict with humans.
European Bison, typically a forest-dependent species, have moved onto farmland in northeastern Poland because fences were blocking their movement, bringing them into competition with livestock.
Meanwhile, large-scale border fences on the continent of Africa have caused mass deaths of herbivores by blocking their access to water sources.
Fencing off animals into ever smaller pockets of land creates a phenomenon called habitat fragmentation. Also caused by numerous other forms of human activity such as farming or roads, this has been shown to dramatically decrease population size and biodiversity, and is a primary cause of species extinction worldwide, along with habitat loss.
Borders make animal populations ‘less resilient’
Separating animals also limits their gene pool which, in turn, can make them weaker and more vulnerable, according to Hayward.
“Populations will become less resilient to any sort of change,” he says. “They won’t be able to cope with new diseases or climate situations that they have to face.
“They’ll genuinely be under the pump.”
All these effects are jeopardising a “great conservation success story”, says Hayward.
He points out that wild European bison went extinct after the First World War, but have since been revived thanks to Polish and international efforts in the Białowieża Forest, which has regained its position as the world’s breeding centre of the species.
Physical borders have long existed throughout Europe.
But following the end of the Cold War in 1991 and the EU’s expansion, many were dismantled or faded away, allowing wildlife to flourish.
Rising nationalism and political tensions have changed this.
After Brussels slapped sanctions on Belarus over its repression of protesters following elections widely seen as fraudulent, neighbouring EU countries accused Minsk of channelling migrants across the border in a form of hybrid war.
Poland quickly built a wall on its border with Belarus in a bid to keep people out, cutting the Białowieża Forest in half.
These political decisions meant normal environmental impact assessments were waived under the slogan of national security, according to Hayward.
It has also become harder for researchers to cooperate across countries and monitor what impact borders are having in the area, as relations between states have soured, adds Simonov.
Can borders be made safer for animals?
The environmental impact of borders can be reduced, however.
Simonov tells Euronews Green they can be made less dangerous by not using razor wire and that openings can be designed to allow animals to pass.
Another solution is for conservationists to move animals across fences to improve the gene pool, though this subjects them to stress and mortality risks.
But Hayward is sceptical about these “forced interventions” and the extent to which borders can be made more animal-friendly.
“If you put a hole in a fence that is big enough for an animal to get through, it’s going to be big enough for people to get through,” he says.
“Once a fence is up it is almost impossible to get rid of it. Politicians love big fences because they are a clear delineation of what happens on one side [from] the other.”
He suggested instead “friendlier” policies towards immigrants and more foreign aid to help alleviate some of the problems that push people to migrate.
“We need a political solution to what is actually a political problem,” Hayward concludes.
