Poland plans to build a wall along its border with Belarus, mainly to block migrants fleeing the Middle East and Asia. But the wall would also divide the vast and ancient forest of Białowieża, a UNESCO World Heritage site that is home to more than 12,000 animal species and includes the largest remnants of the primeval forest that once covered most of the lowlands of Europe.
Borders like this are a priority for conservation as they are often home to unique biodiversity and ecosystems, but are increasingly threatened by the fortification of the border. We are forest ecosystem experts and two of us together have over three decades of experience working in Białowieża, at the crossroads of forest, plant and bird ecology. In the review Science, we recently described how the border wall planned by Poland would endanger this cross-border forest.
The heart of Białowieża is characterized by an ancient forest rich in dead and decaying wood on which mosses, lichens, fungi, insects and also many vertebrates depend. Large animals such as the European bison, wild boar, lynx and wolf inhabit the forest on both sides of the border.
A wall would block the movement of these animals, preventing for example brown bears to recolonize the Polish part of the forest where they were recently observed after a long absence. The wall would also risk invading plants, and would cause noise and light pollution that would displace wildlife. The influx of people and vehicles, and the already accumulated garbage (mostly plastics) also pose risks, including disease – we already know that humans can transmit COVID to wildlife, like the deer.
Poland’s wall will be 5.5 meters high, sturdy, with barbed wire at the top, and will replace a temporary 130 km razor wire fence 2.5 m high built during summer to fall 2021. This wall will be high enough to affect low-flying birds, such as the grouse.
Hindering wildlife more than humans
The wall proposed by Poland resembles the barrier built along parts of the US-Mexico border. Research there based on camera traps shows that such walls deter people less than they hamper wildlife. Animals affected by the US-Mexico barrier include jaguars, pygmy owls and a bison herd whose food and water were shared by the border.
Fences across Europe are very varied, and no mitigation standard exists. A razor wire fence, built in 2015 by Slovenia along its border with Croatia, deer and herons killed with a mortality rate of 0.12 ungulates (hoofed mammals) per kilometer of fence. Along the Hungary-Croatia border, mortality during the first 28 months after the construction of a fence was highest, at 0.47 ungulates per kilometer. Large congregations of red deer have also been observed at the edge of the fence, which could spread disease and disrupt predator-prey dynamics by making them easier to catch for wolves.
People can and will use ramps, tunnel, and alternative routes by air and sea, when wildlife often cannot. The walls have a large human cost too much. They can redirect people, and to a lesser extent wildlife, to more dangerous routes, such as river crossings or deserts, which may cut across areas of great natural or cultural value.
Physical barriers such as fences and walls now line 32,000 kilometers of borders around the world, with a significant increase in recent decades. According to a recent study, nearly 700 species of mammals could now have difficulty interbreeding in different countries, counteract their adaptation to climate change. Fragmentation of populations and habitats means reduced gene flow within less resilient species and ecosystems.
Border security versus climate action
According to the Transnational Institute, rich nations are prioritize border security over climate action, which contravenes the commitments made at COP26 such as protect the world’s forests. Some of the 257 World Heritage forests are now releasing more carbon than they absorb, but Białowieża Forest is still a healthy and well-connected landscape. Poland’s border wall would put that at risk.
The construction of such walls also tends to circumvent or contradict environmental laws. They devalue conservation investments and hamper cross-border cooperation. It was already difficult for us to collaborate with scientific colleagues from Belarus – the new wall will make cross-border scientific work even more difficult.
It is possible to mitigate the effects of certain border barriers. But this requires, at the very least, identifying species and habitats at risk, designing fences to minimize ecological damage, and targeting mitigation measures. known wildlife crossing points. It can also mean assisted migration across a barrier for some species. To our knowledge, no formal assessment of social or environmental costs has yet been carried out in the case of the planned wall in Poland.
It is time for conservation biologists to make their voices heard, especially on the issue of border barriers. As climate change threatens to disrupt borders and the migratory patterns of people and wildlife, we will need to reform not only policies and frameworks, but also the way we perceive borders.
It is is already happening without us like “natural borders flood, drift, crumble or dry up”. Walls – as a reagent travel bans – are not in phase with the global solidarity and the coordinated actions which we urgently need to safeguard life on earth.
Katarzyna Nowak, Białowieża Geobotanical Station, Department of Biology, University of Warsaw; Bogdan Jaroszewicz, professor of biology and director of the geobotany station of Białowieża, University of Warsaw, and Michał Żmihorski, head of research in biogeography, Institute for Research on Mammals, Polish Academy of Sciences