A savannah in East Africa: gazelles traverse the dry landscape in search of water; the sun burns relentlessly. The animals' path is blocked. Here, in the no man's land between Kenya and Somalia, stands one of the longest fences in the world. It translates into protection of the border over 700 km across desert, forests, rivers and mountains. Such fences have become an everyday sight in the deserts of Africa and elsewhere in the world.
Until recently, little attention was paid to these fences and their role in terms of ecological balance. Yet the millions of kilometres of barriers around the world have an impact on wildlife. Humans' attempt to cut the world into slices also separates the animal world from parts of it.
A threat with many faces
Fences affect the local fauna in many ways: they make access to water and other resources more difficult, block access to habitats, and promote the spread of diseases by keeping animals closer together. Changes that are scientifically proven.
Current studies based on GPS systems show that 80% of all wild animals in areas along fences display drastic changes in behaviour. Sometimes, this is even after fences have long since ceased to exist – and so-called "ghost fences" have arisen.
To give a couple of examples: gazelles die of thirst because they no longer have access to water, and birds get caught in the fences. And the fences become a threat for humans too: the change in the routes of prey animals influences the hunting behaviour of the predators. They use the fences to encircle their prey and, in the process, also encounter people, who are then also at risk.
Long-term impact on ecosystems
Fences have a long-term impact: they can create an ecological no man's land in which only a limited number of species thrive. As more and more fences are being erected at an ever-faster pace, the collapse of many ecosystems is inevitable.
The savannah, mentioned above, is an example of how two completely different ecosystems can be created along fences. Some species spread freely, while others die out due to a lack of food or habitat. The natural balance is permanently disturbed.
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Cultural and social aspects
The whole matter is not an easy one: fences often have a reason for being there. They serve as boundaries that protect nature reserves from external influences, help people to keep their livestock – often their most valuable asset – together, and keep animals away from crops. The ecology of fences is closely intertwined with social and cultural aspects.
This is also one of the reasons why conservationists have thus far tended to turn a blind eye to this. Added to this is the power of habit: we almost don't see the fences anymore, because we have already become so accustomed to them. The realisation that they are a serious problem for wildlife thus came late.
Long-term minimisation of damage
We have to accept that fences will remain. Massively reducing these boundaries on a global scale is simply unrealistic. Therefore, solutions must be found that work with the fences rather than against them.
Fences have an impact not only on wildlife, but also on ecosystem processes. They also constitute an important interface with people and communities. There is much more to learn about the impact of fences."
Andrew F. Jakes, wildlife biologist at the Smithsonian Institute – "A fence runs through it" 2018.
This much is clear: only a better understanding of the interaction between fences and the ecosystem can lead to solutions that do not compromise the benefits of such barriers.
Sometimes these solutions are quite simple: excess fences can be removed, or their height lowered to make them more 'permeable'. A gap under the fence offers animals the opportunity to slip through. Reflectors that increase visibility, portable fences, better mapping, or aligning fences along natural boundaries such as rivers are also helpful.
There are ways to mitigate the harmful effects of fences on a large scale. However, this requires even more scientific data and a holistic understanding of the problem.
We owe it to the animals of the world.
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