US President Donald Trump approved the construction of a wall on the border with Mexico with the aim of limiting illegal immigration, as he had promised during the electoral campaign. Besides representing another barrier and a way to further complicating relationships between the two countries, the wall will also pose threats to wildlife.

Wildlife will face an unprecedented challenge

The wall promised by Trump will extend for 1,600 kilometres and could represent an insurmountable obstacle for many animal species that have been roaming these areas for ages, including ocelots (Leopardus pardalis), jaguars (Panthera onca), peccaries (Tayassu pecari), pronghorns (Antilocapra americana), and the northern pygmy owls (Glaucidium gnoma).

The importance of wildlife corridors

Some species, mainly predators and large mammals, occupy wide ranges. For this, wildlife corridors are crucial for animals to move and for plant species to exchange genetic information. The survival of numerous species depends on the possibility of moving freely and finding the best places to find food and shelter and to mate and raise offspring. The importance of interconnected ecosystems has become clearer and clearer in the past decades, thanks to scientific developments in understanding wildlife’s movement patterns.

An increasingly fragmented world

Habitat fragmentation mainly due to urbanisation and infrastructures represents one of the main causes of the alarming decline of many species in the United States. Barriers like walls and highways can interfere with animals’ natural habits, such as seasonal migrations or the exploration of new areas. Limiting their movements also inhibits the exchange of genetic information, making population weaker and vulnerable.

Escaping a changing climate

Insurmountable obstacles like the wall between the US and Mexico would also prevent animals from moving towards different latitudes and escape the effects of climate change. Indeed, many species need to move northwards in order to survive rising temperatures.

The impact of the wall

The Fish and Wildlife Service tried to assess the impact the wall would have on wildlife and conclusions are nothing short of appalling. The wall could significantly affect 111 endangered species, from Texas to California. Also, it will have a huge cost, could be useless for controlling illegal immigration and will represent a setback for conservation efforts, putting at risk wildlife in the name of an absurd electoral promise.