The Ecologist


The explorers saw carcass after carcass - animals that had died crossing land that has been home to their species for thousands of years.

More articles about
Related Articles

Fencing plan in South America threatens wildlife

April 16th, 2013

by Katharine and David Lowrie

British Adventure Ecologists Katharine and David Lowrie ask whether there is an alternative to this silent massacre......



For us the fences are merely a hindrance; on which we hitch our clothes and bags upon as we duck under them to make a camp by the roadside. But for wildlife and the wild lands through which they transect, the story is very different.

On one icy stretch of road, nearing El Calafate, southern Argentina, we counted 152 guanaco carcasses in a 10-mile stretch, strung up and mangled in the roadside fence. Guanacos are a ‘humpless’ relative of the camel which inhabit the arid and semi-arid lands of the Andes’ mountainous spine, stretching from southern Chile to southern Peru. Their population, reduced by nearly 95 per cent from the original number believed as much as 50 million, (the World Conservation Society) is now predominantly based in Patagonia, where we counted the carcasses.

The fences create barriers to the herds’ movements, with individuals often becoming entangled as they attempt to leap over them. We watched a family of four each clear a fence, but when it came to the turn of the chulengo (young), it proved impossible; the youngster repeatedly dashing itself against the fence. Heartbroken, we watched the herd move on, leaving the chulengo behind to a probable death without its protection.

After weeks of observation and discussion with farmers, it appeared the fences are not only preventing dispersal and the long-distance migration of herds witnessed by early explorers, but also producing a barricade into which landowners can pursue and shoot the guanacos. One Patagonian Ovejero (sheep-farmer) recounted, “One guanaco drinks the equivalent [water] of 10 sheep and eats the little grass we have”. What he forgets to mention is that guanacos have grazed and browsed the Patagonian steppe for millennia in harmony with the landscape. It wasn’t until the arrival of millions of grazing sheep and cattle, that the entire vegetative structure changed, causing devastating soil erosion.

But it’s not just guanacos who are suffering, we also witnessed a Darwin’s rhea, a huge flightless bird and relative of Australia’s rhea and southern Africa’s ostrich, pounding for miles along a fence desperately trying to find a gap in which it could flea from us.

The impacts of fences upon wildlife and the integrity of wild places are not of course restricted to South America. In the UK, the western capercaillie or “turkey of the woods”, a spectacular bird of old Caledonian pine forests, is on the Red List of Conservation Concern, with studies implicating deer fencing as the cause of mortality for 50 per cent of first year birds. While the famous British symbol of whiskey, the black grouse, is also declining, with 30 per cent of mortalities cited as a result of collisions.

Across the Atlantic in western USA, the near-threatened greater sage-grouse is suffering a similar grizzly death. And on the Mexican-US border, it is not only people who are branded as illegal migrants but black bears, with a study by Atwood et. al (2011) suggesting that the border fences are preventing dispersal and gene flow among the species and threatening populations.

But it is to Australia that one of  the most well known agricultural fence survives; the 1,139 mile state barrier fence or “No. 1 rabbit-proof fence”, crossing north-west through western Australia. The fence constructed as a pest control measure between 1901-07 to restrict movements of introduced rabbits has also proved efficient at impaling and restricting the movement of native species such as: kangaroos, dingoes, echidnas, black-gloved wallabies and spectacled flying fox bats. Two other state fences have also been built and a further 400 mile fence is currently being mooted by the government.

So what can be done to reduce fence mortality rates for wildlife populations to allow essential movement and migration patterns to continue? One solution is to remove them completely. Back in Patagonia, Conservacion Patagonica, a Chilean and Argentinian nature conservation charity, is removing over 400 miles of fencing from a former over-grazed and desertified estancia, Valle Chacabuco, to allow the endangered huemul deer, guanacos, Darwin’s rhea and other species to freely move through the steppe and regain a functioning ecosystem.

One can also look back in time to find solutions to current problems, with husbandry practices proving useful for reducing the need for fencing. For example, for centuries sheep have been “hefted” in the UK, whereby each flock grazes and lives within a specific area, with each knew lamb becoming familiar with the flock’s foraging range. This ancient practice allows different farmers to graze their sheep on the common land and moors of the UK, without the need for fences. And of course the faithful hedgerow; creating a dense line of well-laid native shrubs and trees, that not only prevents livestock straying, but provides habitat for wildlife, with countless wild species in Europe using these green corridors to move through; for forage and shelter.

But when fencing is deemed necessary, it can be constructed with wildlife in mind. In Australia, a “wildlife friendly fencing” project has been created to advise land-mangers on how to reduce wildlife mortality rates, with the first step being to remove barbed wire, which it  believes the greatest fence-related threat to wildlife in Australia, with 75 species recorded ensnared upon it.

In the UK, mammal-gates allow species such as badgers to pass through fences, while bundles of heather or reflective marker plates attached to fences prevent grouse and capercaillies causalities. A study by Stevens et al. (2012) in Idaho, USA, reported an 83 per cent decrease in greater sage-grouse deaths when fences were marked. Understanding animal behaviour, migration routes and patterns can also significantly reduce mortality rates; ensuring fences are sited appropriately; away from foraging habitat, flight paths and key terrestrial pathways.

Fences are not of course always the enemy; properly constructed and sited fences can provide useful tools to prevent mammals, such as deer, from over-grazing wild lands. Rather than enclosing livestock, fences can be used to prevent their ingression into sensitive conservation areas, such as ranched cattle entering the endangered critical ecosystems of Bolivia’s Beni savanna. But although fences provide a  quick construction alternative to their soft vegetative counterparts, they are inferior in quality, lifespan, habitat provision and environmental credentials.

We’re all complicit in this fencing threat to wildlife in our hunt for cheap food, which drives agricultural “efficiency”. So next time you pass by a fence, spare a thought for the wildlife that is impacted and consider that there are strong, time-proven alternatives, as well as modern options that can mitigate this silent massacre. Or as one friend put it, “Try stringing barbed wire across a highway and see how many humans avoid it?!”

Ecologist husband and wife team, Katharine and David Lowrie, are currently 2,500 miles into their world first expedition to run the length of South America, over 5000 miles, in a year, unsupported, for the continent’s wild lands and wildlife.

They pull a trailer they made from recycled materials containing all they need to survive, including: food, water, camping equipment, laptop and binoculars. As well as their daily 20 mile run, they undertake wildlife surveys, present to schools and interest groups and write articles about the environment they’re running through.

Their goal is to connect people from the UK and the world to South America’s remaining wildernesses; showing how our actions impact upon them and how with small steps we can help to conserve them.

To follow Katharine and David’s expedition click and 



Previous Articles...


Using this website means you agree to us using simple cookies.

More information here...