Continental walls of Australia

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

Australia is a vivid example of how a person, thoughtlessly interfering with a natural ecosystem, breaks it down, creating even more problems for himself.

Few people know that at the beginning of the 21st century Australia celebrated its centenary longest structure, created in the entire history of mankind. Oddly enough, this significant event was not accompanied by pompous speeches of politicians and did not receive wide coverage in the international press. The fact is that this structure is just a fence extending from south to north of the Green Continent. Some disparagingly call him Dog wall, but many call The great australian wallproudly announcing that its length is 5323 kilometers, which is almost 600 kilometers longer than the preserved Great Wall of China … The Great Australian Wall looks, of course, incomparably more modest than the Chinese one and is not of particular interest to tourists, as it is made of wire mesh with barbed wire on top.

As a matter of fact, there are three “walls” in Australia now. The first of them was created for fighting rabbits. In 1859, a ship arrived from England to Australia with twenty-four rabbits. Released into the wild (the name of the person who committed this rash act is known is Tom Austin), these seemingly harmless animals are already turned into a real disaster for all farmers in 30 years … The rabbit population grew exponentially, the fight against them turned out to be ineffective, the fields and pastures of the Green Continent were rapidly turning into a desert. To avoid ruin, many kilometers of hedges were erected around the farms, which were originally created from various materials, mainly from various types of wood. Inspection of the condition of the fence at the beginning of the last century was carried out on bicycles, and the position of the chief caretaker was called "inspector of rabbits". On the side of the rabbits, termites unexpectedly appeared, through whose efforts the fences turned out to be very short-lived. Other "allies" of the rabbits were wild camels and local kangaroos. Currently, this hedge divides the continent in half from north to south, its length is 3253 kilometers. This "wall" was built by 400 workers from 1901 to 1907. Despite their best efforts, experts estimate that rabbits currently consume enough grass each year to feed 25 million sheep. Even "biological weapons" turned out to be powerless:the myxomatosis virus, which infected the captured individuals in 1950, and the calcivirus introduced into their population in the 1990s. After the first (and very impressive) successes, individuals resistant to these viruses appeared, as a result, the number of rabbits quickly recovered.

Australian sheep breeders, who found themselves in an even more desperate situation, had to seriously think about the fences around their farms, whose herds were attacked by wild dingo dogs.

Interestingly, dingoes can be seen not only in Australia, but also in Thailand, southeastern China, Laos, the islands of Indonesia, New Guinea and the Philippines. Moreover, the oldest known scientific remains of a dingo dog were found in Vietnam: their age is estimated at about 5, 5 thousand years. But Asian dingos are smaller than their Australian cousins. It is believed that these non-barking, small wolf-sized predators originated from feral dogs brought to the continent from Asia more than three and a half thousand years ago by people who arrived from the islands of Southeast Asia (presumably Sulawesi and Kalimantan). That is, dingoes are secondarily feral animals. The oldest remains of these dogs, found in Australia, are about 3400 years old.

The usual color of these predators is red, or gray-red, but there are groups with a gray or even black color. It is believed that this is due to the mixing of dingoes with the domestic dogs of the settlers. The dingo quickly drove out the few local marsupial predators (their main competitor for a short time was the marsupial wolf) and began to live by hunting kangaroos, birds and reptiles. Later they included rabbits and sheep in their diet, but they can also lift a calf.

Moreover, the easiest and most desirable prey for the dingo was the sheep. … Having attacked the herd, in the hunting excitement, the dogs slaughter many more sheep than they can eat. One dingo family can slaughter a dozen sheep per night. People are not usually attacked by dingoes without provocation, but for Australian farmers, this circumstance was little consolation. The fight against the dingo began in 1788, when the first sheep were brought to the continent. The destruction of dogs was complicated by the dingo's nocturnal lifestyle: during the day they hide in secluded places and go hunting only in the dark. Traps and trapping nets were set on the predators, they were shot and hunted. At the end of the 19th century, in New South Wales alone, farmers annually spent several tons of strychnine to combat wild dogs. For each animal killed, a bonus of 2 shillings was paid. (Payments for a dog killed within a fence can now go up to AU $ 100.) Large shepherd dogs imported from Europe fought successfully with their feral relatives. However, all these measures taken to combat the "red plague of Australia" were not effective enough. In a short time, the dingo population increased a hundred times, while there was a real danger of the destruction of all livestock. In the 1880s. in the state of South Queensland, construction began on a huge mesh fence. Other states followed the example of their neighbors, and by 1901 the entire southwest of Australia was pulled up and down by a wire netting. In the middle of the twentieth century, farmers and local authorities came to the conclusion that in order to more effectively combat predators, the disorderly network of different-sized hedges must be replaced by one fence, which will be supported by deductions from the profits of the ranchers.

As a result, in 1960, three sheep-raising states - Queensland, South Australia and New South Wales - combined their protective hedges into a single wall of wire mesh, dug into the ground to a depth of 30 cm. Currently, the length of this fence is 5 323 km, height - 180 cm. It almost completely crosses the continent, not reaching the western coast of the mainland, only 180 km.

The point, of course, is not the laziness of the Australians and not the lack of funds, but the purely agricultural specialization of unfenced areas: dingoes simply do not go there. Some of its sites are over a hundred years old. Others are newly built and run through their wires a repelling electric current generated by solar panels. In areas where there are many foxes, the fence is cemented to avoid undermining. And in places of mass concentration, kangaroos increase the height of the stakes. Keeping the fence in order is not cheap: the states of Queensland, New South Wales and South Australia spend about A $ 15 million annually. It is necessary to restore the integrity of the mesh quite often - floods and rains undermine the supports, and rust thinns and destroys the mesh. In addition, it is torn by wild camels, kangaroos, emu ostriches, foxes, anteaters and wild boars bury it. Many years of experience have shown that dingoes cannot break through the net, but they do not miss the opportunity to use any gap in order to enter the territory that is forbidden to them. Therefore, special caretakers daily inspect every kilometer of the fence, looking for damage in the net and underground holes made by rabbits or wombats, and destroying dingoes that have penetrated the fence. Previously, they traveled on camels, now they have powerful jeeps at their disposal.

The third Australian wall is not so large-scale, only 44 km long, but quite high - 3 meters. It surrounds the Newhaven National Park and protects its inhabitants from … feral cats.

Australian wild cats

There are about 20 million of them in Australia, and, meanwhile, it is estimated that only 200 cats annually exterminate about 100 thousand rabbits, birds and small animals. It is believed that wild cats kill more than 3 million birds, reptiles and mammals every day - about 2 thousand per minute! Australian authorities are planning to create a predator-free area of about 9,400 hectares.

Now in Australia they are hastily going to build another barrier, this time to protect against reed toads. In Europe, these amphibians themselves are on the verge of destruction, but, inadvertently brought to Australia and having no natural enemies there, they quickly multiplied, "colonized" the state of Queensland and are now moving to the northwest. A real danger threatens the national park on the Coburg Peninsula. Scientists fear that many species of insects and small animals will be destroyed if they fail to block the hordes of toad. The toads must be stopped by a 9-kilometer fence that crosses the isthmus. Reed toads cannot jump, but they dig deep enough holes, and therefore the concrete wall just above half a meter should be almost as deep.