Dingo Fence
The Dingo Fence or Dog Fence is a pest-exclusion fence that was built in Australia during the 1880s and finished in 1885, to keep dingoes out of the relatively fertile south-east part of the continent (where they had largely been exterminated) and protect the sheep flocks of southern Queensland. It is one of the longest structures in the world. It stretches from Jimbour on the Darling Downs near Dalby through thousands of kilometres of arid land ending west of Eyre peninsula on cliffs of the Nullarbor Plain above the Great Australian Bight near Nundroo. It has  been partly successful, though dingoes can still be found in parts of the southern states. Although the fence has helped reduce losses of sheep to predators, this has been countered by holes in fences found in the 1990s through which dingo offspring have passed and by increased pasture competition from rabbits and kangaroos. Geography. The section of the fence in Queensland is also known as the Great Barrier Fence or Wild Dog Barrier Fence 11. It is administered by the Department of Agriculture and Fisheries. The Wild Dog Barrier Fence staff consists of 23 employees, including two-person teams that  patrol a section of the fence once every week. There are depots at Quilpie and Roma. The Queensland Border Fence stretches for westwards along the border with New South Wales, into the Strzelecki Desert. The fence passes the point where the three states of Queensland, New South Wales and South Australia meet (Cameron Corner). At this point, it connects with the South Australian Border Fence, which runs for southwards along the border with New South Wales, these two sections are managed by the New South Wales Wild Dog Destruction Board. It then joins a section known as the Dog Fence  in South Australia, which is long. Physical design. The fence varies in construction. Mostly it is made of high wire mesh but some sections in South Australia comprise multi-strand electric fence. The fence line on both sides is cleared to a width. Sheep and cattle stations in Australia protected by the fence are astoundingly large. While varying in size, some stations can be larger than small countries. One station alone in South Australia lost over 11,000 sheep in a year due to dingo attacks before the completion of the fence. As recently as 1991, one station lost 3000 sheep  in a year . Sheep farmers fought back by using poisoning, shooting, and eventually constructing the longest fence in the world. Aerial poison bait drops are still used today. Parts of the Dingo Fence are lit at night by cold cathode fluorescent lamps which are alternately red and white. They are powered by long life batteries which are charged by photovoltaic cells during the day. At minor and farm crossings, a series of gates allow vehicles to pass through the fence. Where the fence intersects major roads and highways, cattle grids are used to allow high-speed vehicles through. History. The  earliest pest exclusion fences in Australia were created to protect small plots of cropland from the predation by marsupials. In the 1860s and 1870s, introduced rabbit populations began to spread rapidly across southern Australia. By 1884, a rabbit-proof fence was built. Having been unsuccessful at keeping rabbits out, and more successful at keeping out pigs, kangaroos, emus and brumbies, and as more sheep farms were established, the interest for a dingo-proof barrier increased enough that government funds were being used to heighten and expand the fence. In 1930, an estimated 32,000 km of dog netting in Queensland alone  was being used on top of rabbit fences. Prior to 1948, the idea of a Dingo Barrier Fence Scheme had not come into fruition as a statewide project for which annual maintenance and repair were kept. Since this time, there have been pushes to move away from a method of barrier-exclusion to complete extinction of the dingo and wild-dog cross-breeds. Poisoning the species with compound 1080 (sodium monofluoroacetate) baits has been seen as a much cheaper alternative than fence maintenance. A compromise in the form of the continued use of poison and the shortening of the fence  from its previous length of over 8000 km has been made. In 2009 as part of the Q150 celebrations, the dingo fence was announced as one of the Q150 Icons of Queensland for its role as an iconic "innovation and invention". Environmental impact. It seems that there are fewer kangaroos and emus on the northwestern side of the fence where the dingoes are, suggesting that the dingoes' presence reduces the populations of those animals. It has also been suggested that the larger kangaroo populations inside the fence have been caused by the lack of dingo predation, and competition for food  leads to lower sheep stocking rates than would be possible without the fence. Believed to have been introduced into Australia by Aboriginals between 4,600 and 18,300 years ago, the dingo's status as a native or introduced species in Australia has been a controversy. According to Dr. Mike Letnic, at the Centre for Ecosystem Science, UNSW, the dingo, as Australia's top predator, has an important role in maintaining the balance of nature and that reintroduced or existing dingo populations could increase biodiversity across more than 2 million square kilometres of Australia (Avolia 2009). Where dingoes had been exterminated, Dr.  Letnic found increased abundances of introduced red foxes and herbivores, while small native mammals and grasses were lost. In 2011 the Liberal MP for Stuart, Dan van Holst Pellekaan, called for a $200 bounty on dingoes. Although the fence has helped reduce the loss of sheep to predators, the exclusion of dingoes has allowed for increased pasture competition from rabbits, kangaroos and emus. Sheep are being lost to increasing numbers of feral dogs. Drone and satellite technology have illustrated how removing dingos changes vegetation growth.