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Messing with Mother Nature: The Macquarie Island Ecosystem

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The story of the Macquarie Island ecosystem may remind you of the song about the woman who swallowed a fly. The island was exploited mercilessly, but various plans to repair the damage had their own unintended consequences. Introducing a non-native species to control another invasive species can backfire and escalate the situation to ridiculous and tragic levels.

Macquarie Island, part of the Australian state of Tasmania, is a UNESCO World Heritage Site. The island lies in a spot where tectonic plates meet, about halfway between New Zealand and Antarctica, and has unique geological significance. Macquarie is a breeding ground for aquatic life, particularly elephant seals and royal penguins. It is also home to other seals and penguins, several species of albatross and other sea birds, plus a few dozen wildlife scientists and park rangers who work there on a temporary basis. The seals and penguins had no natural enemies on the island until Europeans arrived in 1810. Since then, humans have hatched schemes to either exploit or repair the Macquarie Island ecosystem. Most of these schemes caused further problems.

Polynesians may have inhabited the island in the distant past, but there were no people there when it was discovered by Captain Frederick Hasselborough of the ship Perseverance in 1810. He was looking for seals, and Macquarie Island proved to be a bounty. Fur seals and then elephant seals were hunted almost to extinction on the island. When the seal supply ebbed, penguins were hunted for their oil. Photograph by Wikipedia user Hullwarren.

Meanwhile, any place on earth that was visited by exploring ships ran the risk of introducing rats to the ecosystem. Macquarie Island had no rodents before the seal hunting began, but mice and rats began to flourish soon afterward. Photograph by Wikipedia user Kilessan.

Seafarers knew how to control rats. Most ships had a cat or two just for this purpose. Within ten years of the commencement of sealing, there were feral cats on the island. While rats are omnivores, they only become predators when the easier food is in short supply. Some species of fur seals eat penguins, but the cats were the first land-based true predators on the island. In addition to rodents, the cats ate seabirds.

William Elder of the Otago Whaling Company brought rabbits to the island as a food source in 1870. They, of course, bred like rabbits. Despite being eaten by both cats and people, the wild rabbit population soared to 130,000 on the tiny island within 100 years. Rabbits ate the grass, which allowed erosion to damage the island, and subsequent storms and tremors destroyed erosion-damaged penguin breeding grounds.

look out for dangers

Stoats, a species of weasel, were brought in to control the rabbits on Macquarie Island and in New Zealand soon after the feral population of rabbits became established. Soon the stoat population was helping itself to seabirds and their eggs. Photograph by Flickr user Markus Hoppe.

Possums

As possums were introduced to New Zealand to raise for fur, they made their way to Macquarie Island as well. The cats weren't all that interested in possums, so they bred to the point of becoming pests along with the other introduced species. Photograph by Flickr user Peter Firminger.

As the populations of non-native species grew on Macquarie Island, a time bomb was ticking. When the balance of predators and food supplies reaches a certain point, predators will turn to different species to eat. The Macquarie parakeet flourished on the island until around 1880, when the rabbit supply allowed the number of feral cats to explode, and the cats branched out to eat parakeets. The last Macquarie parakeet was sighted in 1891, and the species became extinct. Of course, the feral cats, while still eating rabbits, went after other native birds. Shown is the red-crowned parakeet of New Zealand, which is similar in appearance to the Macquarie parakeet. Photograph by Thomas Mattern.

Skeleton of sea-elephant & Harold Hamilton

When Macquarie Island began to be used as a science station in the 20th century, seal hunting met its end. Antarctic explorer Douglas Mawson spearheaded the drive to declare the island a nature reserve, and it was his efforts that forced the end of sealing. The last load of oil was taken off the island in 1919. In 1933, Macquarie Island became an official wildlife preserve.

Sea elephants and royal penguins, Macquarie Island, c. 1950s

Meanwhile, as the seal and penguin population slowly began to recover, the island was still overrun with rabbits. Australian scientists hatched a plan to control rabbits (which were out of control in all of Australia) by introducing the virus Myxoma which causes Myxomatosis, a disease fatal to rabbits. First, rabbit fleas were brought to the island in 1968 (yet another invasive species) as a future carrier of the virus. The environment being what it was, the establishment of fleas wasn't as successful as had been hoped. The virus itself was introduced on the island in 1978. The rabbit population plunged from 130,000 to around 10,000, which is the good news. The bad news is that the remaining rabbits were the ones that were immune to the disease.

With most of the rabbits gone, the estimated 500 feral cats on Macquarie Island knew what to do. They ate the native seabirds -up to 60,000 of them every year. The government of Australia decided the only thing to do at that point was to eliminate the feral cats. Cat hunting was encouraged beginning in 1985. The Tasmanian government intensified the program in 1997, using traps and dogs to catch the cats. The last feral cat was caught in 2000. No more cats on Macquarie Island.

Problem solved? Oh no! With the cats gone, those 10,000 rabbits who were immune to the Myxoma virus began to multiply again. The Tasmanian government came to the conclusion that all non-native species had to be eradicated at the same time. That would be the only way to restore the nature preserve to its intended use for the original sea animals. The current eradication program began in 2010. But even that has its problems. The poison bait used to eliminate invasive mammals is working its way through the ecosystem. Just last year, we learned of the death of thousands of seabirds that ate the carcasses of the poisoned mammals. Albatross photograph by Wikipedia user Hullwarren.

Will Macquarie Island ever return to its 18th-century ecological state? Let's hope. Photograph by Wikipedia user Hullwarren.

See also: Messing with Mother Nature: 5 Cautionary Tales

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London's Sewer-Blocking 'Fatbergs' Are Going to Be Turned Into Biodiesel
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UK officials can't exactly transform the Whitechapel fatberg—a 143-ton trash mass lurking in London's sewer system—into treasure, but they can turn it into fuel. As The Guardian reports, Scottish biodiesel producer Argent Energy plans to convert parts of the noxious blockage into an environmentally friendly energy source.

For the uninitiated, fatbergs (which get their names from a portmanteau of "fat" and "icebergs") are giant, solid blobs of congealed fat, oil, grease, wet wipes, and sanitary products. They form in sewers when people dump cooking byproducts down drains, or in oceans when ships release waste products like palm oil. These sticky substances combine with floating litter to form what could be described as garbage heaps on steroids.

Fatbergs wash up on beaches, muck up city infrastructures, and are sometimes even removed with cranes from sewer pipes as a last resort. Few—if any—fatbergs, however, appear to be as potentially lethal as the one workers recently discovered under London's Whitechapel neighborhood. In a news release, private utility company Thames Water described the toxic mass as "one of the largest ever found, with the extreme rock-solid mass of wet wipes, nappies, fat and oil weighing the same as 11 double-decker buses."

Ick factor aside, the Whitechapel fatberg currently blocks a stretch of Victorian sewer more than twice the length of two fields from London's Wembley Stadium. Engineers with jet hoses are working seven days a week to break up the fatberg before sucking it out with tankers. But even with high-pressure streams, the job is still akin to "trying to break up concrete," says Matt Rimmer, Thames Water's head of waste networks.

The project is slated to end in October. But instead of simply disposing of the Whitechapel fatberg, officials want to make use of it. Argent Energy—which has in the past relied on sources like rancid mayonnaise and old soup stock—plans to process fatberg sludge into more than 2600 gallons of biodiesel, creating "enough environmentally friendly energy to power 350 double-decker Routemaster buses for a day," according to Thames Water.

"Even though they are our worst enemy, and we want them dead completely, bringing fatbergs back to life when we do find them in the form of biodiesel is a far better solution for everyone," said company official Alex Saunders.

In addition to powering buses, the Whitechapel fatberg may also become an unlikely cultural touchstone: The Museum of London is working with Thames Water to acquire a chunk of the fatberg, according to BBC News. The waste exhibit will represent just one of the many challenges facing cities, and remind visitors that they are ultimately responsible for the fatberg phenomenon.

"When it comes to preventing fatbergs, everyone has a role to play," Rimmer says. "Yes, a lot of the fat comes from food outlets, but the wipes and sanitary items are far more likely to be from domestic properties. The sewers are not an abyss for household rubbish."

[h/t The Guardian]

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Great Britain's Last Snow Patch Is About to Disappear Completely for the First Time in a Decade

Until recently, it was easy to find snow in Great Britain at any time of the year—you just had to know where to look. In previous Septembers, the island has been home to as many as 678 snow patches, residual pockets of snow and ice whose climates and topographies keep them frozen through the summer. This year, though, only two of Britain's snow patches have survived the summer. And the island is now on track to be completely snowless by the end of the season, Atlas Obscura reports.

Snow patches vary in size and durability, with some melting completely by late summer and others remaining a permanent fixture of the landscape. Garbh Choire Mor—a steep glacial depression on top of Scotland's third-highest mountain, Braeriach—contains two of the oldest snow patches in Britain, known as the Pinnacles and the Sphinx. The Pinnacles snow patch dissolved into a puddle earlier this month, and the Sphinx snow patch, the last surviving snow patch in Great Britain, is expected to do the same in the next few days.

Scotland experienced uncharacteristically hot weather this summer, with temperatures creeping into the low 90s as early as May. But more significant than the sweltering summer was the dry winter that preceded it. Below-average snowfall last year meant this year's snow patches were already smaller than usual when temperatures started heating up. If the Sphinx snow patch does vanish before winter arrives, it will mark the first time in over a decade and just the sixth time in the last 300 years that England, Scotland, and Wales are without a single patch of snow.

The Sphinx snow patch, though currently a measly version of its previous self, is still visible for now. But Iain Cameron, a veteran "snow patcher" who writes an annual report on snow for the UK's Royal Meteorological Society, says it could be gone as soon as Wednesday, September 20.

He's currently camped out on Garbh Choire Mor, waiting to document the patch's final moments. You can follow his updates on Twitter.

[h/t Atlas Obscura]

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